Arctic Sea Ice : Forum

Cryosphere => Antarctica => Topic started by: Lord M Vader on October 11, 2016, 08:20:11 PM

Title: Sea Ice Extent around Antarctica
Post by: Lord M Vader on October 11, 2016, 08:20:11 PM
As the melting season for the antarctic sea ice seems to have started I think we need a thread which is thought to be used anytime at year to discuss the SIE around Antarctica.

It's fitting that the first post wrt Antarctica SIE is that this years maximum SIE was exceptionally early. According to NSIDC the maximum occurred already by August 31 which is the first time it happens since satellites became operational in 1979 for surveillance of the sea ice there.

To find a lower SIE value for the date of October 10 we need to go back to 1986 and 1984 which were the only other years with a lower SIE for the date. October 10 in 1987 were more or less equal with yesterdays value, though slightly higher.

Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on October 15, 2016, 12:08:41 PM
Hi LMV!

I'm expecting quite an active southern Summer Around Antarctica?

I think we are crashing into a 'post ozone hole/IPO positive' future for ice extent seeing a return of the Weddell polynia and lower sea ice extent maximums.

Even though it is a dire thing I will gain some enjoyment in watching the deniers cope with the loss of their 'go to Squirrel'!
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on October 21, 2016, 12:54:33 PM
After the record early maximum at August 31 the SIE dropped in the beginning of September and more or less plateued. Since October 6 the SIE numbers have steadily dropped with about 600K and per October 19 we are now at 2nd lowest for the date, trailing behind 1986.

In 1984, the SIE as of October 19 was slightly higher but it was followed by a stall lasting into the beginning of November.

As Gray-Wolf pointing out, I don't rule out the possibility of lower SIE maximums in the next couple of years.


Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on October 27, 2016, 05:14:35 PM
Just looking at the graph, it looks like a goodly possibility of a new record minimum. I know it's early, but from what I have read there is an increase of warm water flowing into the area via currents.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 07, 2016, 09:43:11 PM
Per NSIDC extent we are down to 16,108 Mn km2 which is lowest on record for the date. 1986 is on second place about 120K behind.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 08, 2016, 07:00:15 PM
The downward trend continues, 2016 is now 220K ahead of the same time as in 1986.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 09, 2016, 05:39:14 AM
A lot of big drops lately according to JAXA. Another 150k+ reduction today for the Antarctic SIE.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 10, 2016, 05:09:00 AM
Another drop of about 179k km2 posted by JAXA.
Seems momentum is building. A lot of large drops over the last week.
Title: Re: Sea Ice Extent around Antarctica
Post by: JimboOmega on November 10, 2016, 08:30:26 PM
Does anyone have graphs like posted above, but that show the previous records too?
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on November 10, 2016, 09:27:07 PM
Does anyone have graphs like posted above, but that show the previous records too?

Do you mean like attached?
Shows range of 1986 15.94 to 2013 17.63

current value 15.44

To get that just use the bottom grey button shown after the antarctic button at
https://ads.nipr.ac.jp/vishop/#/extent
Title: Re: Sea Ice Extent around Antarctica
Post by: Jim Hunt on November 10, 2016, 09:31:22 PM
Alternatively for NSIDC 5 day averaged extent see:

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/)

and click the "Antarctic" tab. Then click "Show all" at bottom right. Here's one I prepared earlier:

http://GreatWhiteCon.info/2016/10/nsidc-and-cryosat-2-agreed-upon-declining-arctic-sea-ice/#comment-216239 (http://GreatWhiteCon.info/2016/10/nsidc-and-cryosat-2-agreed-upon-declining-arctic-sea-ice/#comment-216239)
Title: Re: Sea Ice Extent around Antarctica
Post by: JimboOmega on November 11, 2016, 02:17:53 AM
Alternatively for NSIDC 5 day averaged extent see:

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/)

and click the "Antarctic" tab. Then click "Show all" at bottom right. Here's one I prepared earlier:

http://GreatWhiteCon.info/2016/10/nsidc-and-cryosat-2-agreed-upon-declining-arctic-sea-ice/#comment-216239 (http://GreatWhiteCon.info/2016/10/nsidc-and-cryosat-2-agreed-upon-declining-arctic-sea-ice/#comment-216239)

Perfect, thanks.

It's a little annoying how they only show previous maximum on their graphs, when minimum seems more relevant.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 11, 2016, 05:36:44 AM
190k+ drop posted by JAXA for Nov 10th. Staying below the curve, even widening ever so slightly.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a) currently at  15,249,442 km2


Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on November 11, 2016, 07:52:46 PM
190k+ drop posted by JAXA for Nov 10th. Staying below the curve, even widening ever so slightly.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a) currently at  15,249,442 km2

almost in free fall and even though the gap is widening ever so slightly, at that level that "slightly" is huge when it comes to excess energy (heat) in the system.

as an example i would use two "identical" cars running above 300km/h while one of the two is "slightly faster by a 5km/h margin, those 5km/h need 10-20% more horsepower, fuel = energy.
Title: Re: Sea Ice Extent around Antarctica
Post by: CalamityCountdown on November 12, 2016, 03:41:15 PM
Originally posted to "stupid questions", but am following Orens suggestion that it be posted to this board. And after reading so many posts in the recent past by "deniers" claiming that growth in antarctic sea ice compensated for the loss of arctic sea ice, the lack of attention in the media to the satellite era record lows being set every day this week is astounding. Today's NSIDC SIE of 15.3 million km's is 600,000 km's lower than the Nov 11 SIE 15.9 million km's in 1986.
According to nsidc.org "Ice extent is particularly low on both sides of the Antarctic Peninsula. The rapid early reduction in sea ice cover in this region may create favorable conditions for the break up of the eastern Peninsula ice shelves at the end of austral summer. Similar sea ice trends and weather conditions were present during the spring seasons preceding past ice shelf retreats (e.g., 2001 to 2002)".  Raises the question of what is the worst case scenario for this year's Antarctic melt season?

A very good question. I suggest you post this in the appropriate thread, Sea Ice Extent around Antarctica.


Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 14, 2016, 04:42:47 PM
According to NSIDC, there have been a big drop in the SIE the last few days:

November 10: 15,072 Mn km2
November 11: 14,902 Mn km2 (-170K)
November 12: 14,615 Mn km2 (-287K)
November 13: 14,427 Mn km2 (-188K)

The five-day average is 14,86 Mn km2. We continue to be lowest on record. On second place is 1986 with a whole 15,715 Mn km2 for November 13. It's a staggering -855K lower than 1986 and more than 1,1 Mn km2 lower than a bunch of years at third place.

It's going fast now!!
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 14, 2016, 05:52:52 PM
That is really something else. I usually check every night with JAXA, which has been down, so I had no idea. There have been some really low SIE minimums, so it would have get pretty low to set a record. At this rate though, who knows?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tealight on November 14, 2016, 11:10:12 PM
What I find most interesting is the anomaly map. It shows that ice isn't just lower near the ice edge, but also close the coast (ice shelfs) and in-between. The Ross Sea Polyna is starting to open a few days earlier than usual too.

http://go.nasa.gov/2fSoviQ (http://go.nasa.gov/2fSoviQ)
Title: Re: Sea Ice Extent around Antarctica
Post by: abbottisgone on November 15, 2016, 10:42:57 AM
Antarctic sea ice has gone missing in action ...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.climate4you.com%2Fimages%2FSeaIceBothHemisphereDailyUpdateGRAPH.gif&hash=a6880181a093abe7f185b1243dbe0406)

(https://www.ncdc.noaa.gov/sotc/service/global/sh-seaice/201609.gif)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 15, 2016, 02:33:44 PM
JAXA  is back up. Their SIE for around Antarctica for Nov. 14th is 14,254,593 km2.

JAXA reports 14,097,448 km2 for Nov. 15th         -157,145 km2

That's approaching 2.5 million km2 less than Nov. 1st
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 17, 2016, 05:33:00 AM
For November 16th, JAXA has posted 13,911,676 km2.

Down by 185,772 km2.    No small drops lately.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on November 17, 2016, 11:02:18 AM
It has been falling by more than twice the pace of all other years and has been the entire reason that global sea ice coverage is now 10 sigma below normal.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 17, 2016, 04:58:48 PM
For the last two days, November 15 and 16, the SIE around Antarctica (NSIDC numbers) has dropped -161K and 173K and the daily value for November 16 was 13,954 Mn km2.

The main question should be how big impact this will have for absorbing the suns energy? Well, one year is no problem but if this is a new trend it will be troublesome. Much of the sea ice will soon experience sun 24/7.

/LMV
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on November 17, 2016, 05:27:03 PM
Hi L.M.V. !

I've spent the " oh look at Antarctica" squirrel years warning the Deniers that the forcings playing a major role ( according to the science?) in the 2% per decade increases would reverse and the ice fall back to the 70's levels...... and then set about the reductions the models predict.

I'm now wondering if this is what we are now starting to see since the IPO flip in 2014 and Ozone hole repairing itself some more?

Obviously there will be swings in extents year to year but the drop back to 70's values would , I imagine, be pretty quick?
Title: Re: Sea Ice Extent around Antarctica
Post by: Ajpope85 on November 17, 2016, 08:25:45 PM
(https://www.ncdc.noaa.gov/sotc/service/global/sh-seaice/201610.gif)

Here's October's anomaly.
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on November 17, 2016, 09:27:28 PM
Hi L.M.V. !

I've spent the " oh look at Antarctica" squirrel years warning the Deniers that the forcings playing a major role ( according to the science?) in the 2% per decade increases would reverse and the ice fall back to the 70's levels...... and then set about the reductions the models predict.

I'm now wondering if this is what we are now starting to see since the IPO flip in 2014 and Ozone hole repairing itself some more?

Obviously there will be swings in extents year to year but the drop back to 70's values would , I imagine, be pretty quick?

As far as my limited understanding goes, Hansen's SLR paper predicted an increase in Antarctic sea ice because of strong freshwater discharge from melting Antarctic glaciers. If that is the case, you should not expect a trend of dropping sea ice extent in the SH.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 17, 2016, 09:40:59 PM
From what I have read about how rough the oceans are right now around Antarctica, I don't think fresh water would stay puddled long. There is a lot of upwelling from the depths. For years this water was cold, but it gradually became warmer and now does more harm than good to both sea ice and ice shelves and some of the glaciers that have a retro-grade from the grounding line inland.

 I think Hansen believed the fresh melt water would have the effect of cooling the surface of the ocean waters. I don't know if he underestimated the amount of warm water upwelling or what, but it's not working out that way. Will have to stay tuned to learn more.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 17, 2016, 09:51:19 PM
Hi guys!

A scientific article published online in Nature by Independence Day 2016 discuss the role of IPO on the SIE change in Antarctica during 2000-2014 when IPO mostly was in its negative phase. Since early 2014 the PDO has been positive and it remains to see whether this a sustained change or a temporary flip.

http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo2751.html (http://www.nature.com/ngeo/journal/vaop/ncurrent/abs/ngeo2751.html)

The article is behind a paywall but some insight can be retrieved from:

https://www2.ucar.edu/atmosnews/news/121622/expanding-antarctic-sea-ice-linked-natural-variability (https://www2.ucar.edu/atmosnews/news/121622/expanding-antarctic-sea-ice-linked-natural-variability)

Washingto Post had an extensive covering about the Nature article: https://www.washingtonpost.com/news/energy-environment/wp/2016/07/05/this-new-antarctica-study-is-bad-news-for-climate-change-doubters/?utm_term=.fd3eadeb5ec0 (https://www.washingtonpost.com/news/energy-environment/wp/2016/07/05/this-new-antarctica-study-is-bad-news-for-climate-change-doubters/?utm_term=.fd3eadeb5ec0)

Another interesting article from Nature is discussing for how much longer Antarctica's ocean can resist global warming:

http://www.nature.com/news/how-much-longer-can-antarctica-s-hostile-ocean-delay-global-warming-1.20978 (http://www.nature.com/news/how-much-longer-can-antarctica-s-hostile-ocean-delay-global-warming-1.20978)
Title: Re: Sea Ice Extent around Antarctica
Post by: JimboOmega on November 18, 2016, 12:29:33 AM
So what exactly is going on this year? Is it just the weather? Is it it something that's preventing glaciers from dumping as much freshwater as usual?

Is this early and strong enough to incur the wrath of positive feedback and warmer than usual waters which will gum up next year's freezing season... or does the presence of glaciers mean that there will be a nice layer of cold, fresh, meltwater atop the southern ocean regardless?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 18, 2016, 05:24:33 AM
Nov. 17th JAXA posted 13,728,295 km2 for Antarctic SIE.

Down 183,381 km2.

If you ever took any of those college courses that had a separate lab class, you probably remember: what you worked out on paper in the class room was not always exactly what happened in the lab. That was the point of taking the lab, to show how much the real world throws you curves.

I don't know about 2014 and prior, but just comparing this year with 2015, I can see why SIE is dropping fast, and with a lot of time left for melting. The ice is literally shredded.
Note: I kept the same amount of zoom and same location and position for each set of comparisons.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 18, 2016, 07:09:52 AM
And yes I did.I looked all around.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 18, 2016, 07:11:56 AM
And around, for good measure and to avoid any bias.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 18, 2016, 07:30:27 AM
The shape this ice is in with three months to go, and the waters are more open than the Arctic and the seas are rough, can we really not expect the melt rate to increase. How strong is the sun in this area, in regard to insolation? So much open water, already. I assume NSIDC and JAXA use the 15% concentration rule for SIE around Antarctica, no?

Sorry, did not mean to hog the thread. I am just awed by what I see happening. I'll tag up now, and let somebody else post.
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on November 18, 2016, 07:32:46 AM
So what exactly is going on this year? Is it just the weather? Is it it something that's preventing glaciers from dumping as much freshwater as usual?

Is this early and strong enough to incur the wrath of positive feedback and warmer than usual waters which will gum up next year's freezing season... or does the presence of glaciers mean that there will be a nice layer of cold, fresh, meltwater atop the southern ocean regardless?
I remember ASLR posting about a tele-connection from the Pacific to the Southern ocean that brings warm water during El-Nino. I don't have any more info on this.

TigerTown, awesome stuff.
Title: Re: Sea Ice Extent around Antarctica
Post by: budmantis on November 18, 2016, 08:12:21 AM

TigerTown, awesome stuff.

Absolutely. TT, do you have any more of those tinfoil hats?
Title: Re: Sea Ice Extent around Antarctica
Post by: LRC1962 on November 18, 2016, 11:17:04 AM
An interesting article of a different type of melting.
http://news.nationalgeographic.com/2016/11/foehn-winds-melt-ice-shelves-antarctic-peninsula-larsen-c/ (http://news.nationalgeographic.com/2016/11/foehn-winds-melt-ice-shelves-antarctic-peninsula-larsen-c/)
A thought that crosses my mind that is not talked about is, if you get a flash thaw of 2-3 days that is enough to work water into cracks, but then you go back into deep freeze, would not that open those cracks even farther as the water expands do to water freezing? Then when in the summer as the air warms would not that be weak points for farther melting?
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on November 18, 2016, 12:54:51 PM
That is exactly the freeze/thaw action that split apart Larsen B into long rafts of ice when it collapsed.

When the ice travels over geographic features it tears apart into crevasses which then heal beyond the obstruction but remain as a weak point. The weak points are then exploited by melt water and are reactivated ( as we saw on Larson B) as the snout reaches the warmer conditions at the coast as it pushed out to form the shelf.

Should the bottom be attacked, and the shelf end up floating, I imagine more pressures are brought to bear on those weak point via wind/wave/tidal forcings?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 19, 2016, 05:09:21 PM
JAXA shows a drop of 109,953 km2 .for the 18th of Nov.

The temperature anomaly over Antarctica seems to be waning, for what it's worth. May only be that it's getting further in the season and not necessarily cooling, but the temps. are no longer that higher than what's expected.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on November 19, 2016, 05:33:30 PM
If you put warm water into one corner of a large swimming pool....eventually it's going to make to ALL PARTS of the swimming pool.  And that is what is happening to the Antarctic.

I think the problem with detailed scientific models.....is that they have been TRYING to predict something that has an UNPREDICTABLE TIME SCALE.  All the serious scientists know what is happening and what the root cause is.....but trying to "time it" seems impossible.

It's not surprising to me that the Antarctic sea ice is now decreasing in size to record lows.  IT HAD TO EVENTUALLY.  All parts "of the pool" are now being noticeably affected.  The EXTENT of what is coming may be a surprise (I certainly didn't think that up to 9 feet by 2050 - 2060 was coming)....BUT....the basic physics told me that "some increasingly crappy things" are going to be happening to (1) the ice (2) the level of ocean rise and (3) atmospheric temps.

And I also think that the issue in the publics mind has been "overcomplicated".....and thus dismissed by many of them. 



 
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 20, 2016, 05:02:43 AM
For Nov. 19th JAXA  reports Antarctic SIE to be at 13,443,895 km2.

That is down 174,447 km2 from the 18th.
Title: Re: Sea Ice Extent around Antarctica
Post by: AbruptSLR on November 20, 2016, 06:52:33 PM
I originally post the following in the Arctic folder, but it belongs here as much as there:

While I have no proof of any correlation between the two polar sea ice deviations from their respective norms; nevertheless, I cannot help but to suspect that the recent large El Nino is contributing to the Antarctic low sea ice extent, while the associate weak La Nina is contributing the Arctic low sea ice extent (& and both deviations could be strengthened by positive cloud feedbacks).  Paleo-data and model forecasts provide weight to such a possible chaotic strange (Lorenz) attractor type of behavior.


Edit 1: See the linked article entitled: "Lorenz attractors, fluids, chaos and climate".

https://moyhu.blogspot.com/2016/11/lorenz-attractors-fluids-chaos-and.html (https://moyhu.blogspot.com/2016/11/lorenz-attractors-fluids-chaos-and.html)

Edit 2: The following four linked references all indicate that consideration of chaos theory's strange attractors in paleo-eras demonstrate that climate sensitivity is higher than traditional (AR5) climate modeling projections have assumed.

1) Jones, R. N. and Ricketts, J. H.: Reconciling the signal and noise of atmospheric warming on decadal timescales, Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-35, in review, 2016.

http://www.earth-syst-dynam-discuss.net/esd-2016-35/ (http://www.earth-syst-dynam-discuss.net/esd-2016-35/)
&
http://www.earth-syst-dynam-discuss.net/esd-2016-35/esd-2016-35.pdf (http://www.earth-syst-dynam-discuss.net/esd-2016-35/esd-2016-35.pdf)

2) Roger Neville Jones & James Henry Ricketts (2016), "Atmospheric warming 1997–2014: hiatus, pause or regime?"

https://www.researchgate.net/publication/305989994_Atmospheric_warming_1997-2014_hiatus_pause_or_regime (https://www.researchgate.net/publication/305989994_Atmospheric_warming_1997-2014_hiatus_pause_or_regime)

3) Ragone, F., Lucarini, V. & Lunkeit, F. (2016), "A new framework for climate sensitivity and prediction: a modelling perspective", Clim Dyn, 46: 1459. doi:10.1007/s00382-015-2657-3

http://link.springer.com/article/10.1007/s00382-015-2657-3 (http://link.springer.com/article/10.1007/s00382-015-2657-3)

4) Anna S. von der Heydt, Peter Ashwin (Submitted on 12 Apr 2016), "State-dependence of climate sensitivity: attractor constraints and palaeoclimate regimes",  arXiv:1604.03311


http://arxiv.org/abs/1604.03311 (http://arxiv.org/abs/1604.03311)
&
http://arxiv.org/pdf/1604.03311v1.pdf (http://arxiv.org/pdf/1604.03311v1.pdf)

Edit 3: The last linked reference cite model findings indicating that changes in extratropical clouds associated with a reduction in high latitude albedo can impact poleward atmospheric heat transport via changes in the Hadley cell:

Nicole Feldl, Simona Bordoni & Timothy M. Merlis (September 28 2016), "Coupled high-latitude climate feedbacks and their impact on atmospheric heat transport", Journal of Climate, DOI:http://dx.doi.org/10.1175/JCLI-D-16-0324.1


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0324.1 (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0324.1)

Abstract: "The response of atmospheric heat transport to anthropogenic warming is determined by the anomalous meridional energy gradient. Feedback analysis offers a characterization of that gradient and hence reveals how uncertainty in physical processes may translate into uncertainty in the circulation response. However, individual feedbacks do not act in isolation. Anomalies associated with one feedback may be compensated by another, as is the case for the positive water vapor and negative lapse rate feedbacks in the tropics. Here we perform a set of idealized experiments in an aquaplanet model to evaluate the coupling between the surface albedo feedback and other feedbacks, including the impact on atmospheric heat transport. In the tropics, the dynamical response manifests as changes in the intensity and structure of the overturning Hadley circulation. Only half of the range of Hadley cell weakening exhibited in these experiments is found to be attributable to imposed, systematic variations in the surface albedo feedback. Changes in extratropical clouds that accompany the albedo changes explain the remaining spread. The feedback-driven circulation changes are compensated by eddy energy flux changes, which reduce the overall spread among experiments. These findings have implications for the efficiency with which the climate system, including tropical circulation and the hydrological cycle, adjusts to high latitude feedbacks, over climate states that range from perennial or seasonal ice to ice-free conditions in the Arctic."
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 21, 2016, 04:54:07 AM
From Sept. 1st to Nov. 19th, every fifth day
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 21, 2016, 05:04:38 AM
JAXA reports 13,239,201 km2 SIE  around Antarctica for Nov. 20th.

Down 204,694 km2

Sept. 1st compared to Nov. 20th
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on November 21, 2016, 06:09:25 AM
Tigertown, I really appreciate your efforts in documenting the ongoing rapid decline in the Antarctic sea ice! I'm interested in it almost as much as I am the Arctic sea ice, especially now since it seems to be showing new behavior.
Title: Re: Sea Ice Extent around Antarctica
Post by: budmantis on November 21, 2016, 08:11:30 AM
I'll second that, nice graphic!
Title: Re: Sea Ice Extent around Antarctica
Post by: Archimid on November 21, 2016, 03:11:06 PM
It looks like a potential poof.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 21, 2016, 04:55:45 PM
For November 20, the Antarctica SIE saw a double century break. In exact numbers, the drop was -225K. We are now down at 13,258 Mn km2 according to NSIDC values.

//LMV
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on November 21, 2016, 05:02:12 PM
From Sept. 1st to Nov. 19th, every fifth day

Nice...  And Archimid is spot on....poof is right.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 22, 2016, 05:13:49 AM
For Nov. 21st JAXA reports 13,083,541 km2 SIE for the Antarctica area.

That's a drop of 155,660 km2.

The graph shows this rate that is averaging out of late to be about the normal rate of melt for Antarctic sea ice over the past years. However, the bigger drops and the mixed in double century plus drops this year have the melt about two weeks or so ahead of schedule and that could easily be enough to wrap up in mid-Feb. under 1M km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on November 22, 2016, 02:24:51 PM
I am looking for....but cannot find (I've looked on the JAXA site and NSIDC...but maybe I am blind)...the data that sits behind all the graphs they produce.  Specifically:

1)  Antarctic sea ice extent MAXIMUM by year
2)  Antarctic sea ice extent MINIMUM by year
3)  Antarctic sea ice VOLUME MAX by year
4)  Antarctic sea ice VOLUME MIN by year

If I can get the data TABLES then obviously I can cull through and pick out the max and min's myself.  But I can't find access to the tables.  I want to make a couple of bar charts...and need that data to do so.

Anyone have any links that might help me would be greatly appreciated.... :)

Title: Re: Sea Ice Extent around Antarctica
Post by: Jim Hunt on November 22, 2016, 05:32:14 PM
Anyone have any links that might help me would be greatly appreciated.... :)

Volume is tricky, but NSIDC daily extent is here:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/south/daily/data/

and for JAXA see:

https://ads.nipr.ac.jp/vishop.ver1/data/graph/plot_extent_s_v2.csv

Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on November 22, 2016, 07:10:32 PM
Thanks for the links Jim.... :)
Title: Re: Sea Ice Extent around Antarctica
Post by: Neven on November 22, 2016, 10:30:25 PM
Buddy, remember, there are a lot of links to a lot of things at the top of the ASIG front page (https://sites.google.com/site/arcticseaicegraphs/).
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 22, 2016, 10:42:22 PM
What to expect for sea ice around Antarctica?
First frame from Nov. 21(most recent image available)
Second frame is forecast ice for Jan. 1st
Third frame is forecast ice for Jan. 31st
Forecast taken from Climate Reanalyzer
Click to animate please.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 23, 2016, 06:08:19 AM
JAXA reports SIE around Antarctica at 12,998,302 km2 for Nov. 22nd

Down 85,239 km2
Title: Re: Sea Ice Extent around Antarctica
Post by: JimboOmega on November 23, 2016, 11:50:22 PM
What to expect for sea ice around Antarctica?
First frame from Nov. 21(most recent image available)
Second frame is forecast ice for Jan. 1st
Third frame is forecast ice for Jan. 31st
Forecast taken from Climate Reanalyzer
Click to animate please.

It looks like the Ross ice shelf totally melts out.  It even looks like polynya are starting to form there  right now.  Is either of those things normal?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 23, 2016, 11:57:43 PM


It looks like the Ross ice shelf totally melts out.  It even looks like polynya are starting to form there  right now.  Is either of those things normal?

I think all the ice shelves in these images are shadowed in with the land mass, as these are not considered to be the same as sea ice and thus not counted with sea ice extent.
See image below.
Title: Re: Sea Ice Extent around Antarctica
Post by: uniquorn on November 24, 2016, 12:35:07 AM

Second frame is forecast ice for Jan. 1st
Third frame is forecast ice for Jan. 31st

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
interesting forecast, but the images are dated 2016. typo?
Title: Re: Sea Ice Extent around Antarctica
Post by: JimboOmega on November 24, 2016, 01:48:12 AM


It looks like the Ross ice shelf totally melts out.  It even looks like polynya are starting to form there  right now.  Is either of those things normal?

I think all the ice shelves in these images are shadowed in with the land mass, as these are not considered to be the same as sea ice and thus not counted with sea ice extent.
See image below.

That makes a lot of sense. I was wondering why the sheets didn't cleanly line up.

I guess given its vastly different properties - being so much thicker - it's not so meaningful (or unusual) for the front between sea and ice to be there.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 24, 2016, 03:06:02 AM

That makes a lot of sense. I was wondering why the sheets didn't cleanly line up.

I guess given its vastly different properties - being so much thicker - it's not so meaningful (or unusual) for the front between sea and ice to be there.
One of the ice shelves, Larson C, has a long crack and is in danger of breaking off soon, making a giant iceberg. There is a thread about it, if you haven't  seen it.

http://forum.arctic-sea-ice.net/index.php/topic,1175.0.html
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 24, 2016, 04:39:33 AM
For Nov. 23rd JAXA has posted SIE around Antarctica to be  12,896,355 km2.

Down 101,947 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: SteveMDFP on November 24, 2016, 08:33:51 PM
Wipneus' global sea ice area chart continues grabbing eyeballs.  Prominently featured now in the Boston Globe, in an editorial by Bill McKibben:
https://www.bostonglobe.com/opinion/columns/2016/11/22/one-chart-captures-alarming-decline-sea-ice/ndn2lcr80WxKfetCfbzDsI/story.html (https://www.bostonglobe.com/opinion/columns/2016/11/22/one-chart-captures-alarming-decline-sea-ice/ndn2lcr80WxKfetCfbzDsI/story.html)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 25, 2016, 04:25:08 AM
For Nov. 23rd JAXA has posted SIE around Antarctica to be 12,736,966 km2.

Down 159,389 km2.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 25, 2016, 04:53:49 AM
One of the last large intact areas of sea ice is about to break up. This is about 850 km from Ross Ice Shelf. This area was several hundred thousand km2, and will only break up more now.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 26, 2016, 04:35:23 AM
JAXA has posted 12,616,192 km2 for SIE around Antarctica for Nov. 25th...

Down 120,774 km2 from the 24th...
Title: Re: Sea Ice Extent around Antarctica
Post by: Feeltheburn on November 26, 2016, 06:43:41 AM
So what about the article being circulated by WUWT that according to explorer log books from 100 years ago the Antarctic ice is unchanged? I'm sure the log books were unbiased and relatively accurate. What about the interpretation?
Title: Re: Sea Ice Extent around Antarctica
Post by: Feeltheburn on November 26, 2016, 06:59:39 AM
I read that some say that collapse of Ross shelf would dramatically raise seal level. So what is the volume of the shelf above water? I read that about 90% of the ice is below seal level. In addition, when ice melts its density increases from about 0.9167 g/cm3 to about 1 g/cm3. That means the total volume of the ice, if melted, would not be much more than the volume of ice already under water. So if the unthinkable happened and the Ross ice shelf completely melted, how much would it raise sea levels? It doesn't appear to me that melting would have much affect at all since the volume of ice, when melted, would be reduced to about the volume of ice already underwater, which already displaced an equal volume of water throughout the world's oceans.

Or would it be a bell weather of other catastrophic events that will raise the sea level, like the melting of the ice pack on Antarctica? Just curious why scientists predict massive sea level rise without considering the net effect of melting on density and volume. If they mean it will be a bell weather of other bad things it would be more accurate to say so. Otherwise, it is easy to criticize their alarmism if their predictions don't hold water, so to speak.
Title: Re: Sea Ice Extent around Antarctica
Post by: SteveMDFP on November 26, 2016, 07:10:24 AM
I read that some say that collapse of Ross shelf would dramatically raise seal level. So what is the volume of the shelf above water? I read that about 90% of the ice is below seal level. In addition, when ice melts its density increases from about 0.9167 g/cm3 to about 1 g/cm3. That means the total volume of the ice, if melted, would not be much more than the volume of ice already under water. So if the unthinkable happened and the Ross ice shelf completely melted, how much would it raise sea levels? It doesn't appear to me that melting would have much affect at all since the volume of ice, when melted, would be reduced to about the volume of ice already underwater, which already displaced an equal volume of water throughout the world's oceans.

Or would it be a bell weather of other catastrophic events that will raise the sea level, like the melting of the ice pack on Antarctica? Just curious why scientists predict massive sea level rise without considering the net effect of melting on density and volume. If they mean it will be a bell weather of other bad things it would be more accurate to say so. Otherwise, it is easy to criticize their alarmism if their predictions don't hold water, so to speak.

No, Feeltheburn, you haven't caught scientists in a massive blunder.  We all know that the melting of floating sea ice does not directly raise sea levels.  The problem with ice shelf destruction is that these shelves buttress glaciers that flow toward the sea.  Eliminate the buttressing, and glaciers speed up dramatically.

Massive sea level rise from Antarctica does not require one square km of the surface to ever be above freezing. 
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on November 26, 2016, 09:34:53 AM
I read that some say that collapse of Ross shelf would dramatically raise seal level. So what is the volume of the shelf above water? I read that about 90% of the ice is below seal level.
FTB again it seems you are reading too many denier sources and get confused in the process.
Ice shelves and ice tongues by their very definition are floating. Floating ice when it melts doesn't change sea level except for some salinity-related negligible stuff. So does it mean all is well and we are saved? No, unfortunately.
Antarctica is raising sea levels by its glaciers flowing towards the sea more quickly (in terms of water mass) than the snow that gets deposited on the continent. When glaciers are accelerating and their calving fronts retreat, sea level rises more quickly. When ice shelves collapse, glaciers are significantly accelerated.
Note that you should worry more about Pine Island Glacier and Thwaites Glacier in West Antarctica instead of the Ross ice shelf, in terms of earlier risk of SLR.
Finally, I recommend that you pick one thread per week in the Antarctica sub-forum (or actually anywhere on the Cryosphere sub-forum) and read it from its beginning 2-3 years ago. You will gain a lot of knowledge and be less confused by deniers sowing misinformation and disinformation.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 26, 2016, 01:46:11 PM
NSIDC has a drop of -144K for today.
Title: Re: Sea Ice Extent around Antarctica
Post by: wili on November 26, 2016, 02:25:37 PM
ftb, please stop reading WUWT unless you want to be continually misinformed. And if you must insist on reading there, please stop bringing their tripe over here. And if you insist on bringing it here, ask about it in the proper forum...stupid questions. Thanks.

Here's Leland Palmers comment on your question about the thin and ancient data:

Suppose I was to apply this method today, with much better global positioning data, and much more uniform recording methodology. Suppose I was to gather data from 14 voyages over 20 years, and compare that to computer models (I get to pick which models, of course) and claim that from that limited amount of data I could calculate the boundaries of the Antarctic sea ice in limited areas throughout the year.

I think that scientists would question any conclusions I came to from this very limited amount of data. The yearly variation in sea ice extent alone is pretty large, not to mention variations in collection methodology, observer bias, and so on.

https://robertscribbler.com/2016/11/23/climate-change-has-left-bolivia-crippled-by-drought/
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 26, 2016, 02:33:47 PM
We have gone over it a couple times in this thread. When ice shelves melt or fall off, they raise sea level. Glaciers do as well. Neither are the same as sea ice. Many ice shelves rise tall above sea level and are not floating, though a portion of these sit below the water.
Title: Re: Sea Ice Extent around Antarctica
Post by: be cause on November 26, 2016, 02:51:31 PM
some folk's goal here is to dilute threads thus reducing their value . I'm beginning to think there may be good money in doing so .. causing distraction and repetition is more subtle than just playing stupid ..
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on November 26, 2016, 02:57:37 PM
We have gone over it a couple times in this thread. When ice shelves melt or fall off, they raise sea level. Glaciers do as well. Neither are the same as sea ice. Many ice shelves rise tall above sea level and are not floating, though a portion of these sit below the water.
Thanks. I stand corrected. Even feeding trolls can be instructive.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 26, 2016, 03:15:13 PM
We have gone over it a couple times in this thread. When ice shelves melt or fall off, they raise sea level. Glaciers do as well. Neither are the same as sea ice. Many ice shelves rise tall above sea level and are not floating, though a portion of these sit below the water.
Thanks. I stand corrected. Even feeding trolls can be instructive.
I can't say too much, as I am guilty myself of not reading a whole thread every time.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on November 26, 2016, 04:50:41 PM
FTB again it seems you are reading too many denier sources and get confused in the process. <snip>.

i'm not that sure whether it's confusion, the quota of such posts a quite a bit high, like inspector columbo would say " i don't believe in coincidences " LOL
Title: Re: Sea Ice Extent around Antarctica
Post by: S.Pansa on November 26, 2016, 06:03:48 PM
We have gone over it a couple times in this thread. When ice shelves melt or fall off, they raise sea level. Glaciers do as well. Neither are the same as sea ice.

Are you sure about that? Would be great if some of the experts on the forum could clarify that. I was sure it is like Oren has said above:

Many ice shelves rise tall above sea level and are not floating, though a portion of these sit below the water.

This seems definitely wrong to me. An ice shelf  (https://en.wikipedia.org/wiki/Ice_shelf) is by definition floating ice, as fare as I know. From the linked Wiki article:

An ice shelf is a thick floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface.

See also the figure below from here (http://www.antarcticglaciers.org/antarctica/west-antarctic-ice-sheet/), especially the grounding line.

My understanding thus fare was: Only when the land ice has crossed the grounding line (the line that seperates the ice sheet from the ice shelf) it contributes to sea level rise - but on the long run only, if the ice mass loss through the ice outflow is greater as the mass gain ( through precipitation for instance). Is that wrong?   

PS. I just read in the linked Wiki article above, that the melting of ice shelfs does indeed rise sea level, but only marginally. The ice from the WAIS alone would rise sea levels by +3 meters.

Although it is believed that the melting of floating ice shelves will not raise sea levels, technically, there is a small effect because sea water is ~2.6% more dense than fresh water combined with the fact that ice shelves are overwhelmingly "fresh" (having virtually no salinity); this causes the volume of the sea water needed to displace a floating ice shelf to be slightly less than the volume of the fresh water contained in the floating ice. Therefore, when a mass of floating ice melts, sea levels will increase; however, this effect is small enough that if all extant sea ice and floating ice shelves were to melt, the corresponding sea level rise is estimated to be ~4 cm.[10][11][12]

However, if and when these ice shelves melt sufficiently, they no longer impede glacier flow off the continent, so that glacier flow would accelerate. This new source of ice volume would flow down from above sea level, thus resulting in its total mass contributing to sea rise.
Title: Re: Sea Ice Extent around Antarctica
Post by: AbruptSLR on November 26, 2016, 06:16:41 PM
Are you sure about that? Would be great if some of the experts on the forum could clarify that.

In general terms I concur with S.Pansa's points; however, I note that ice shelves also serve to buttress marine glaciers so as the ice shelves degrade their buttressing action also degrades.  This results in an acceleration of the ice flow velocity of the marine glaciers; which typically resulting in a faster rate of sea level rise.
Title: Re: Sea Ice Extent around Antarctica
Post by: S.Pansa on November 26, 2016, 06:22:41 PM
That was fast :)
Thanks AbruptSLR for the clarification & the additional info about the buttressing effect!
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 26, 2016, 06:47:22 PM
The amount that sea ice or ice shelves raise sea level is estimated to be about 2.6% of its volume. We usually don't even worry about this with sea ice because it is usually small amounts, and while it is thawing at one pole it is freezing at the other and will return in each one respective season anyway. That's in a normal world of course. As less freezes back each year, it will have some impact.

The difference with ice shelves, especially in this thread because its Antarctica we are talking about, is simply that these are extremely huge and towering compared to sea ice and thus the 2.6% is no longer negligible.

P.S.I apologize for an earlier comment that an ice shelf raises sea level instantly upon calving. That much was wrong. It has to melt first.
And I should not have equated ice shelves with glacier ice, which goes entirely toward sea level rise.
Title: Re: Sea Ice Extent around Antarctica
Post by: AbruptSLR on November 26, 2016, 08:07:07 PM
I apologize for an earlier comment that an ice shelf raises sea level instantly upon calving. That much was wrong. It has to melt first.
And I should not have equated ice shelves with glacier ice, which goes entirely toward sea level rise.

Just to be clear, ice shelves consist of glacial ice and it can take decades (depending largely on size) for them to melt, even after calving.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 26, 2016, 09:19:31 PM
I am sorry if I caused confusion in the way I worded that. I only meant to differentiate  ice shelves and glaciers in the sense of a scenario in which a glacier (that is in a position to do so) calves off directly into the ocean and the effect on sea level, whether it melts sooner or later. It would all go to raising sea level, whereas the ice shelf is glacial ice that's no longer grounded but floating has a marginal effect. I wasn't trying to say it was a different kind of ice.

My guess would be that in the good old days it didn't matter as much. As glaciers pushed out past the grounding line and made shelves, and some broke free and floated off, the glaciers were rebuilt at a similar rate from snowfall and so forth. Only as the cycle starts to fail, does it matter. No?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 27, 2016, 04:36:47 AM
For Nov. 26th JAXA has posted 12,460,979 km2 for SIE around Antarctica.

Down by 155,213 km2 from the 25th.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 27, 2016, 05:16:05 AM
Ok, fine gentlemen involved in earlier discussion about ice shelves. A little belated addition to the discussion. I dug around trying to remember where my reasoning came from. The 2.6% of total volume of the ice shelf added to sea level may be low in most cases.Why? Simply because buoyancy only partially supports the ice shelf. The rest of the support comes from the fact that the shelf is in cantilever situation over the grounding line.

I think that I may have been under the impression that the cantilever was a larger portion than it actually is of the two. After further review, I see that the buoyancy is. Of course as the glacier pushes the shelf outward, the downward pressure becomes too great for the available buoyancy and a shear occurs. Then the cycle repeats until getting out of balance again.

I thank you all for pushing me to learn more.
Title: Re: Sea Ice Extent around Antarctica
Post by: Steven on November 27, 2016, 12:45:19 PM
'Remarkable year': What's behind the record low sea ice in Antarctica (http://www.smh.com.au/environment/climate-change/remarkable-year-whats-behind-the-record-low-sea-ice-in-antarctica-20161125-gsxo4p.html)


The Weddell polynya indicates there were unusually warm waters beneath, but researchers won't know for sure until they can retrieve and analyse data from floats, Dr Reid said.

Some extreme weather, which also brought in warmer air from the north, may have helped corral the thinning ice into smaller areas. "That atmospheric pattern exacerbated the regions of lower-than-normal sea ice," he said.

...

A gauge of the relative strength of the westerly winds that circumnavigate Antarctic – known as the Southern Annular Mode (SAM) – had also turned negative in November.

That means higher-than-usual pressure over the continent and lower pressure at mid-latitudes, a set-up conducive to a hot, dry start to summer, the bureau said this week.

"It's well known that a negative SAM is associated with less sea ice, so it seems likely that this has played a part in the decrease of ice during November," Dr Turner said.

The bureau's Dr Reid said the big El Nino in the Pacific – rated third strongest during the satellite era – was also a factor in making sea ice behaviour down south a more complicated tale than at the North Pole.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.smh.com.au%2Fcqstatic%2Fgsy9rv%2Fweb_icemelt.jpg&hash=aa8fdefc84a949a66262b461f7153bf1)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 28, 2016, 05:13:37 AM
For Nov. 27th JAXA has posted 12,318,519 km2 for SIE around Antarctica.

Down by 142,460 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 28, 2016, 07:40:00 AM
From NSIDC, the drop at Nov 26 was even bigger, -193K. The SIE isnow at 12,485 Mn km2 which is about a million km2 lower than 1986 at the moment.
Title: Re: Sea Ice Extent around Antarctica
Post by: Feeltheburn on November 28, 2016, 08:14:12 AM
I read that some say that collapse of Ross shelf would dramatically raise seal level. So what is the volume of the shelf above water? I read that about 90% of the ice is below seal level.
FTB again it seems you are reading too many denier sources and get confused in the process.
Ice shelves and ice tongues by their very definition are floating. Floating ice when it melts doesn't change sea level except for some salinity-related negligible stuff. So does it mean all is well and we are saved? No, unfortunately.
Antarctica is raising sea levels by its glaciers flowing towards the sea more quickly (in terms of water mass) than the snow that gets deposited on the continent. When glaciers are accelerating and their calving fronts retreat, sea level rises more quickly. When ice shelves collapse, glaciers are significantly accelerated.
Note that you should worry more about Pine Island Glacier and Thwaites Glacier in West Antarctica instead of the Ross ice shelf, in terms of earlier risk of SLR.
Finally, I recommend that you pick one thread per week in the Antarctica sub-forum (or actually anywhere on the Cryosphere sub-forum) and read it from its beginning 2-3 years ago. You will gain a lot of knowledge and be less confused by deniers sowing misinformation and disinformation.

Oren, thanks for the beat down. As a luke-warmer I will continue reviewing all sides, thank you very much. More to the point, if your and other's response to my questions are that (1) I'm too stupid to be asking questions and (2) I should get informed elsewhere before wasting your time here, then what is the purpose of this forum? If you and everyone else only want to hear words that confirm what you already know, is it really a forum or just a testimonial blog? Seems to me that you and others have a golden opportunity to answer those of us who have legitimate questions. Simply slamming me as just another stupid denier is not winning me over, and it won't win anyone else over who isn't already singing in the choir.

On the other hand, you were much harder on me than on the responder who stated, incredibly, that the Ross Ice shelf will in fact cause sea levels to rise because it is sticking far above the sea surface than normal sea ice. I have read no scientific argument that this is the case. Nor could it be unless (1) the Ross Ice shelf is not floating but sitting atop an underwater continental shelf of land, in which case it's not really an "ice shelf" but an ice cap of sorts, (2) it is so strong and rigid that it is fastened to the edge of the continent with enough force so as to be cantilevered, or (3) it is floating in the midst of a previously unknown levitation field. If (1) and (2) are actually true, then the Ross Ice shelf isn't likely to break up anytime soon. If it's (3) then God help us!

My questions may irritate you and others, but at least I don't say things like the ice shelf isn't floating but is suspended in mid-air by unknown forces. Of course, the law of gravity and Archimedes principle tell us that, if the ice shelf is floating on top of the water like any other sea ice, when melted, the resulting volume of melted water will exactly equal the volume of water displaced by the weight of the ice shelf. Hence, no sea level rise.

Of course, if the real situation is that the ice shelf is acting as a dam to stop the flow of glaciers to the sea, then I get that. That is the nuanced argument that needs to be made. Not the manifestly false assertion that the ice shelf itself will raise sea levels. That was my point and it's not misinformation.
Title: Re: Sea Ice Extent around Antarctica
Post by: Feeltheburn on November 28, 2016, 08:21:35 AM
ftb, please stop reading WUWT unless you want to be continually misinformed. And if you must insist on reading there, please stop bringing their tripe over here. And if you insist on bringing it here, ask about it in the proper forum...stupid questions. Thanks.

Here's Leland Palmers comment on your question about the thin and ancient data:

Suppose I was to apply this method today, with much better global positioning data, and much more uniform recording methodology. Suppose I was to gather data from 14 voyages over 20 years, and compare that to computer models (I get to pick which models, of course) and claim that from that limited amount of data I could calculate the boundaries of the Antarctic sea ice in limited areas throughout the year.

I think that scientists would question any conclusions I came to from this very limited amount of data. The yearly variation in sea ice extent alone is pretty large, not to mention variations in collection methodology, observer bias, and so on.

https://robertscribbler.com/2016/11/23/climate-change-has-left-bolivia-crippled-by-drought/

Thanks Willi. You made my day. I always like teachers who tell students they're just plain stupid. You are so smart and I'm so dumb. Thanks for wasting 10 seconds of your day to tell me so.
Title: Re: Sea Ice Extent around Antarctica
Post by: Feeltheburn on November 28, 2016, 08:27:59 AM
We have gone over it a couple times in this thread. When ice shelves melt or fall off, they raise sea level. Glaciers do as well. Neither are the same as sea ice. Many ice shelves rise tall above sea level and are not floating, though a portion of these sit below the water.

Ok TT, I didn't see anywhere where you've gone other this. Can you provide me a source that explains how and why the Ross Ice shelf "rises tall above see level and [is] not floating"? What would be the cause of this gravity defying phenomenon? Is the shelf sitting atop a solid underlying surface? Or is it so strong and tightly fixed to the edge of the continent so as to be cantilevered? Can hundreds of miles of ice be cantilevered at the edge? If you've explained, thanks in advance. However, I must have missed it so please give me a link.
Title: Re: Sea Ice Extent around Antarctica
Post by: Feeltheburn on November 28, 2016, 08:33:51 AM
We have gone over it a couple times in this thread. When ice shelves melt or fall off, they raise sea level. Glaciers do as well. Neither are the same as sea ice. Many ice shelves rise tall above sea level and are not floating, though a portion of these sit below the water.

Tigertown, I got my information regarding ice shelves floating from NISDC, which incidentally, shows the same view of Antarctica's ice shelves but with the statement that:

https://nsidc.org/cryosphere/quickfacts/iceshelves.html

"Because ice shelves already float in the ocean, they do not contribute directly to sea level rise when they break up. However, ice shelf collapse could contribute to sea level rise indirectly. Ice streams and glaciers constantly push on ice shelves, but the shelves eventually come up against coastal features such as islands and peninsulas, building pressure that slows their movement into the ocean. If an ice shelf collapses, the backpressure disappears. The glaciers that fed into the ice shelf speed up, flowing more quickly out to sea. Glaciers and ice sheets rest on land, so once they flow into the ocean, they contribute to sea level rise."

That is the nuanced view that I agree with. I don't agree with your assertion that a melting ice shelf will by itself contribute to sea level rise.
Title: Re: Sea Ice Extent around Antarctica
Post by: Neven on November 28, 2016, 11:02:54 AM
FTB, three requests:

Stop the concern trolling. Final warning.

Read all of the comments before quoting.

Think about the buttressing.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 28, 2016, 04:38:40 PM
FTB. As I pointed out, I myself have had to make some adjustments in my thinking about this matter.
As I pointed out, while there is a cantilever force involved with these,it is not the dominant one. Buoyancy carries most of the load. When the cantilever starts to carry too much, shearing becomes imminent. This would prevent the shelf in and of itself from ever being in a situation to cause sudden, large scale sea level rise. Only that it would no longer be there to protect the glacier, and that would be a concern for sea level.

You have my sincere apologies. You will note that I never called you names or continuously belittled you, even when I thought I was right, as that is not my policy.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 28, 2016, 05:17:18 PM
Big drop today, -223K according to NSIDC. We are somewhat less than 1 Mn km2 lower than 1986 and another 400K lower than third lowest year for the date 11/27..

1982 holds the current record for earliest date to cross the 12Mn-mark. It did so at about December 5. The 5-day average for December 6 in 1982 was 11,805 Mn km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on November 28, 2016, 06:39:26 PM
On a more realistic optimistic note, we are now less than 1 million km² below the old record on IJIS for the date, the first day since November 11.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on November 28, 2016, 07:19:30 PM
@Feeltheburn

it's not the content and/or the questions as a standalone, it's the quota that caused some reaction.

dunno if a "devils advocat" is a valid term in english as well but to be one of those is as well not the purpose of the forum as far as i understood. i think that compared to other of the over 100, mostly tech forums that i'm still active in from the time before retirement this forum is an extremely liberal place and it takes quite some time and an obvious pattern in posting until the dirt starts to hit the fan :-) further this forum, again as compared to many others, is full of well founded know how
and thorough observations and pondering which make this place a good daily read and learning
platform with emphasis on reading :-)

enjoy furhter and sorry if i was one of those who came across a bit rude, all will be fine i think :-)

cheers

Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on November 28, 2016, 10:35:02 PM
As we saw with Larsen B ice shelves can depart their anchorage very swiftly and surveys in the mid noughties linked this behaviour to Ross.

In the early noughties it was found that Ross was becoming warm enough to experience such disruption if that warming continued.

By 2012 the warm waters that had been travelling down from the Peninsula arrived at Ross.

Seeing as we now appear to be seeing both the IPO flip and the last Nino's impacts clobbering Sea ice I have to wonder if we will see an uptick in major calves over the coming Austral summer?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 29, 2016, 04:25:02 AM
For Nov. 28th JAXA has posted 12,116,756 km2 for SIE around Antarctica.

Down by  201,763 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on November 29, 2016, 11:16:55 AM
Good article: http://www.smh.com.au/environment/climate-change/remarkable-year-whats-behind-the-record-low-sea-ice-in-antarctica-20161125-gsxo4p.html (http://www.smh.com.au/environment/climate-change/remarkable-year-whats-behind-the-record-low-sea-ice-in-antarctica-20161125-gsxo4p.html)

Edit: sorry, I didn't notice that Steven had already linked to this above.

-------------------------------------------------------------------------------------------------------------


GIOMAS modelled Antarctic sea ice volume until 2012, as plotted by Wipneus:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F1229%2Fgiomas_cwp7.PNG&hash=1113694e97fbb224dbbdebd562ceaaed)
https://sites.google.com/site/arctischepinguin/home/giomas (https://sites.google.com/site/arctischepinguin/home/giomas)


Some papers about thickness/volume of Antarctic sea ice:

Thickness distribution of Antarctic sea ice: http://onlinelibrary.wiley.com/doi/10.1029/2007JC004284/full (http://onlinelibrary.wiley.com/doi/10.1029/2007JC004284/full)

A model reconstruction of the Antarctic sea ice thickness and volume changes over
1980–2008 using data assimilation
:  http://nora.nerc.ac.uk/501476/1/massonnet_etal_OCMOD13.pdf (http://nora.nerc.ac.uk/501476/1/massonnet_etal_OCMOD13.pdf)

Satellite observations of Antarctic sea ice thickness and volume: http://onlinelibrary.wiley.com/doi/10.1029/2012JC008141/full (http://onlinelibrary.wiley.com/doi/10.1029/2012JC008141/full)

Antarctic sea-ice freeboard retrieval using CryoSat-2: possibilities, limitations, uncertainties: http://epic.awi.de/37542/ (http://epic.awi.de/37542/)

About the consistency between Envisat and CryoSat-2 radar freeboard retrieval over Antarctic sea ice: http://epic.awi.de/41243/ (http://epic.awi.de/41243/)

ICESat measurements of sea ice freeboard and estimates of sea ice thickness in the Weddell Sea: http://onlinelibrary.wiley.com/doi/10.1029/2007JC004284/full (http://onlinelibrary.wiley.com/doi/10.1029/2007JC004284/full)

--------------------------------------------------------------------------------------------


I think it's also worth remembering that ESMR passive microwave satellite data are available for 1972-1976. For instance:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F2927%2Fantarctic_sea_ice_nov_1976_vjp5.PNG&hash=3b9cd1b19f928f3c579cb7781aecef37)

Maps available here: http://ntrs.nasa.gov/search.jsp?R=19840002650 (http://ntrs.nasa.gov/search.jsp?R=19840002650)
ESMR extent data from Cavalieri et al. 2003 available here: ftp://sidads.colorado.edu/pub/DATASETS/nsidc0192_seaice_trends_climo/total-ice-area-extent/esmr-smmr-ssmi-merged/ (http://ftp://sidads.colorado.edu/pub/DATASETS/nsidc0192_seaice_trends_climo/total-ice-area-extent/esmr-smmr-ssmi-merged/) (these data need a small upward adjustment to match NSIDC Sea Ice Index numbers from 1978: ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/ (http://ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/))

For comparison purposes, this is the latest map from Uni Bremen:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F9136%2FAntarctic_AMSR2_nic_nwc5.png&hash=c993331474ec0beafca2c945da4b7864)


1976 is currently the second lowest year, as we can see at the graph below, that shows some of the lowest years of the 1973-2016 time series (2016 updated until November 28th):

(https://diablobanquisa.files.wordpress.com/2016/11/antar7316sel.png)


I have also found an interesting paper by Ackley (1981, http://hydrologie.org/redbooks/a131/iahs_131_0127.pdf (http://hydrologie.org/redbooks/a131/iahs_131_0127.pdf)) who presents data compiled by Kukla et al. (1977). The graph below shows late November Antarctic sea ice extent from 1967 to 1976. I think this graph is very intereresting because, as far as I know, it is the only contemporary attempt to present a "long" time series. It's also remarkable because it is the only time series that covers the 1972-1973 boundary between visible imagery and passive microwave data:

(https://diablobanquisa.files.wordpress.com/2016/10/antar-67-72.png)


I have extracted the data from that graph, and compare them against ESMR Cavalieri numbers for 1972-1976. They match very well with November 25th ESMR numbers, so I have been able to plot the graph below. Late November Antarctic sea ice extent from 1967 to 2016:

(https://diablobanquisa.files.wordpress.com/2016/11/antarseaice6716_nov.png)

The current Antarctic sea ice extent is the lowest for late November from 1967 as well.
There is a small downward trend from 1967 to 2016, although taking into account the larger error margins of the 67-72 numbers and the high interannual variability, maybe we should understand that the trend 1967-2016 is basically flat.


Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on November 29, 2016, 07:20:45 PM
Another big drop today according to NSIDC, -213K. By tomorrow we will most likely cross the mark of 12 Mn km2. December is the month with the biggest losses. A "normal" year, Antarctica sees a SIE drop of about 5Mn km2, or roughly -170K per day.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on November 30, 2016, 01:30:26 AM
(https://diablobanquisa.files.wordpress.com/2016/11/csic_figure4.png)

(https://diablobanquisa.files.wordpress.com/2016/11/csic_figure3.png)

(https://diablobanquisa.files.wordpress.com/2016/11/csic_figure6.png)

https://neptune.gsfc.nasa.gov/csb/index.php?section=234


----------------------------------------------------------------------------------------------------------------------


(https://diablobanquisa.files.wordpress.com/2016/11/antar7316sel.png)
ftp://sidads.colorado.edu/pub/DATASETS/nsidc0192_seaice_trends_climo/total-ice-area-extent/esmr-smmr-ssmi-merged/
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/



Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 30, 2016, 04:23:58 AM
For Nov. 29th JAXA has posted 11,913,271 km2 for SIE around Antarctica.

Down by 203,485 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on November 30, 2016, 02:05:10 PM
1986 was the lowest year for all of Oct and Nov until this year. The 1987 minimum less than 4 months later was above average.

That isn't what we would expect in Arctic where more open water would be expected to have albedo effect trapping more heat that would melt more ice.

Question: Should we expect fast melt out due to low extent or slow Antarctic sea ice decline like 1986/7 over next 4 months?

I don't have any knowledge or much of a clue to offer but wonder: Is low extent at this time of year likely an indicator of low winds failing to push ice away from land. Does this mean the remaining ice spent longer in ice growth latitudes and so is thicker and is therefore harder to melt out?

1986/7 is just one year and could easily be an oddity. Next few lowest years are more mixed but possible still show a small tendency for recovery rather than becoming more extremely low.

Any thoughts anyone?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tealight on November 30, 2016, 03:02:14 PM
1986 was the lowest year for all of Oct and Nov until this year. The 1987 minimum less than 4 months later was above average.

That isn't what we would expect in Arctic where more open water would be expected to have albedo effect trapping more heat that would melt more ice.

Question: Should we expect fast melt out due to low extent or slow Antarctic sea ice decline like 1986/7 over next 4 months?

I don't have any knowledge or much of a clue to offer but wonder: Is low extent at this time of year likely an indicator of low winds failing to push ice away from land. Does this mean the remaining ice spent longer in ice growth latitudes and so is thicker and is therefore harder to melt out?

1986/7 is just one year and could easily be an oddity. Next few lowest years are more mixed but possible still show a small tendency for recovery rather than becoming more extremely low.

Any thoughts anyone?

I'm not an Antarctic expert, but my concentration maps help a lot more than just plain numbers. At the minimum the biggest area of remaining ice is east of the Antarctic Peninsula and somewhat west of the Ross Sea. Everything else is very likely to melt out and would only contribute very little area.

I don't know where 1986 had low sea ice concentrations, but this year looks pretty average in those areas. Maybe its enough for a new record low, but the minimum is already very low and requires almost a complete melt out. 1993 went as low as 1.29 million km2 for sea ice area.

Daily updates are working again
https://sites.google.com/site/cryospherecomputing/daily-data-antarctic

(https://docs.google.com/uc?id=0B5JYfcI0wFH6dGs3YmQ5QVZTcEE&export=download)
(https://docs.google.com/uc?id=0B5JYfcI0wFH6NDVIdlR5aUJ1aTA&export=download)
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on November 30, 2016, 03:30:49 PM
I don't know where 1986 had low sea ice concentrations, but this year looks pretty average in those areas. Maybe its enough for a new record low, but the minimum is already very low and requires almost a complete melt out. 1993 went as low as 1.29 million km2 for sea ice area.

The interesting thing to me....will be the effect on global temperatures and SST's as BOTH polar sea ice areas will be at or near record lows at the SAME TIME.

My "logic cap" tells me that can't be good news for temps of the oceans and the atmosphere.  I might suggest that any hoped for downturn or "plateau" in atmospheric temperatures after such a steep 3 year run in atmospheric temperatures.....may be fleeting and short lived at best.

 

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on November 30, 2016, 03:43:40 PM
Antarctica at mid Feb. from 2003-2016
Not really dealing with a lot of MYI
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on November 30, 2016, 06:48:40 PM
-------------------------------------------------------------------------------------------------------------


GIOMAS modelled Antarctic sea ice volume until 2012, as plotted by Wipneus:

https://sites.google.com/site/arctischepinguin/home/giomas[/url]


I have updated most of the graphs there with the latest GIOMAS data that ends with May 2016. Some of them still to go.

Here is the SH anomaly graph showing a sharp drop in volume anomaly in the first few months of 2016 (indicating a slow growth in the first part of the freezing season). Without recovery that is bound to be a factor causing the current low ice cover.

About GIOMAS:

# Data: GIOMAS http://psc.apl.washington.edu/zhang/Global_seaice/ (http://psc.apl.washington.edu/zhang/Global_seaice/)
# Ref: Zhang, Jinlun and D.A. Rothrock: Modeling global sea ice with a thickness and enthalpy distribution model in generalized curvilinear coordinates (http://psc.apl.washington.edu/zhang/Pubs/POIM.pdf), Mon. Wea. Rev. 131(5), 681-697, 2003

(click for a bigger picture)
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on November 30, 2016, 07:28:03 PM
Thanks for the update, Wipneus!

Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on November 30, 2016, 07:45:30 PM
Lowest years of the 1973-2016 timeseries (updated until November 29th):

(https://diablobanquisa.files.wordpress.com/2016/11/antar7316sel_nov_29.png)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 01, 2016, 04:34:16 AM
For Nov. 30th JAXA has posted 11,697,965 km2 for SIE around Antarctica.

Down by 215,306 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on December 01, 2016, 11:41:53 AM
Dr. Zhang was kind enough to update the GIOMAS data to the latest full month (October) after I contacted him.

So the graphics need another update, here is the anomaly graph showing a persistent low volume compared with recent years (but not compared with those in the 20th century). 
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 01, 2016, 12:53:13 PM
Three and a half months to go to minimum, and the volume anomaly is nearly tied for earlier this year. Ouch!
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 01, 2016, 01:05:13 PM
So the graphics need another update, here is the anomaly graph showing a persistent low volume compared with recent years (but not compared with those in the 20th century). 

That will be interesting to watch over the next couple of years, if it continues to stay persistently low....
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on December 01, 2016, 01:49:19 PM
Three and a half months to go to minimum, and the volume anomaly is nearly tied for earlier this year. Ouch!

Right it is anomaly, the absolute volume numbers show that there is still long way to go (but we are starting off far lower than e.g. last year)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 01, 2016, 02:23:58 PM
Three and a half months to go to minimum, and the volume anomaly is nearly tied for earlier this year. Ouch!

Right it is anomaly, the absolute volume numbers show that there is still long way to go (but we are starting off far lower than e.g. last year)

Gotcha. It's early morning here and I tried to put my brain in gear before the oil warmed up.

In anomalies for dummies terms; it was low earlier this year compared to what it would have normally been at the time, and is low now compared to what it should be now, but to a slightly lesser degree.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 02, 2016, 04:53:36 AM
For Dec. 1st JAXA has posted 11,508,508 km2 for the SIE around Antarctica.

Down by 189,457 km2.

Melt momentum.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 02, 2016, 07:55:49 PM
For the last three days the SIE drops around Antarctica were according to NSIDC:

Nov. 29: -284K
Nov. 30: -151K
Dec. 1:   -180K

We continue to be lowest on record.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 03, 2016, 05:42:29 AM
For Dec. 2nd JAXA has posted 11,318,272 km2 for SIE around Antarctica.

Down by 190,236 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 03, 2016, 08:31:38 PM
NSIDC reports a drop of 156K today.

/LMV
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 04, 2016, 04:28:57 AM
For Dec. 3rd JAXA has posted 10,999,093 km2 for SIE around Antarctica.

That makes for a large drop of  319,179 km2.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on December 04, 2016, 08:52:00 PM
For Dec. 3rd JAXA has posted 10,999,093 km2 for SIE around Antarctica.

That makes for a large drop of  319,179 km2.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)

yeah, certainly there were not that many of those in the past, at least not at this time of the season.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on December 05, 2016, 12:44:47 AM
Lowest years of the 1973-2016 time series (updated until December 3rd) :

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F9742%2Flowest_dic_03_bwn0.PNG&hash=78bf4299d9a7197ac8c9097d19059f64)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 05, 2016, 04:35:07 AM
For Dec. 4th JAXA has posted 10,787,419 km2 for SIE around Antarctica.

Down by 211,674 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 06, 2016, 04:46:58 AM
For Dec. 5th JAXA has posted 10,615,432 km2 for SIE around Antarctica.

This is a drop of 171,987 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Sarat on December 07, 2016, 02:12:53 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fnsidc.org%2Farcticseaicenews%2Ffiles%2F1999%2F12%2Fmonthly_ice_11_SH.png&hash=03a32be47efd6100ad31b11b733c9359)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 07, 2016, 04:33:23 AM
For Dec. 6th JAXA has posted 10,450,939 km2 for SIE around Antarctica.

Down by 164,493 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Andre on December 07, 2016, 02:10:43 PM
@Tigertown: I wanted to thank you for your continued efforts in posting the daily Antarctic SIE. It is much appreciated and a welcome addition to the forum. I hope you will continue posting your daily updates.
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on December 07, 2016, 05:56:05 PM
Though it is quite reasonable to put down this years 'odd' low ice situation to mere 'variability' in the climate.

That said if the 'reasons' given for the slow growth in Antarctic sea ice, since the early 80's, are to be believed then the opposite of that impact would cause a rapid drop off in ice extent around Antarctica back to levels common in the 70's?

We know the Ozone hole is mending and we know the IPO flipped positive in 2014.

Add into that the extra warmth in our world since the 70's we might even be looking for extent to fall below the 70's values?

So keep up the good work Tigertown! we may be watching a very important event unfolding
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 07, 2016, 06:02:56 PM
Thank you all for your kindness , but I do have to say, true credit has to go to LMV, who opened this thread with perfect timing. And it does seem it will be an exceptional year for Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on December 07, 2016, 11:00:22 PM
I can't shake the feeling that the sharp drop in Antarctic sea ice is related to the El-Nino of last year. I wouldn't be surprised to see it bounce back up in a year or two.
Regardless of the cause, a very low extent of sea ice can have a large impact even if it's only for one year. Open water could heat up under insolation and help calve ice shelves, and potentially could help move away some calved icebergs that have been hanging around for ages, thus reducing buttressing on future glacier flow. Just some hunches, nothing scientific here. But this year could cause some major damage.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on December 08, 2016, 03:10:22 AM
I can't shake the feeling that the sharp drop in Antarctic sea ice is related to the El-Nino of last year. I wouldn't be surprised to see it bounce back up in a year or two.
Regardless of the cause, a very low extent of sea ice can have a large impact even if it's only for one year. Open water could heat up under insolation and help calve ice shelves, and potentially could help move away some calved icebergs that have been hanging around for ages, thus reducing buttressing on future glacier flow. Just some hunches, nothing scientific here. But this year could cause some major damage.

relation as you see it is certainly true while it's still lower than before under similar circumstances. GLOBAL warming will more sooner than later lead to lower and lower lows while the up and down from year to year, due to other factors will continue for sure and after the latest el nino and it's aftermath, chance for a rebound is most probably but the trends will be downwards in the long run.

we shold always put into account that we are looking at accelerated processes that in the past took millenia if not longer to take place and the faster changes happen the steeper the up and downs will look on any graph. i hope the basic meaning is understandable of what i want to say while there are certainly many members who can explain this better and in better english.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 08, 2016, 04:24:13 AM
For Dec. 7th JAXA has posted 10,249,836 km2 for SIE around Antarctica.

Down by 201,103 km2.
Dec. 1-7
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on December 08, 2016, 07:01:31 AM
...i hope the basic meaning is understandable of what i want to say while there are certainly many members who can explain this better and in better english.
You are perfectly understandable and your English is just fine.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 08, 2016, 06:52:02 PM
For the last couple of days, the drops are as follows:

December 3: -284K
December 4: -230K
December 5: -211K
December 6: -215K
December 7: -172K

The value for December 7 is 10,166 Mn km2.

If we want to keep the first place when 2017 begins we need to see another drop of about 4,2 Mn km2. The lowest value on record at New Year is 5,967 Mn km2 which was reached by January 1 in 1980. That means that we need to lose about 175K every day. Should be a tough mission to fulfill despite that we are lowest on record today, but certainly not impossible.

For the next two weeks or so, the biggest losses should be east of the West Antarctic peninsula.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 09, 2016, 04:26:58 AM
Whoa!

For Dec. 8th JAXA has posted 9,976,242 km2 for SIE around Antarctica.

Down by 273,594 km2.

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 09, 2016, 04:30:22 AM
...i hope the basic meaning is understandable of what i want to say while there are certainly many members who can explain this better and in better english.
You are perfectly understandable and your English is just fine.
And I can add to that; I always look forward to your input magnamentis.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on December 09, 2016, 06:23:08 AM
Whoa!

For Dec. 8th JAXA has posted 9,976,242 km2 for SIE around Antarctica.

Down by 273,594 km2.
oh my god it seems to be keeping up perfectly with staying around 1 million km² below the old record

We should continue to see huge extent drops over the next few days as the ice on the eastern side of the hook north of the Weddell polynya (not exactly a polynya anymore) as it blinks out of vision of JAXA.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on December 09, 2016, 04:29:29 PM
...i hope the basic meaning is understandable of what i want to say while there are certainly many members who can explain this better and in better english.
You are perfectly understandable and your English is just fine.
And I can add to that; I always look forward to your input magnamentis.

thanks sir, did you ever consider what may happen soon, once the antarcic costs becomes more or less "blue", what will happen once more and significant amounts of rock (land) surface becomes exposed to sunlight and relatively early in the season as that? i suspect that there is a certain possibility to see an acceleration of land-ice melting soon ( similar to greenland) that would contribute significantly to SLR.

not directly releated to extend but less extent that early will have a huge impact on albedo IMO while i lack the necessary education to understand how all that is related, what do you think?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 09, 2016, 05:06:57 PM
For my part, I think the Whole climate is connected and that what happens in one place effects the other. I believe there is a tele-connection between the Arctic and Antarctic. What I have my doubts about is the strength of the sunlight that is to be absorbed in the extreme south compared to the Arctic areas. Still, it should at least contribute to the overall situation.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 09, 2016, 05:35:02 PM
For December 8, NSIDC has a triple century break, down with -316K and is now at 9,850 Mn km2.The 5-day average for December 8 is however 10,334 Mn km2.

Second lowest year on record is now 1982 which for December 8 had a SIE of 11,313 Mn km2. For the last 10 days or so in December, 1979 holds the value for the lowest on record.

December 30 in 1979 had a SIE of 6,376 Mn km2 with can be compared to the average of 7,598 Mn km2 for the same date.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 09, 2016, 05:48:35 PM
For my part, I think the Whole climate is connected and that what happens in one place effects the other. I believe there is a tele-connection between the Arctic and Antarctic. What I have my doubts about is the strength of the sunlight that is to be absorbed in the extreme south compared to the Arctic areas. Still, it should at least contribute to the overall situation.

No different than pouring in hot water in one corner of a pool.  EVENTUALLY....it effects THE WHOLE POOL.

What "concerns" me most right now....is the large deficiency in sea ice.....and the additional amount of heat that the southern oceans are now being FORCED to absorb.  That is going to speed up melting of the shelf ice and the movement of the glaciers towards the ocean.  I think we're heading deeper and deeper into the global warming wilderness.

I thought we might get to a "turning point" this past summer with the Arctic....but that petered out.  We're getting a lot closer now....

Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on December 09, 2016, 07:49:49 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F3575%2Fantarc7316_dec_08_abn0.PNG&hash=530afaf59b38730225be230750e408db)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F8237%2Fantarc7316_dec_08_lowest_2_xty5.PNG&hash=6221f28e138ba44df2507e7705fedb66)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 10, 2016, 04:57:13 AM
For Dec. 9th JAXA has posted 9,720,337 km2 for SIE around Antarctica.

Down by 255,905 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 10, 2016, 10:15:09 PM
If I take a look at the following chart with the COMBINED global sea ice levels that include both the Arctic and Antarctic sea ice levels....with the blue line being the average from 1981 - 2010, and the red line being the 2016 combined sea ice levels.....there are a few "obvious things" that stick out....but the most obvious is this:

That "second peak" during the fall....when the Arctic was at its minimum AND the Antarctic was at its "maximum for the year".........is SOOOOOO much lower than the "normal".  Of course, it was a combination of the 2nd lowest Arctic minimum....PLUS....a low Antarctic maximum.  It will be fascinating to see if it is significantly below the level from LAST February during the Antarctic minimum.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 11, 2016, 04:35:06 AM
For Dec. 10th JAXA has posted 9,398,098 km2 for SIE around Antarctica.

Down by 322,239 km2.

  We started this month with 11,508,508 km2. More than 2 million km2 gone in 9 days.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Carex on December 11, 2016, 06:18:13 PM


The value for December 7 is 10,166  Dec 10 is 9,398 Mn km2.

If we want to keep the first place when 2017 begins we need to see another drop of about 4,2  3.4 Mn km2. The lowest value on record at New Year is 5,967 Mn km2 which was reached by January 1 in 1980. That means that we need to lose about 175K 163k every day. Should be a tough mission to fulfill despite that we are lowest on record today, but certainly not impossible.

Getting easier every day (so far).


Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 11, 2016, 06:31:14 PM
Getting easier every day (so far).

Thanks for the update.... :)

We are going to be in the age of "expect the unexpected" for many decades I'm afraid.  And by unexpected....I mean unexpectedly MORE melt.  At what level do the scientists go "oh shit"....this is REALLY BAD NEWS (I would assert that many are already there....and others will get their soon).

Momentum is a powerful thing....
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 11, 2016, 07:33:30 PM
Carex, I may be wrong, but I think you might be comparing JAXA numbers to NSIDC numbers.  LMV usually posts NSIDC. These have been running pretty close lately, but not the same.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 12, 2016, 04:52:19 AM
For Dec. 11th JAXA  has posted 9,078,802 km2 for SIE around Antarctica.

Down by 319,296 km2.

Wondering now how many of these triple century drops does December have in store. We might have to start abbreviating them as tcd's.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on December 12, 2016, 05:34:02 AM
To me it would seem that there are not many left, unless the area of rather solid ice north of the Ross Ice Shelf loses its integrity.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 12, 2016, 06:04:46 AM
There are huge areas(pics below) of ice in bad shape.Some of these patches probably meet the minimum percentage to be counted, making them seem to disappear even faster. It will be interesting to see what happens to Weddell Sea, which always seems to hold out to the end.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 12, 2016, 08:33:44 PM
More than 800K sea ice gone in just 3 days.

The NSIDC values were for

December 9:   -178K
December 10: -262K
December 11: -367K

and we are now down to 9,043 Mn km2. The 5-day average is at 9,628 Mn km2. Still, the 5-day average needs to drop another 3,3 Mn km2 until December 30 to remain lowest on record. That means we need to see roughly another 165K drop every day now.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 12, 2016, 09:19:48 PM
and we are now down to 9,043 Mn km2. The 5-day average is at 9,628 Mn km2. Still, the 5-day average needs to drop another 3,3 Mn km2 until December 30 to remain lowest on record. That means we need to see roughly another 165K drop every day now.

At 200K a day....that could "go quickly".  That would be slightly over 4 million (IF.....that 200K per day came to fruition).  Looking at prior years....it looks like we have about 10 days of REALLY STEEP LOSES....followed by another 10+ days of losses not quite as steep...but still "plenty steep".

A 3.5 - 4.0+ million loss is "doable" I'm afraid.....  Again, we find ourselves in the land of "unexpected happenings"....where the previously unthinkable....actually happens.

 
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on December 13, 2016, 01:21:02 AM
i think that the extre huge amount of blue instead of white surface will make it very probably that this continues. even within extent area there is a lot of dark blue that would absorb a lot of energy that was reflected in earlier years.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 13, 2016, 04:47:56 AM
For Dec. 12th JAXA has posted 8,769,622 km2 for SIE around Antarctica.

Down by 309,180 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on December 13, 2016, 05:22:00 AM
wow!
Title: Re: Sea Ice Extent around Antarctica
Post by: dingojoe on December 13, 2016, 05:51:27 AM
For all the attention on the Weddell side, a week to 10 days ago it was plausible for the Ross side to start lagging in melt.  There was a large dense pack and the polynya along the front of the Ross Ice Shelf wasn't especially large for the first week of Dec.  Well, the polynya has expanded quite rapidly over the last 10 days and while the pack on the East side is still large it's become much more pockmarked.  A full melt out of the Ross Sea (which doesn't always occur) seems much more likely now than 10 days ago.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tor Bejnar on December 13, 2016, 12:36:07 PM
I understand that most Antarctic sea ice is first year ice, so even as sea ice loss is earlier/faster than ever this year, by late summer (austral) other years are sure to 'catch up'.  Early melt will cause some amount of extra stresses on the ice systems due to diminished albedo and extra waves, though, I'm sure.  With the oceanic heat that is melting glacial tongues and (probably) ice shelves 'from the bottom' in recent years (decades), will the extra surface forces help foster some shelf or glacier collapses? (Or do the surface issues pale compared with the deep down ones?)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 13, 2016, 02:08:13 PM
I understand that most Antarctic sea ice is first year ice, so even as sea ice loss is earlier/faster than ever this year, by late summer (austral) other years are sure to 'catch up'.  Early melt will cause some amount of extra stresses on the ice systems due to diminished albedo and extra waves, though, I'm sure.  With the oceanic heat that is melting glacial tongues and (probably) ice shelves 'from the bottom' in recent years (decades), will the extra surface forces help foster some shelf or glacier collapses? (Or do the surface issues pale compared with the deep down ones?)
I posted an article in the What's New in Antarctica thread yesterday. They now have found out that Antarctic land ice is honeycombed with sub-surface lakes and streams much the same as Greenland. The problem is that some of these lakes run from land ice out to and maybe into shelves. So, they fear that when shelves break off, the lakes will dump all the water from even what's held under land ice. Obviously, this makes the whole situation less stable than anyone knew.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 13, 2016, 02:24:54 PM
December 9:   -178K
December 10: -262K
December 11: -367K

Adding in the loss from the 12th of 309K......Antarctica has now lost an area the size of California AND Texas...COMBINED for that 4 day period. 

https://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 13, 2016, 04:22:13 PM
I am starting to think that a lot of this accelerated melt of sea ice is from sst's. There is warmer waters very close by and the ocean is know for being rough around Antarctica.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 14, 2016, 04:25:45 AM
For Dec. 13th, JAXA has posted 8,519,734 km2 for SIE around Antarctica.

Down by 249,888 km2.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Pmt111500 on December 14, 2016, 04:53:52 AM
For Dec. 13th, JAXA has posted 8,519,734 km2 for SIE around Antarctica.

Down by 249,888 km2.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)

That looks like the Weddell Gyre has plenty of heat surfacing. Where this heat has come about is a good question, if someone knows please inform... I haven't followed Southern Ocean so well I could say if this is the sole reason for large drops and continued deficit of ice compared to normal, but it's one possibility.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 14, 2016, 05:14:01 AM
That is what I was looking at in post 160. How close the warm surface waters are, in the first image. Then the waves in the second image, which could bring in warm waters from nearby surface. Not saying this is the sole source, but a contributor. You will note that where the ice is gone wave action is moving in.
Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on December 14, 2016, 02:42:19 PM
I've been looking at this for a while, I'm begining to suspect that the Agulas cuurrent has filled the Agulas basin and is backed up past the point of breakout, mainly for the lack of other ideas. I can't think of any test to falsify it, nor any real evidence that it's true. I've animated the shown product/dataset/variables back at http://marine.copernicus.eu/services-portfolio/access-to-products/ (http://marine.copernicus.eu/services-portfolio/access-to-products/) and the temp. at various depths and it certainly appears to be melting from below, which could mean the local Weddel sea/Queen Mauds land ice shelves are in danger this summer. Animation icon bottom left, I ran it from 11/13 2fps.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FsPdnv%2Ff147cf5cca.jpg&hash=b56788b94186c6be23791c402d8ae720)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FsPdpP%2Fbe9e72e5f7.jpg&hash=10ec0d2cbe772098d6d8b196fdce5549)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 15, 2016, 05:08:03 AM
For Dec. 14th JAXA has posted 8,278,712 km2 for SIE around Antarctica.

Down by 241,022 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 15, 2016, 05:51:00 AM
The sea ice in Weddell sea has, as far back as I could tell, always held on to the end of melt season.
Maybe the Peninsula served to protect it or something. This year it is already showing early signs that it may not fare so well.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 15, 2016, 06:18:23 PM
For December 14, NSIDC reports a drop of -259K.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 15, 2016, 07:27:11 PM
For December 14, NSIDC reports a drop of -259K.

Average for the last 7 days is 266K per day (including a single day of 178K).

We have blown through 1,866,000 sq. kilometers in last 7 days.

This actually looks to be only a slightly "steeper" angle of descent than normal.  What WILL be interesting to me....is how long will this go on....and where will it end up?  Will it be a new record low by a little bit...or will it blow it away?  Right now...it looks like we are still about 5 standard deviations BELOW the mean for this time of year.

   
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on December 15, 2016, 07:28:41 PM
@ tigertown......re Weddell Sea ....my understanding is that the peninsula protects it from the prevailing westerly winds
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on December 15, 2016, 11:09:45 PM
@ tigertown......re Weddell Sea ....my understanding is that the peninsula protects it from the prevailing westerly winds

yes and the wave action and the mixing that comes with it. it's a very normel "lee" phenomenon" as it happens quite often, just that this is a big one and the result is quite obvious.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tealight on December 15, 2016, 11:30:36 PM
@Buddy

A new record low is of course highly likely, but the difference to other years will become smaller. The average minimum is around 2.88 million km2 and we are currently 2.4 million km2 below the average. An extent of only 0.4-0.5 million km2 is pretty much impossible.

For area the minimum would have to be negative to keep the current anomaly.
Title: Re: Sea Ice Extent around Antarctica
Post by: wehappyfew on December 16, 2016, 01:40:23 AM
I can see the next denier talking point...

"Antarctic negative anomaly diminishes at record pace!!! New Ice Age starting????!!!!11!!???"


Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 16, 2016, 01:59:02 AM
@Tealight

I pretty much agree with you.  I expect a record low....and I don't expect it to end up at .4 or .5 in Feb.  Although I would caution about using phrases like "pretty much impossible".  We are now entering a period of time over the next few years where we have a pretty good chance of being "shocked" from time-to-time by things that we thought were nearly impossible.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 16, 2016, 04:23:38 AM
For Dec. 15th JAXA has posted 8,047,850 km2 for SIE around Antarctica.

Down by 230,862 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on December 17, 2016, 01:58:06 PM
Lowest years of the 1973-2016 time series (2016 updated until December 16th):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F2478%2Flow_ant_pzu4.PNG&hash=698b776e04ae36a424cf02a92c514e6b)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 18, 2016, 08:40:28 AM
For Dec. 17th JAXA has posted 7,685,353 km2 for SIE around Antarctica.

Down by 362,497 km2 from that of the 15th.
Title: Re: Sea Ice Extent around Antarctica
Post by: andy_t_roo on December 18, 2016, 09:36:10 PM
Given that the ice melts back to the coast in many areas, even on an normal year, is anyone able  to split out the area graphics by region, or longitude?

This would allow the discussion to be split into 'the area was probably going to melt anyway so what does extended exposure to sea temps for the coast/ glaciers mean? '  and 'will the higher rate of melting mean this area will melt?'
Title: Re: Sea Ice Extent around Antarctica
Post by: Rattle on December 18, 2016, 11:09:30 PM
For area the minimum would have to be negative to keep the current anomaly.

Should there be a thread monitoring loss of land ice?

In seriousness I agree that the anomaly will have to reduce eventually, it looks to me like the chart is tracking closely with previous years but about 1 week early.
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on December 18, 2016, 11:19:43 PM
Just keep an eye on Weddell as that generally holds onto a lot of ice but there is already open water there and those 'fohn winds' might also mess with the ice closest to the peninsula as summer progresses?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 19, 2016, 06:46:57 AM
For Dec. 18th JAXA has posted 7,529,128 km2 for SIE around Antarctica.

Down by 156,225 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on December 19, 2016, 09:50:43 AM
There seems to be a slight possibility of catching up with other years by the end of the year.
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on December 19, 2016, 01:29:35 PM
The problem , to me, is not the final figures ( even though I think that they will be low) but the heat that the lack of ice has been able to be taken up, compared to years when ice albedo was higher due to there being more ice present?

We are post Nino and a number of folk are looking to see Global temps fall as they did after the 98' Super Nino that had a following Nina until 2001? Global Temps are already appearing to recover from the post nino dip and I think Southern ocean temps will be playing a part in that if not the anomalous temps over both Poles?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 19, 2016, 01:50:33 PM
JAXA just updated there imaging.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on December 19, 2016, 01:54:40 PM
Winter rainfall over Australia was extreme this year ...possibly caused by the southern ocean lows moving slightly northward
http://www.bom.gov.au/tmp/cc/rranom.aus.0608.58473.hires.png (http://www.bom.gov.au/tmp/cc/rranom.aus.0608.58473.hires.png)
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on December 19, 2016, 02:00:01 PM
followed by much lower average Spring temperatures over Australia .....admittedly only down to the long term average

http://www.bom.gov.au/tmp/cc/tmean.aus.0911.29881.hires.png (http://www.bom.gov.au/tmp/cc/tmean.aus.0911.29881.hires.png)
Title: Re: Sea Ice Extent around Antarctica
Post by: andy_t_roo on December 19, 2016, 09:42:10 PM
Winter rainfall over Australia was extreme this year ...possibly caused by the southern ocean lows moving slightly northward
http://www.bom.gov.au/tmp/cc/rranom.aus.0608.58473.hires.png (http://www.bom.gov.au/tmp/cc/rranom.aus.0608.58473.hires.png)
Sorry kiwichick16,  but both your links are 'page not found'
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 20, 2016, 05:33:06 AM
For Dec. 19th JAXA has posted 7,313,591 km2 for SIE around Antarctica.

Down by 215,537 km2.

Edit: Warning! Big drops coming up. There are huge areas of ice that have degraded very rapidly, but still have enough concentration to count in SIE. When these go, they will probably go fast.
Example.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 20, 2016, 07:41:51 AM
Weddell sea ice from Dec. 1st til now plus forecast to the 29th
Click image for action
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on December 20, 2016, 12:44:55 PM
Good work TT. I've been looking at these too
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D598535.15625%252C2483691.40625%252C4009179.6875%252C4964160.15625%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Dso%26amp%3Btime%3D2016-12-19T12%25253A00%25253A00.000Z%26amp%3Belevation%3D-0.49402499198913574%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D27.204199%252C34.934536%26amp%3BdisplayScaleRange%3D27.204199%252C34.934536%26amp%3Bopacity%3D1%26amp%3Bbbox%3D598535.15625%252C2483691.40625%252C4009179.6875%252C4964160.15625%26amp%3BlayerTitle%3Dsea_water_salinity%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32761%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dm%26amp%3Bunits%3D1e-3%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_south_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_south_pole_no_ocean&hash=d716ffd34a1a8207ee7a7d8201a90104)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D-1869531.25%252C1138037.109375%252C4951757.8125%252C6098974.609375%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Dthetao%26amp%3Btime%3D2016-12-19T12%25253A00%25253A00.000Z%26amp%3Belevation%3D-0.49402499198913574%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D-2.404523%252C2.8807948%26amp%3BdisplayScaleRange%3D-2.404523%252C2.8807948%26amp%3Bopacity%3D1%26amp%3Bbbox%3D-1869531.25%252C1138037.109375%252C4951757.8125%252C6098974.609375%26amp%3BlayerTitle%3Dsea_water_potential_temperature%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32761%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dm%26amp%3Bunits%3Ddegrees_C%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_south_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_south_pole_no_ocean&hash=17b1a054eb44b5d81990fe712acece31)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D598535.15625%252C2483691.40625%252C4009179.6875%252C4964160.15625%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Dvo%26amp%3Btime%3D2016-12-19T12%25253A00%25253A00.000Z%26amp%3Belevation%3D-0.49402499198913574%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D-0.40040284%252C0.2624592%26amp%3BdisplayScaleRange%3D-0.40040284%252C0.2624592%26amp%3Bopacity%3D1%26amp%3Bbbox%3D598535.15625%252C2483691.40625%252C4009179.6875%252C4964160.15625%26amp%3BlayerTitle%3Dnorthward_sea_water_velocity%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32761%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dm%26amp%3Bunits%3Dm%2Bs-1%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_south_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_south_pole_no_ocean&hash=43304546e70b3689db84c8ba85921f21)
I'll be surprised if all of the ice shelves in the area remain intact.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 20, 2016, 03:46:14 PM
That's almost shocking that 49 cm down makes that much difference. The temperatures really surprised me. I probably checked the surface a dozen times, wondering why everything was happening so fast.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 21, 2016, 05:39:14 AM
For Dec. 20th JAXA has posted 7,149,895 km2 for SIE around Antarctica.

Down by 163,696 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on December 21, 2016, 07:54:37 AM
There seems to be a slight possibility of catching up with other years by the end of the year.
Welp, that slim chance is gone now.
Title: Re: Sea Ice Extent around Antarctica
Post by: Adam Ash on December 21, 2016, 11:20:18 AM
Just keep an eye on Weddell as that generally holds onto a lot of ice but there is already open water there and those 'fohn winds' might also mess with the ice closest to the peninsula as summer progresses?

I imagine that winds blowing west-to-east across the peninsula into the Weddell Sea will push ice away from the coast.  The already exposed water between the ice shelves and the free ice will then be pushed away from the coast leading to a turn over - with the deeper (warmer?) water being pulled up to replace it.  Which will further erode both the ice shelf and the adjacent sea ice - opening more water surface to the roll-over effect... etc.  A pretty feedback loop indeed.
Title: Re: Sea Ice Extent around Antarctica
Post by: georged on December 21, 2016, 11:26:49 AM

I imagine that winds blowing west-to-east across the peninsula into the Weddell Sea will push ice away from the coast.  The already exposed water between the ice shelves and the free ice will then be pushed away from the coast leading to a turn over - with the deeper (warmer?) water being pulled up to replace it.  Which will further erode both the ice shelf and the adjacent sea ice - opening more water surface to the roll-over effect... etc.  A pretty feedback loop indeed.

I was thinking about exactly that. When fresh melt is of a sufficient volume it pulls in warm water, creating a giant heat export pump. Under certain conditions, this could be self sustaining and create an ongoing feedback.
Title: Re: Sea Ice Extent around Antarctica
Post by: Jim Hunt on December 21, 2016, 11:56:11 AM
A recent NASA article about Antarctic (& global!) sea ice:

http://earthobservatory.nasa.gov/IOTD/view.php?id=89280 (http://earthobservatory.nasa.gov/IOTD/view.php?id=89280)

It remains to be seen how much Antarctic sea ice will melt during the remainder of the season; sea ice usually reaches its annual minimum extent in February. In some places around the continent, sea ice can melt completely before starting the annual cycle of refreezing.

In recent years, notably from 2012 to 2014, the period of refreezing has culminated in record-high maximum extents. On an annual basis, the total Antarctic sea ice extent has increased about 1 percent per decade since 1979. Still, the long-term trend still shows a global decline in sea ice.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 21, 2016, 04:52:55 PM
NSIDC reports a mammoth century break today with a 378K drop.

For the dates the drops were

December 15: 125K
December 16: 205K
December 17: 114K
December 18: 149K
December 19: 57K
December 20: 378K

The daily value for December 20 is now down to 7,167 Mn km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on December 21, 2016, 07:34:17 PM
Updated until Dec. 20th

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F6474%2Fantarctic_jzk1.PNG&hash=707ef58d29ffb2e3d6b60eea2b2be094)

Title: Re: Sea Ice Extent around Antarctica
Post by: frankendoodle on December 21, 2016, 07:40:45 PM
I usually only follow Arctic Sea Ice March through September but this year (for obvious reasons) has me keenly interested in Antarctica. 

The JAXA measurement for December 20th 2016 is 3,164,640 km2 lower than the 2010-2015 average for this date & 2,289,662 km2 lower than the 2000's average for 12/20.

I am starting to think that Antarctic Sea Ice might fall to or below one million km2 in February.
What is everyone's opinion on this?
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on December 21, 2016, 08:27:15 PM
I usually only follow Arctic Sea Ice March through September but this year (for obvious reasons) has me keenly interested in Antarctica. 

The JAXA measurement for December 20th 2016 is 3,164,640 km2 lower than the 2010-2015 average for this date & 2,289,662 km2 lower than the 2000's average for 12/20.

I am starting to think that Antarctic Sea Ice might fall to or below one million km2 in February.
What is everyone's opinion on this?

- as to 1M i agree as to the possibility being real

- as to only watching north (because it was more interesting and because most of us live north of the equator) i think this is not the right approach. after all we have one planet we live on and space ship earth is definitely one system and it's sections cannot and should not be artificially seen separately. just another one of those splitting everything up into tiny niches where some can
play know it all and in the process mankind is using the bigger picture that is so much needed to make good decisions.

to make this clear, i don't mean you, your post just gave me the trigger to repeat this whenever an opportunity occurs because IMO it's part of the problem that we so much specialize and in the process divide things that in reality belong very much together.

cheers.
Title: Re: Sea Ice Extent around Antarctica
Post by: frankendoodle on December 21, 2016, 11:27:29 PM
I usually only follow Arctic Sea Ice March through September but this year (for obvious reasons) has me keenly interested in Antarctica. 

The JAXA measurement for December 20th 2016 is 3,164,640 km2 lower than the 2010-2015 average for this date & 2,289,662 km2 lower than the 2000's average for 12/20.

I am starting to think that Antarctic Sea Ice might fall to or below one million km2 in February.
What is everyone's opinion on this?

- as to 1M i agree as to the possibility being real

- as to only watching north (because it was more interesting and because most of us live north of the equator) i think this is not the right approach. after all we have one planet we live on and space ship earth is definitely one system and it's sections cannot and should not be artificially seen separately. just another one of those splitting everything up into tiny niches where some can
play know it all and in the process mankind is using the bigger picture that is so much needed to make good decisions.

to make this clear, i don't mean you, your post just gave me the trigger to repeat this whenever an opportunity occurs because IMO it's part of the problem that we so much specialize and in the process divide things that in reality belong very much together.

cheers.

I agree whole heatedly with what you posted. I am interested in Antarctica itself and it's mass losses over the last decade. What I love about both the poles is that they are polar opposites of each other both figuratively and literally :)
I have not been interested in Antarctic Sea Ice because those numbers have been very, very flat over the last 30 years, even though deniers love to talk about the tiny increase over time that is well within one SD. But you're right. If one is studying wildfire rates they should do so globally and not just those on their continent.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 22, 2016, 04:36:41 AM
For Dec. 21st JAXA has posted 7,008,635 km2 for SIE around Antarctica.

Down by 141,260 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 23, 2016, 06:40:36 AM
Jaxa updated their image already today, but not the extent chart quite yet.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 24, 2016, 04:37:26 AM
For Dec. 23rd JAXA has posted 6,701,414 km2 for SIE around Antarctica.

Down by 307,221 km2 since the 21st.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 25, 2016, 04:41:08 AM
For Dec. 24th JAXA has posted 6,441,674 km2 for SIE around Antarctica.

Down by 259,740 km2.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 26, 2016, 04:31:46 AM
For Dec. 25th  JAXA has posted 6,285,842 km2 for SIE around Antarctica.

Down by 155,832 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on December 26, 2016, 09:16:54 PM
Merry Christmas to the Antarctic in the form of a smaller drop! ;D
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 27, 2016, 04:36:51 AM
For Dec. 26th JAXA has posted 6,131,715 km2 for SIE around Antarctica.

Down by  154,127 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 28, 2016, 04:41:10 AM
For Dec. 27th JAXA has posted  5,988,099 km for SIE around Antarctica.

Down by 143,616 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 28, 2016, 04:01:51 PM
For Dec. 28th JAXA has posted 5,891,625 km2.

Down by 96,474 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 28, 2016, 04:06:37 PM
We only have till sometime in February until the melting ends....and February will likely be "flatish"....so one more month of any significant melting.....and then the attention turns to the North...

Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 28, 2016, 04:14:47 PM
Buddy & Co: in some years the minimum occurrs in the beginning of March. But most likely we will see the minimum during the last week in February.

Btw, NSIDC reports a SIE of 6,061 Mn km2 for December 27. Should cross the 6 Mn mark by tomorrow.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on December 28, 2016, 04:56:01 PM
Will be interesting to see if we get below 16K2 in COMBINED sea ice (per Wipneus' graph). 

We really DO have two fascinating ice sheets to watch play out.  The Antarctic looks like it will REALLY have some significant "issues" in the next  1 - 5 years as the ice shelves continue to melt and crack away.....and the Arctic is looking REALLY WEAK on the Atlantic side and melt season won't start for another 6 - 8 weeks.

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 28, 2016, 05:08:15 PM
I expect some huge drops ahead, simply because there are large area of ice already in bad shape. These are still showing up area wise because the concentration is above the threshold value.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pi26 on December 28, 2016, 06:37:35 PM
We only have till sometime in February until the melting ends....and February will likely be "flatish"....so one more month of any significant melting.....and then the attention turns to the North...

With additional some hundret Petawatthours that heated into these waters, because we had since mid November always 1.5-2.0 M km2 less SIE than usual, melting ends probably in March or as soon it is done completly.

And I think REALLY, that not the antarctic and arctic will have issues in the next years, but we all.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on December 29, 2016, 05:29:41 PM
We only have till sometime in February until the melting ends....and February will likely be "flatish"....so one more month of any significant melting.....and then the attention turns to the North...

With additional some hundret Petawatthours that heated into these waters, because we had since mid November always 1.5-2.0 M km2 less SIE than usual, melting ends probably in March or as soon it is done completly.

And I think REALLY, that not the antarctic and arctic will have issues in the next years, but we all.

I'm not making any predictions now for February/March on the back of such unprecedented lead-in conditions, but I will be watching closely.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on December 30, 2016, 01:01:02 AM
Expect large drops in the remaining ice north of the Ross Ice Shelf starting shortly after new years. An extremely thick tropical plume of moisture from Australia is traveling with a low pressure down towards West Antarctica over the next few days and is predicted to deliver massive amounts of heat to the area of Antarctica around the Ross Ice Shelf and nearby areas in both the EAIS and WAIS.

Here, you can see the extremely anomalous plume of moisture, with large areas more than 6σ above average for precipitable water:
http://i.imgur.com/WKD5NG6.png (http://i.imgur.com/WKD5NG6.png)
https://dl.dropboxusercontent.com/u/45288313/RL%20mapps/aus20161229.000000_tpw.png (https://dl.dropboxusercontent.com/u/45288313/RL%20mapps/aus20161229.000000_tpw.png)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 30, 2016, 04:29:32 AM
For Dec. 29th JAXA has posted 5,812,645 km2 for SIE around Antarctica.

Down by 78,980 km2.

Water temps are generally up, in the open water areas surrounding Antarctica.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on December 30, 2016, 07:09:31 PM
Another 138K down. We are now at 5,826 Mn km2 for December 29. It's now very likely that the 5-day average for the first time will drop below 6 Mn km2 as 2016 ends. Interesting to see that JAXA and NSIDC daily values are so close to each other, only about 14K difference between them.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on December 31, 2016, 04:36:11 AM
For Dec. 30th JAXA  has posted 5,687,501 km2 for SIE around Antarctica.

Down by 125,144 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: CalamityCountdown on December 31, 2016, 07:01:32 PM
If I make like a climate science denier, and cherry pick my dates, the decline is Antarctic sea ice extent can be presented in dramatically different fashions. As of December 30, SIE was 5.941 million square km. That's only down 7% in 37 years (versus 1979 - 6.376 square km). But if the comparison is versus 2013 SIE of 9.292 million square km, then it's down 36% in just 3 years.
Source - http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/)
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on December 31, 2016, 07:02:36 PM
Lowest years of the 1973-2016 time series (updated until 2016/12/30):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F2373%2Flowest3012_oqi0.PNG&hash=0c2ac04e71ea1de15565fa4330e08505)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 01, 2017, 05:04:31 AM
For Dec 31st JAXA has posted 5,556,992 km2 for SIE around Antarctica.

Down by 130,509 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on January 02, 2017, 01:20:29 AM
If I make like a climate science denier, and cherry pick my dates, the decline is Antarctic sea ice extent can be presented in dramatically different fashions. As of December 30, SIE was 5.941 million square km. That's only down 7% in 37 years (versus 1979 - 6.376 square km). But if the comparison is versus 2013 SIE of 9.292 million square km, then it's down 36% in just 3 years.
Source - http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/)

always a good move to expose the shady methods of the scamsters, thanks !  LOL

Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 02, 2017, 08:15:04 AM
NSIDC reported a value of 5,575 Mn km2 for December 31 while the 5-day average was 5,826 Mn km2, the absoutely lowest 5-day value on record.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 03, 2017, 04:38:57 AM
No SIE update from JAXA for a couple days now but they have updated the concentration map.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 03, 2017, 06:46:53 PM
While the Charctic NSIDC values for 2017 haven't been updated, the daily values from NSIDC have. The drops were for

January 1: -134K
January 2: -122K

The 5-day average is (manual estimate!): 5,573 Mn km2. The daily value for January 2 is now 5,319 Mn km2.

Of crucial importance for the final outcome of this melting season is what will happen to the sea ice in the Ross Sea. If it doesn't melt out virtually completely, I'm fairly confident that we won't break the minimum years.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 04, 2017, 05:41:01 AM
Since there are no numbers in from JAXA, I will just post an image updated through today.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: ArcticMelt on January 04, 2017, 07:22:30 PM
Charctic Interactive Sea Ice Graph

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 05, 2017, 04:30:23 AM
For Jan. 3rd JAXA has posted 5,148,723 km2 for SIE around Antarctica.
Edit:
And now JAXA has posted for Jan. 4th at 5,038,887 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 05, 2017, 04:43:19 AM

Of crucial importance for the final outcome of this melting season is what will happen to the sea ice in the Ross Sea. If it doesn't melt out virtually completely, I'm fairly confident that we won't break the minimum years.
Who knows? Here is what we do know.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 05, 2017, 03:56:20 PM
Thanks T-town for those insightful pics! :) Where do you find them?

As for today, another 129K drop was seen around Antarctica according to NSIDC, the same as yesterday.We are now down to 5,043 Mn km2.

By tomorrow, NSIDC will almost certainly report a SIE below 5 Mn km2.

//LMV
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 05, 2017, 04:37:42 PM
CMEMS. I learned about them from johnm33.
http://marine.copernicus.eu/services-portfolio/access-to-products/
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 05, 2017, 08:35:27 PM
Thanks dude! :) Really useful tool to look at the sea ice thickness around both poles :)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 06, 2017, 04:30:06 AM
For Jan. 5th JAXA has posted 4,968,665 km2 for SIE around Antarctica.

Down by 70,222 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 06, 2017, 11:59:58 AM
Not very surprising given the unusually low SIE numbers...

(https://nsidc.org/data/seaice_index/images/s_plot_hires.png)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 07, 2017, 04:46:03 AM
For Jan. 6th JAXA has posted 4,926,275 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on January 07, 2017, 01:58:21 PM
For Jan. 6th JAXA has posted 4,926,275 km2 for SIE around Antarctica.

2006 was 4.88 so now only 2nd lowest on record for date.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 08, 2017, 04:32:57 AM
For Jan. 7th JAXA has posted 4,830,950 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 08, 2017, 03:14:28 PM
For Jan. 6th JAXA has posted 4,926,275 km2 for SIE around Antarctica.

2006 was 4.88 so now only 2nd lowest on record for date.

The odd thing about that is that on NSIDC's Charctic tool 2017 is well below 2006 for that date. Anyone have a guess as to why the two measures would differ so much?
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on January 08, 2017, 04:38:02 PM
For Jan. 6th JAXA has posted 4,926,275 km2 for SIE around Antarctica.

2006 was 4.88 so now only 2nd lowest on record for date.

The odd thing about that is that on NSIDC's Charctic tool 2017 is well below 2006 for that date. Anyone have a guess as to why the two measures would differ so much?

as far as i know chartic is a 5 days average, hence since this is the second day only that we're above 2006 in the daily values, it would (will) take another day or two to show in that chart. ready to stand corrected, this is just what came into my mind while reading the question.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 08, 2017, 11:43:37 PM
2017, 01,  06,      4856000 sq km
2017, 01,  07,      4766000 sq km

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F9049%2Fantar17_7_ljx7.PNG&hash=85e89462bda11d71136e8bb3b316b741)



Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 09, 2017, 05:22:42 AM
For Jan. 8th JAXA has posted 4,732,309 km2 for SIE Around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 09, 2017, 06:20:52 AM
Small question: As and when Larsen C breaks off and breaks up, would I be right in thinking this would count as an increase in sea ice extent?
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 09, 2017, 05:51:41 PM
2017, 01,  07,      4766000 sq km
2017, 01,  08,      4694000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F2868%2Fantar17_8_qls6.PNG&hash=70708b1f6e8569fc61c8b60efe0a4c83)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 09, 2017, 06:04:26 PM
Small question: As and when Larsen C breaks off and breaks up, would I be right in thinking this would count as an increase in sea ice extent?
We have had similar discussions in the past. Some said yes and some said no. Personally, I would feel that it would be wrong to do so,as it would distort seasonal data. However after time went by and it broke up into smaller pieces and some, that didn't go out to open sea, got mixed in with the fresh ice from freeze season, it may become hard to distinguish it from the rest.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on January 09, 2017, 06:15:18 PM
The orange line in the picture is the possible minimum extent that could happen if the low-concentrated ice would melt completely. That would be about 2,1 mln sq km,a record low extent.
(https://pp.vk.me/c637122/v637122983/27e83/dMRX-IHIyjk.jpg)
Title: Re: Sea Ice Extent around Antarctica
Post by: FredBear on January 10, 2017, 02:03:13 AM
Small question: As and when Larsen C breaks off and breaks up, would I be right in thinking this would count as an increase in sea ice extent?
5000km^2 is an insignificant area to add to sea ice area, but 350m thickness represents a lot of thermal capacity - circa 1500 gigatonnes to melt (and if it were to shatter completely that comes to 1.75million km^2 @1m thickness). (In round numbers!)

P.S. I have often wondered how much the disintegration of the Larsen B ice shelf (and subsequent acceleration of surrounding glaciers) has contributed to the amount of sea ice in the Weddell Sea. (Area that was lost 3250km^2, + glaciers flowing up to 10 times faster, still giving 22-40 gigatonnes of ice in 2006?). Plus the increased albedo of ice/snow instead of open water which was visible before the collapse in 2002.
Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on January 10, 2017, 04:14:35 AM
Small question: As and when Larsen C breaks off and breaks up, would I be right in thinking this would count as an increase in sea ice extent?
5000km^2 is an insignificant area to add to sea ice area, but 350m thickness represents a lot of thermal capacity - circa 1500 gigatonnes to melt (and if it were to shatter completely that comes to 1.75million km^2 @1m thickness). (In round numbers!)

P.S. I have often wondered how much the disintegration of the Larsen B ice shelf (and subsequent acceleration of surrounding glaciers) has contributed to the amount of sea ice in the Weddell Sea. (Area that was lost 3250km^2, + glaciers flowing up to 10 times faster, still giving 22-40 gigatonnes of ice in 2006?). Plus the increased albedo of ice/snow instead of open water which was visible before the collapse in 2002.

However the rate of heating of that mass will depend on its exposed  surface area and the heat transfer coefficient at the interface with i) air and 2) water. So that enormous heat capacity will be slowly accessible...
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 10, 2017, 04:35:56 AM
For Jan. 9th JAXA has posted 4,613,991 km2 for SIE around Antarctica.

Down by 118,318 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 10, 2017, 04:35:44 PM
2017, 01,  08,      4694000 sq km
2017, 01,  09,      4597000 sq km

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F4972%2Fantar17_9_wee8.PNG&hash=c5def24a1d634611fef157bac423c0a1)



Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 11, 2017, 01:48:03 PM
No SIE update yet, but only the image.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on January 11, 2017, 02:40:23 PM
One thing to keep in mind....especially this year with the Antarctic sea ice area at record low levels....is that the southern oceans will be the first place that is impacted by the low level of sea ice.

I watch SST's pretty closely....and I will continue watching SST's going forward for the next few months.  This year should have provided a nice "punch" of heat into the southern oceans becaue of the lack of sea ice around Antarctica.  Below is the SST from Jan 9th.  The warm anomalies in the southern oceans have been intensifying over the past 4 - 6 weeks. 

 
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 11, 2017, 05:52:23 PM

2017, 01,  09,      4597000 sq km
2017, 01,  10,      4426000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F2321%2Fantar17_10_hce8.PNG&hash=8234b13b7909ff10e81813c72991e437)

Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 11, 2017, 06:12:18 PM
After a 171K drop we are now down to 4,426 Mn km2. We are still lowest on record but the margin to other years have shrunken a lot and it's not impossible that we will lose the first place in a few days or so.

Most of the sea ice in the Ross Sea is 0,7 m or less, but with a onth left I find it quite hard to believe that all of that ice will melt out. So my forecast is that we will get a very low minimum but not a record low one.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on January 12, 2017, 07:58:03 AM
IJIS for today and yesterday came out, huge double century drop to 4.27, I'll let Tigertown post the detailed numbers. The Ross sea ice is definitely going fast now...
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 12, 2017, 10:18:09 AM
Thanks Darvince. I just checked a couple hours ago, but I guess it was like a watched pot trying to boil.

For Jan. 11th JAXA has posted 4,267,245 km2 for SIE around Antarctica.

Down by 346,746 km2 from the extent on the 9th.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on January 12, 2017, 10:21:51 AM
Weather conditions and forecast are adverse for melting only in Bellingshausen sea because of colder air. In Weddel sea ice is spreading but melting continues. Other areas melt rapidly. I think the ice in the Ross sea will melt out completely, also there will be significant ice loss in Casey-Dumont. Everything goes to the new record low extent
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 12, 2017, 04:48:58 PM
If the ECMWF 00z op run is correct, then the sea ice in Ross Sea will be hammered by a 960-965 hpa cyclone in 48 hours. Most of the ice is about 0,5-0,7 m thick (see attached pic, courtesy Copernicus) there so the cyclone should have potential to do damage to the ice there.

One question of importance is how many km2 that area make up? Anyone who knows?

And does anyone know where I find the forecast that shows the evolution of the sea ice thickness around Antarctica?

NSIDC reports a drop of 150K today and we are now at 4,426 Mn km2. We are still lowest on record.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 12, 2017, 05:24:28 PM
Right at the top of your image, where it says "Time" is where you adjust to the future date. It will go about a week or so forward at most.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 12, 2017, 06:50:19 PM
Thanks again Tigertown :) Well, if the forecast from Copernicus holds then this is what will remain of the big sea ice "block" in the Ross Sea by January 21:

Title: Re: Sea Ice Extent around Antarctica
Post by: frankendoodle on January 12, 2017, 09:53:07 PM
JAXA SIE data:

1997 (record low year) took 36 days to go from 4.25 M km2 (1/13) to 2.25 km2 (2/19). That's an average of ~55K km2 per day.

If 2017 hits it's minimum on 2/19 then it only needs an average of ~52K km2 per day to tie. Or if it melts at the same rate as 1997 will hit a minimum of ~2.08M km2 on 2/19.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 13, 2017, 05:28:00 AM
For Jan. 12th JAXA has posted 4,100,561 km2 for SIE around Antarctica.

Down by 166,684 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on January 13, 2017, 06:02:41 AM
@ tigertown.....so that's 3 days times 50 ish
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 13, 2017, 09:02:09 AM
Actually, that is just a one day drop.
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on January 13, 2017, 12:03:50 PM
@ tigertown ....yes .....sorry ....I was referring to the post by Frankendoodle .....saying 50 thousand ish per day would take us to a new record low

Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 13, 2017, 01:11:39 PM
Yes, although we can expect this curve to flatten out as it nears bottom.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 13, 2017, 02:20:26 PM

2017, 01, 10,      4426000 sq km
2007, 01, 11,      4276000 sq km
2007, 01, 12,      4026000 sq km

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F1827%2Fantar17_12_zup1.PNG&hash=428e267c5d4b4ec1f88345c2ca1a674d)





Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on January 13, 2017, 06:51:27 PM
Like the curve is supposed to flatten as the year progresses. Methinks both poles have been mocking us for some time.
Title: Re: Sea Ice Extent around Antarctica
Post by: charles_oil on January 13, 2017, 09:40:11 PM
Diab - I assume these are 2017 daily figures (not 2007) ?  Rather than the 5 day avg on Chartic
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 13, 2017, 10:39:19 PM
Diab - I assume these are 2017 daily figures (not 2007) ?  Rather than the 5 day avg on Chartic
Those are the daily numbers.
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/south/daily/data/SH_seaice_extent_nrt_v2.csv
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 14, 2017, 04:38:40 AM
For Jan. 13th JAXA has posted 3,949,764 km2 for SIE around Antarctica.

Down by 150,797 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 14, 2017, 09:41:54 PM
Diab - I assume these are 2017 daily figures (not 2007) ?  Rather than the 5 day avg on Chartic
Yes, 2017 NSIDC daily numbers (2007 was a typo)


A smaller drop today:

2017, 01, 12,      4026000 sq km
2017, 01, 13,      3980000 sq km

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F4317%2Fantar17_13_tpk6.PNG&hash=3dea39ff901adf86d37ae6dfa19a576c)


Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 15, 2017, 04:24:27 AM
For Jan. 14th JAXA has posted 3,784,027 km2 for SIE around Antarctica.

Down by 165,737 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: frankendoodle on January 15, 2017, 05:51:19 AM
Using 1997 as a template (rate of melt and minimum date) 2017's minimum would occur on 2/19 and be a record 1.95M km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on January 15, 2017, 08:40:23 AM
SSTs are warmer than usual and continue to heat up.The melting season could be longer than usual as well as weaker start of the freezing season
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on January 15, 2017, 03:52:22 PM
SSTs are warmer than usual and continue to heat up.The melting season could be longer than usual as well as weaker start of the freezing season

STRONGLY agree.  The southern portions of ALL 3 MAJOR OCEANS have had their warm anomalies intensify AND broaden over the last 8 weeks.

The start of the Antarctic melt season was EARLY AND EMPHATIC.  I would NOT be surprised to see the melt season in the Antarctic last longer than usual.  We all know...that over time, the melt seasons ARE getting longer the more the planet warms.  But this year especially with such low sea ice levels in Antarctica.....there has to be a lot more heat that "should" push the melt season longer than normal (other things being equal).
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on January 15, 2017, 04:11:42 PM
SSTs are warmer than usual and continue to heat up.The melting season could be longer than usual as well as weaker start of the freezing season

Early melt - albedo loss - warmer SSTs (from Tealight's site)


Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 15, 2017, 06:04:52 PM
2017, 01, 13,      3980000 sq km
2017, 01, 14,      3838000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F3367%2Fantar17_14_qmc1.PNG&hash=c187f2ac5d6eea73623f1a93ac311848)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 16, 2017, 05:54:28 AM
For Jan. 15th JAXA has posted 3,639,804 km2 for SIE around Antarctica.

Down by 144,223 km2.

JAXA has not updated imagery in a few days, so here is two images from CMEMS
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 16, 2017, 08:41:29 AM
Lot of thin ice still there to melt, especially in the rocking-horse shaped bit well offshore on the pacific side. Also, another poll category dropped.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on January 16, 2017, 10:55:34 AM
Lot of thin ice still there to melt, especially in the rocking-horse shaped bit well offshore on the pacific side. Also, another poll category dropped.

you say it, looking at those images one could think that we could end up somewhere not much above zero ice and then looking at the graphs trajectories it does not look much better.

honestly i don't believe that we go much below 2M but still it's and eerie scenario all over both poles. globally we have passed all minimums and are heading straight for some kind of ice collapse. i just hope we shall get a cool and cloudy summer up north, else we shall be in for trouble.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 16, 2017, 06:36:46 PM

2017, 01, 14,      3838000 sq km
2017, 01, 15,      3642000 sq km

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F3387%2Fantar17_15_rfq3.PNG&hash=132c1c491c13ab2907b4a788c0981641)

Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 16, 2017, 07:04:11 PM
The only two areas that have a decent chance to melt out significantly until the minimum is reached is Ross Sea and the adjacent Somov Sea. In the Weddell Sea most of the ice is fairly "thick" with about more than 1.0 m which I seriously doubt wll melt very much until minimum. However, compaction might happen and lower the SIE number.

Attached pics are the modelled sea ice thickness in the Ross and Somov Sea for Jan 16 and the forecast for Jan 25. Anyone who has a decent guess to stimate how many km2 we should lose up to Jan 25 due to the pics?

FYI, NSIDC 5-day average are now below 4 Mn km2 while the daily value is at 3,642 Mn km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on January 16, 2017, 07:05:44 PM
honestly i don't believe that we go much below 2M but still it's and eerie scenario all over both poles. globally we have passed all minimums and are heading straight for some kind of ice collapse. i just hope we shall get a cool and cloudy summer up north, else we shall be in for trouble.

I agree....although getting close to 1.5 is possible IF the ocean waters affect is greater than expected.  1.5 would be a REAL SHOCKER.... and I have to believe would pretty much scare the bejeebees out of many climate scientists.

Again....it's always hard to deal with levels that have never been seen before.  It's all just varying degrees of "unseen".

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 16, 2017, 07:38:46 PM
The waters around Antarctica will continue to warm in the coming days and may change the melt momentum.
CLICK IT
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on January 16, 2017, 08:34:06 PM
honestly i don't believe that we go much below 2M but still it's and eerie scenario all over both poles. globally we have passed all minimums and are heading straight for some kind of ice collapse. i just hope we shall get a cool and cloudy summer up north, else we shall be in for trouble.

I agree....although getting close to 1.5 is possible IF the ocean waters affect is greater than expected.  1.5 would be a REAL SHOCKER.... and I have to believe would pretty much scare the bejeebees out of many climate scientists.

Again....it's always hard to deal with levels that have never been seen before.  It's all just varying degrees of "unseen".

seconding every single word. perhaps we should come up (invent) a new abbreviation like:

ABRUPT SEA ICE LOSS = ASIL :-)

followed by an ASLR of course !
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 17, 2017, 05:33:42 AM
For Jan. 16th JAXA has posted 3,514,601 km2 for SIE around Antarctica.

Down by 125,203 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 17, 2017, 06:06:15 PM
For Jan. 16 NSIDC reports a drop of 149K down to 3,493 Mn km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 18, 2017, 05:30:50 AM
For Jan. 17th JAXA has posted 3,410,505 km2 for SIE around Antarctica.

Down by 104,096 km2.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 18, 2017, 07:20:56 AM
From the animation, most of the extent loss seems to be happening in the offshore ice in the Ross sea, rather than in the ice that's relatively fast to the shore of the rest of the continent. I wonder how far losing that completely would take us, and how much extent loss might slow down once it's gone.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 19, 2017, 05:25:28 AM
For Jan. 18th JAXA has posted 3,313,301 km2 for SIE around Antarctica.

Down by 97,204 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on January 19, 2017, 08:04:53 AM
30 days of melt season left??

@ 100,000 sq kms per day ??

=  zero sea ice  20 th February 2017  ??????????????????????????
Title: Re: Sea Ice Extent around Antarctica
Post by: budmantis on January 19, 2017, 11:13:57 AM
30 days of melt season left??

@ 100,000 sq kms per day ??

=  zero sea ice  20 th February 2017  ??????????????????????????

That's a lot of befuddled emojis kiwichick!

As January gives way to February, the rate of melt will most likely slow, due to reduced insolation. For the rest of January, assuming an average drop of 100,000 sq kms daily, we would be at 2.1 million sq kms. by February 1. Afterward, the average daily melt will likely slow, but the final number could be below 1.5 million sq kms.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on January 19, 2017, 11:26:25 AM
The average drop for the rest of the month should be rather slow compared to recent days as the area where the extent was dropping fast, the shattered and scattered ice north of the Ross Ice Shelf, is almost gone.
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on January 19, 2017, 12:04:57 PM
I feel the joker in the pack is the ice in the Weddell embayment? If enough of that is now prone to melt we could go very low this year?
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on January 19, 2017, 02:33:30 PM
The Weddell sea ice is prone to melt much more than usual. It's really warm around antarctica due to dropped albedo. The radiation balance in february in terms of open water or low-concentrated ice is enough to accumulate even more heat.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 20, 2017, 04:43:24 AM
For Jan. 19th JAXA has posted 3,237,501 km2 for SIE around Antarctica.

Down by 75,800 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 20, 2017, 11:34:22 AM
2017, 01, 15,      3642000 sq km
2017, 01, 16,      3493000 sq km
2017, 01, 17       3421000 sq km
2017, 01, 18       3340000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F4287%2Fantar17_18_bgy1.PNG&hash=d49a02c39a3e53b54300fccb169f78d1)



Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 21, 2017, 05:25:11 AM
For Jan. 20th JAXA has posted 3,162,585 km2.

Down by 74,916 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 21, 2017, 05:52:16 PM

2017, 01, 18       3340000 sq km
2017, 01, 19       3246000 sq km
2017, 01, 20       3162000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F1016%2Fantar17_20_kgp5.PNG&hash=6edfeb126b46998cc737c70890107840)

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 22, 2017, 07:07:22 AM
For Jan. 21st JAXA has posted 3,062,611 km2 for SIE around Antarctica.

Down by 99,974 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 23, 2017, 04:54:46 AM
For Jan. 22nd JAXA has posted 2,981,476 km2 for SIE around Antarctica.

Down by 81,135 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: frankendoodle on January 23, 2017, 06:38:32 AM
Of the 10 choices on the poll for SIE 2017 minimum, 5 of them have already passed and it's only January 22nd!
Title: Re: Sea Ice Extent around Antarctica
Post by: georged on January 23, 2017, 09:53:59 AM
Of the 64 forum votes, 62 were for 2.75m or less, so most people are still in with a chance.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 23, 2017, 01:32:27 PM
Also worth noting that there's still a fair amount of extent to lose in/near the Ross sea, which was previously flagged as vulnerable. I think the chances of a record low are looking very strong now; it's really more a question of how much of a record.

EDIT: Does anyone have a link to comparative sea surface temperature / other melting condition data for the southern ocean to better inform our guesswork here?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 23, 2017, 05:22:38 PM
There is a hot spot just off Weddell Sea that may have an influence.
2nd image is a forecast for sea ice thickness for Feb. 1st, but gives an idea of extent also.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on January 23, 2017, 05:36:38 PM
Also worth noting that there's still a fair amount of extent to lose in/near the Ross sea, which was previously flagged as vulnerable. I think the chances of a record low are looking very strong now; it's really more a question of how much of a record.

Warm SST anomaly CONTINUES to intensify in southern Pacific....
Title: Re: Sea Ice Extent around Antarctica
Post by: dingojoe on January 23, 2017, 05:46:38 PM
My lazy layman's best guess (I don't try to crunch data, I just click on alot of EOSDIS) is that the difference between low and a record low depends on what happens with the stretch of ice running from the Bellinghausen Sea to the Thwaites glacier.  Generally speaking the ice is mobile and has been pushed out off of the coast.  The remaining areas of fast ice are relatively exposed (don't have loose ice against them).  These are conducive to melting.  Conversely, some of the ice is thicker than other areas and thus not conducive to melting out.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 24, 2017, 09:47:06 AM
For Jan. 23rd JAXA has posted 2,924,396 km2 for SIE around Antarctica.

Down by 57,080 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 24, 2017, 05:28:45 PM
According to NSIDC, the SIE aound Antarctica was 2,899 Mn km2 for Jan 23. Down by 128K.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 24, 2017, 11:57:59 PM

2017, 01, 20       3162000 sq km
2017, 01, 21       3127000 sq km
2017, 01, 22       3027000 sq km
2017, 01, 23       2899000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F9065%2Fantar17_22_opz3.PNG&hash=a1d62bd2a2428a74764ae26c72a3a2e7)



Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 25, 2017, 04:30:45 AM
For Jan. 24th JAXA has posted 2,840,868 km2 for SIE around Antarctica.

Down by 83,528 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on January 25, 2017, 04:35:43 AM
Relentless....
Title: Re: Sea Ice Extent around Antarctica
Post by: budmantis on January 25, 2017, 06:09:53 AM
At an average daily melt of 50K, the remaining ice will be approaching 1.5M by February 20.
Title: Re: Sea Ice Extent around Antarctica
Post by: frankendoodle on January 25, 2017, 06:27:54 AM
2017 has been melting at a faster rate than 1997 even this late into the melt season. If we were to use 1997 numbers to finish out this melt season, 2017 minimum would be 1.65M km2. As of 1/24 we are 600K km2 ahead of 1997.
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on January 25, 2017, 07:34:21 AM
Can anyone post images or an animation of:
* The current map of the ice.
* The ice map at the same date in 1997.
* The ice map during min in 1997.
Alternatively, extent numbers for the various Antarctic regions on those dates.
This will enable an informed prediction of this year's outcome.
Note: Apologies for not posting the same myself, I am quite illiterate when analyzing Antarctic sea ice.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on January 25, 2017, 09:26:33 AM

Alternatively, extent numbers for the various Antarctic regions on those dates.


I assume that you are aware of :

(NSIDC NT 25km sea ice concentration)
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-ant-nt-area-overview.png
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-ant-nt-extent-overview.png
(Uni Hamburg ASI 3.125km sea ice concentration)
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/uh-amsr2-ant-area-overview.png
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/uh-amsr2-ant-extent-overview.png

Data to be found:

NSIDC:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_final_detail.txt.gz
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_nrt_detail.txt
UH:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/uh_am2_ant.txt

Today's summary:
Regional Antarctic Sea Ice Extent and Area calculated from Uni Hamburg ASI AMSR2 concentration data
Date: 2017-01-24 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
               454.7    +0.3               1171.7   -22.1
                Indian Ocean           West Pacific Ocean
               240.8    +3.9                553.4    +3.3
                    Ross Sea                        Total
               226.2   -38.9               2646.8   -53.6

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
               332.9    -0.5               1062.9   -24.1
                Indian Ocean           West Pacific Ocean
               203.7    +0.5                498.0    -0.8
                    Ross Sea                        Total
               170.6   -14.0               2268.1   -39.0


to be found here: https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/uh_am2_ant_summary.txt

Attaching today's UH graphs.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 25, 2017, 10:28:19 AM
Imho, we're nearing bottom for the year now. Not much left to lose in the Ross sea, and the other regions (a) are only falling slowly and (b) only have relatively secure fast ice remaining. I certainly don't expect that extent will fall below 2 million.
Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on January 25, 2017, 10:31:15 AM
Imho, we're nearing bottom for the year now. Not much left to lose in the Ross sea, and the other regions (a) are only falling slowly and (b) only have relatively secure fast ice remaining. I certainly don't expect that extent will fall below 2 million.
It seems to be the case....
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on January 25, 2017, 01:50:20 PM
"To predict the behavior of ordinary people in advance, you only have to assume that they will always try to escape a disagreeable situation with the smallest possible expenditure of intelligence."

not only true, many would wonder how much of all our current dilemmas are based on that fact
sorry for OT but could not resist, such wisdom can get me drawn away and flying high at times LOL
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 25, 2017, 05:27:01 PM
Comparing the previous minimum with the current SIE (NSIDC numbers) reveals that to reach the 1997 minimum at 2,29 Mn km2 (5-day average) we need to lose another 721K. Not impossible but not an easy task either given that most of the "easy" ice is gone now and most of the remaining one is fairly thick. However, there is one region that I believe will determine the final outcome.

The sea ice in the Somov Sea east of Ross Sea seems to be fairly thin according to Copernicus and should take a decent damage until the beginning of February. The tricky thing is that the model have foreseen this scenario for a while now but the sea ice there have so far been very stubbornish and resistant and also seems to lack melting momentum. If significant melting is to occurr then I think we might reach a new record low minimum. If not, we should clearly be among the five lowest minimums by the middle of February.
Title: Re: Sea Ice Extent around Antarctica
Post by: charles_oil on January 25, 2017, 06:00:05 PM
...and yet the Polar star experienced more / thicker ice than usual:

http://gcaptain.com/ship-photos-u-s-icebreaker-polar-star-reaches-mcmurdo-station-antarctica/ (http://gcaptain.com/ship-photos-u-s-icebreaker-polar-star-reaches-mcmurdo-station-antarctica/)

Quote...
The Coast Guard says that in previous years Polar Star typically worked through approximately 12 to 13 miles of ice to reach McMurdo Station. This year, however, there was more than 60 miles of ice to break with thickness ranging from two feet to more than 10 feet.

“We experienced a significantly larger ice field this year compared to the last several years,” said Capt. Michael Davanzo, commanding officer of the Polar Star. “In several areas, the ice was under considerable pressure and covered with several inches of snow, slowing our progress. Despite these challenges, the crew worked around the clock to prepare the resupply channel before the arrival of the first ship.”

end quote

Looking in NSIDC Chartic this seems odd as it shows next to no ice in the area

Photo caption: The Coast Guard Cutter Polar Star (WAGB-10) and crew create a navigable channel through the frozen Ross Sea off of Antarctica, Jan. 16, 2017. U.S. Coast Guard Photo
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 26, 2017, 04:32:04 AM
For Jan. 25th JAXA has posted 2,761,228 km2 for SIE around Antarctica.

Down by 79,640 km2.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: CalamityCountdown on January 26, 2017, 04:53:35 AM
Seems to be an interesting debate developing re the 2017 low for SIE. Those that are using trend lines from past years as a basis for their estimates (frankendoodle and budmantis) tend to be predicting a new low. Those that are taking a granular view based on a sea by sea review (Lord M Vader and Paddy) seem much more skeptical about a new record low being set. 
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 26, 2017, 05:29:09 AM
...and yet the Polar star experienced more / thicker ice than usual:

...

This is a little odd, but I may be able to square the circle to a degree. The article never said the ice was thicker than normal, only that it was between 2 and 10ft in thickness (0.6 to 3 metres). As maps from the time show (http://forum.arctic-sea-ice.net/index.php/topic,1759.msg99392.html#msg99392 (http://forum.arctic-sea-ice.net/index.php/topic,1759.msg99392.html#msg99392)), there was a wide area of ice a considerable distance offshore in the Ross sea (looking a bit like a rocking horse in the images in the linked post). It's this very area which has since been vanishing from the map, being low thickness and not fast to shore.

It's possible most of the ice met by this icebreaker may have been towards the 2 foot end of the range - it doesn't look particularly thick in the linked images.

Still though... Odd.

@CalamityCountdown,

I actually think a new record low could happen, just not one below 2 million. But I am expecting the daily drops to reduce quite a lot now the Ross and Amundsen seas have basically melted out.
Title: Re: Sea Ice Extent around Antarctica
Post by: Herfried on January 26, 2017, 06:41:29 AM
As a long time lurker... first post. Think I may help here: I googled the position of the ststion. It lays at the very southeast tip of the ice shelf, and that's the very position of the only remaining considerable coastal fast ice blob of the Ross region (now also shrinking)
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on January 26, 2017, 08:22:46 AM
There is some weak ice in the Weddel sea and the melting momentum could continue until the late Februrary. Also Casey-Dumont and Neumayer still melt. As of higher SSTs more warm air could be advected to those areas. I still think the new record low SIE will occur, it'll be about 2000 mln sq km
Title: Re: Sea Ice Extent around Antarctica
Post by: budmantis on January 26, 2017, 09:13:06 AM
"To predict the behavior of ordinary people in advance, you only have to assume that they will always try to escape a disagreeable situation with the smallest possible expenditure of intelligence."

not only true, many would wonder how much of all our current dilemmas are based on that fact
sorry for OT but could not resist, such wisdom can get me drawn away and flying high at times LOL

Thanks Magnamentis! I was thinking of changing my signature line, but after your feedback, I think I'll keep it. Apologies to thread for off-topic discussion.
Title: Re: Sea Ice Extent around Antarctica
Post by: budmantis on January 26, 2017, 09:33:58 AM
Seems to be an interesting debate developing re the 2017 low for SIE. Those that are using trend lines from past years as a basis for their estimates (frankendoodle and budmantis) tend to be predicting a new low. Those that are taking a granular view based on a sea by sea review (Lord M Vader and Paddy) seem much more skeptical about a new record low being set.

Hello C.C.: I don't know much about the Antarctic and have little observational knowledge. As a result, I have little choice but to use trend lines. As previously stated, it looks like a minimum of 1.5m is certainly possible, but as to the final number, I'll leave that to those who know more about the subject.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 26, 2017, 10:34:29 AM
I'm no expert either, but I'm sticking to my prediction of a slowdown in the melt.  If I was to predict hard figures, I'd guess that JAXA extent will bottom out at about 2.3 million square km (+/- 0.2 million). But it really all depends on what happens in the Weddell [edit] and Belingshausen now.
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on January 26, 2017, 12:33:29 PM
If you check out the MODIS image of Ross Island for the 18th you can see the scar in the fast ice that the ice breaker made.

I too found it a bit odd that they had such a torrid time this year so checked the images and , Yes!, Ross sea was near ice free but the base is on the landward side of Ross Island and the 'bay' to access it is frozen solid.

From the images from the 19th the fast ice began to collapse. The report talks about ice under pressure so I wonder if there activities destabilised the ice ( broke it and so reduced the stresses?) on their trip? I bet they wish they's waited a couple of days though!
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on January 26, 2017, 01:45:38 PM
Imho, we're nearing bottom for the year now. Not much left to lose in the Ross sea, and the other regions (a) are only falling slowly and (b) only have relatively secure fast ice remaining. I certainly don't expect that extent will fall below 2 million.

i hold the bet while anything between 1.95 and 2.05 is arbitrary, still we fall continuously an are only 8 days away a the current rate which i, like you don't expect to continue for that period but then another 3 or 4 days above -60k per day and we get so close that we gonna make it for almost sure.

game on LOL
Title: Re: Sea Ice Extent around Antarctica
Post by: charles_oil on January 26, 2017, 02:02:06 PM
Thanks Paddy for comments. 

It was my surprise at the 60 km vs 12/13 km normally that struck me.

I think its actually a case of scale.  See map below - a thin sliver along the coast, or a blob (as NSIDC shows) around Erebus may actually be quite large,

I suspect they would have avoided the "rocking horse" which anyway shows as typically < 50%, so not very solid.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 26, 2017, 04:23:54 PM
2017, 01, 23       2899000 sq km
2017, 01, 24       2838000 sq km
2017, 01, 25       2726000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F6085%2Fantar17_24_obx5.PNG&hash=a373f4f13f6bf1c27fa6e124d5d6c1db)



By the way, Mc Murdo now:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F1409%2FMobileWebCam00069_can4.jpg&hash=a5ba3cf3ad8cf4680ff0cbf907bd83cd)

https://www.usap.gov/videoclipsandmaps/mcmWebCam.cfm (https://www.usap.gov/videoclipsandmaps/mcmWebCam.cfm)

Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on January 26, 2017, 05:45:21 PM
2017, 01, 23       2899000 sq km
2017, 01, 24       2838000 sq km
2017, 01, 25       2726000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F6085%2Fantar17_24_obx5.PNG&hash=a373f4f13f6bf1c27fa6e124d5d6c1db)



By the way, Mc Murdo now:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F1409%2FMobileWebCam00069_can4.jpg&hash=a5ba3cf3ad8cf4680ff0cbf907bd83cd)

https://www.usap.gov/videoclipsandmaps/mcmWebCam.cfm (https://www.usap.gov/videoclipsandmaps/mcmWebCam.cfm)

Where is the damn change in curvature
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 26, 2017, 05:52:12 PM
It's coming soon. As you'll see from the regional breakdown, the most rapid drop in ice has been in the Ross sea, and there's almost nothing left to melt there now.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 26, 2017, 06:41:46 PM
As I have pointed out, the Somov Sea will determine the final outcome of this melting season. Another area that will determine the outcome is East Antarctica where the the extent numbers have been fairly normal.

For today, NSIDC reports a SIE of 2,726 Mn km2. This means that we "only" need to lose  less than 500K to reach the single lowest daily minimum value from 1997 at 2,264 Mn km2.

CC_Reanalyzer shows that the next 5 days will be warmer than normal in the area of Somov Sea and Weddell Sea. This should do at least some damage to the ice in Somov Sea.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on January 26, 2017, 08:09:27 PM
Another area that will determine the outcome is East Antarctica where the the extent numbers have been fairly normal.
This area tracks as usual,but normally it lose about one third of the remaining extent by the annual minimum.
As you can see in the image, much of heat have been accumulated around Antarctica and the melting momentum in February could be longer and stronger.
(https://pp.vk.me/c637924/v637924983/3255a/OvKof4cQg4w.jpg)
Title: Re: Sea Ice Extent around Antarctica
Post by: dingojoe on January 26, 2017, 11:54:06 PM
Three NASA Worldviews of an East Antarctic area off of Enderby Land, which we really haven't discussed:


Jan 4th--Sea Ice melt is lagging previous year.  Large area of loose ice on top of a substantial and long bank of fast ice.  However, note the polynya in the two bays at the right of the shot and in the large bay at the center (Lutzow-Holm Bay).  These don't seem to usual occurrences.

http://go.nasa.gov/2k6J4tm (http://go.nasa.gov/2k6J4tm)

Jan 22nd--A multi-day storm has pushed off much of the loose ice counterclockwise (west) and away from the bank of fast ice.  However, some loose ice has been pushed against the fast ice and has actually increased the area of fast ice.  Extent is lower than on the 4th, but not necessarily conducive to further melting.  Note that the twin bays at the right have experienced considerable fracturing and in fact are now more advanced than the previous year, probably thanks to the polynyas.  Also, note that the polynya in Lutzow-Holm has continued to grow.  Despite the break down of the twin bays, overall melt continues to lag the previous year as the fast ice remains much more substantial.

http://go.nasa.gov/2k6DJ5c (http://go.nasa.gov/2k6DJ5c)

Jan 26th--Winds have totally reversed and are now pushing ice off of the coast.  Not only has the newly fastened ice broken off, but large chunks of previously fast ice have broken or eroded.  While the extent may actually have grown in the region slightly, the potential for melt is now greater.  While the polynya in Lutzow-Holm is obscured by clouds, the breakdown of the twin bays continues and if you zoom in you can note a substantial calving of whatever glacier occupies the west bay.

http://go.nasa.gov/2k6MBbb (http://go.nasa.gov/2k6MBbb)

Melt and breakup of the fast ice still lags last year but the polynya in Lutzow-Holm  seems to be a potential x-factor.  If it continues to erode the fast ice from the back, while the front side continues to erode, it could be repeat of what happened with the twin bays and breakup/melt of the region could actually exceed last year.  As always weather and winds will matter.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 27, 2017, 04:37:53 AM
For Jan. 26th JAXA has posted 2,706,165 km2 for SIE around Antarctica.

Down by 55,063 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: dingojoe on January 27, 2017, 06:24:30 AM
Imho, we're nearing bottom for the year now. Not much left to lose in the Ross sea, and the other regions (a) are only falling slowly and (b) only have relatively secure fast ice remaining. I certainly don't expect that extent will fall below 2 million.

Besides the fast ice off of Enderby, areas of fast ice that are currently breaking down include the stretch between the Ross and Amudsen Sea, McMurdo Bay the Ronne entrance in the Bellinghausen, probably Marguerite Bay in the Bellinghausen (cloud cover) and several small areas along the Coronation.  The stretch of fast ice from the Somov to Davis has been stable with minor erosion.  Of course, just because fast ice breaks up, doesn't mean it will melt out.

The stretch between tho Ross and Amudsen is the most surprising to me as it was pretty low to begin with.
Title: Re: Sea Ice Extent around Antarctica
Post by: budmantis on January 27, 2017, 07:07:55 AM
There is some weak ice in the Weddel sea and the melting momentum could continue until the late Februrary. Also Casey-Dumont and Neumayer still melt. As of higher SSTs more warm air could be advected to those areas. I still think the new record low SIE will occur, it'll be about 2000 mln sq km

I was wondering how susceptible the ice is in the Weddell Sea. Most members think the daily melt numbers will drop as we near the end of the melt season and that certainly could be the case. I thought what Pavel and Dingojoe said in their most recent posts was informative. How much more melt can be expected from that area, which by the way has the largest percentage of remaining ice.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 27, 2017, 07:24:35 AM
Most of the weddell Sea ice is not very thick. I don't think warm air will melt much. Insolation, is probably about to be on the way out. There is a decent size area of warm water nearby, and maybe if the right storm came along and stirred the water up, anything's possible.
Title: Re: Sea Ice Extent around Antarctica
Post by: bairgon on January 27, 2017, 07:28:41 AM
note the polynya in the two bays at the right of the shot and in the large bay at the center (Lutzow-Holm Bay).  These don't seem to usual occurrences.

Red posted about that in the Meltwater thread a little while back:

There has been what looks like upwelling to the right against the land mass growing bigger since November with what appears to be under cutting by current all the way to open ocean.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on January 27, 2017, 07:45:01 PM
Only a very small drop today, down 24K. The 5-day average OTOH dropped more sigificantly (84K) and is now down to 2,839 Mn km2. "Only" 549K more until record low minimum... But OTOH there is not much ice left to melt out.
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on January 27, 2017, 11:43:17 PM
So I've done some number crunching using the NSIDC links Wipneus was kind to provide (I should have had them already), in order to arrive at some better extrapolation of Antarctic SIE at the minimum, based on regional historical data. I am using NSIDC data for Jan 26 as current date.
Regions: bham: Bellingshausen&Amundsen Seas, wedd: Weddel Sea, indo: Indian Ocean, wpac: West Pacific Ocean, ross: Ross Sea

On current date 1997 had a total extent of 3279k, declining to 2264k at minimum on Feb 27. Regional minima occurred within several days of each other, notably wedd started growing about a week before the general minimum. Had all minima improbably occurred on the same day, the total minimum would have been 2125k.
Currently, for Jan 26, 2017 has a total extent of 2702k, or about 576k less than 1997. Extrapolating the total naively using the 1997 decline to minimum would give 1688k for this year.

Looking at each region separately:
bham: now 504k, was 462k on 1997 same date. Fell to 182k at 1997 minimum, declining 280k
wedd: now 1149k, was 1299k on 1997 same date. Fell to 1184k at 1997 minimum, declining 115k
indo: now 277k, was 287k on 1997 same date. Fell to 124k at 1997 minimum, declining 163k
wpac: now 641k, was 569k on 1997 same date. Fell to 426k at 1997 minimum, declining 144k
ross: now 132k, was 661k on 1997 same date. Fell to 348k at 1997 minimum, declining 313k
 
The real shocker is ross, which by itself explains the whole difference between the years and is totally unprecedented. Previous lowest for the date was 424k.

Using the following guesswork:
bham declines 280k to minimum, same as 1997 though it currently has more ice
wedd declines 120k to minimum, or 220k *
indo declines 163k to minimum, same as 1997
wpac declines 144k to minimum, same as 1997 though it currently has more ice
ross declines 30k to minimum, or 100k **
* wedd – looking at the five lowest years for the current date with 919k to 1,130k, three declined 223k-246k to Feb 27, one declined 126k, and one actually grew by 101k (but declined 120k to that year's minimum which came about much earlier). 1997 also declined 115k. Note: timing of wedd minimum vs. total minimum can make a major difference in the outcome.
** ross – any-date minimum was 124k and we are already at 132k. 1997's 313k decline is impossible. Looking at the ten lowest ross years for this date (424k-712k), averaging their decline to Feb 27 gives us about 200k, still impossible. So it's either almost nothing 30k or almost everything 100k, anyone who can analyze actual ross ice situation is warmly welcome to comment. Can it go to zero?
*** The above can be improved for wedd and ross by checking each year's decline to its own minimum date, instead of using Feb 27 for all. The above can be improved for all regions by looking at other similar years and averaging their declines to minimum instead of just using 1997.

The bottom line gives us the following NSIDC SIE minimum based on regional extrapolation:
Low decline scenario - 737k, down to 1,965k
High decline scenario – 907k, down to 1,795k
Midpoint decline – 822k, down to 1,880k

Following this statistical guesswork, I think <2m has a much higher probability than >2m.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 28, 2017, 05:48:01 AM
For Jan. 27th JAXA has posted 2,627,832 km2 for SIE around Antarctica.

Down by 78,333 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 28, 2017, 10:52:40 AM
 Regional breakdown shows how little is left in the Ross now:

(https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-ant-nt-extent-overview.png)

@Oren,

Interesting and thorough analysis, but summing the different declines to minimum by sea assumes they'll all be at minimum on the same date. And although we'd expect them all to hit minimum around the end of Feb based on previous years, there's also likely to be a fair bit of individual variation, especially with ice in Bellingshausen and Weddell extending further north than the others this year, so likely switching from melt to freeze a few days later.
Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on January 28, 2017, 03:04:40 PM
Oren can you repeat that analysis excluding Ross ? That ice is gone and will not play a role for the approach to the minimum from now on.

Got to learn to read the whole message..... Ugh
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on January 28, 2017, 03:31:25 PM
Interesting and thorough analysis, but summing the different declines to minimum by sea assumes they'll all be at minimum on the same date. And although we'd expect them all to hit minimum around the end of Feb based on previous years, there's also likely to be a fair bit of individual variation
Thanks. Just to clarify, I guesstimated the decline of each sea to a general minimum date, not to its own minimum.
Title: Re: Sea Ice Extent around Antarctica
Post by: dingojoe on January 28, 2017, 07:14:47 PM
Judging by recent history, the Ross is one of the first areas to start refreezing, and it  restarts around whatever ice is left from melting season, but if there is no ice left then it'll have to start from scratch which may push back and slow the start of refreeze.

Oren may even be too pessimistic about the minimum in the Ross, outside of the far southern part of Mcmurdo bay and a small area of fast ice between Ross and the Amudsen what ice will be left by mid-Feb?

Great analysis overall by Oren.
Title: Re: Sea Ice Extent around Antarctica
Post by: diablobanquisa on January 28, 2017, 11:10:05 PM

2017, 01, 25       2726000 sq km
2017, 01, 26       2702000 sq km
2017, 01, 27       2651000 sq km


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.meteociel.fr%2Fim%2F2143%2Famtar17_27_icn1.PNG&hash=61aadc05a32417a208e68832299b0d61)

Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 29, 2017, 12:53:51 AM
Thanks. Just to clarify, I guesstimated the decline of each sea to a general minimum date, not to its own minimum.

OK, I may have underestimated the chances of a <2 million minimum based on my own cruder eyeballing of trends by sea. Will be interesting to watch.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 29, 2017, 05:42:25 AM
For Jan. 28th JAXA has posted 2,554,386 km2 for SIE around Antarctica.

Down by 73,446 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: frankendoodle on January 29, 2017, 08:36:40 AM
I applaud everyone's skepticism in regards to SIE bottoming out this season.  But at this point JAXA SIE is 300K from a new record with approx. one month of melt left to go.

Do any of you REALLY THINK we will not hit a record low this year?!

Also, even a severe record low will not be too outside two SD. Antarctica is more about basal continental melt than sea ice. 
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on January 29, 2017, 10:28:29 AM
Do any of you REALLY THINK we will not hit a record low this year?!
The more common question is how low will it go, as shown by the poll held a few weeks ago.
Title: Re: Sea Ice Extent around Antarctica
Post by: Neven on January 29, 2017, 11:10:09 AM
Yes, there is clearly some kind of momentum going on, given the monotonous decline.

This is a great thread. Thanks for all the info, everyone!
Title: Re: Sea Ice Extent around Antarctica
Post by: Herfried on January 29, 2017, 11:41:22 AM
Watchimg the other years show a decline of 3/4 - 1 million of square km from this date to the minimum, rather independent from the overall area. High and low years almost parallel.

Probably the daily melting of ice in all regions is rather kind of a constant. This would bring us way below 2 m of square km
Title: Re: Sea Ice Extent around Antarctica
Post by: lurkalot on January 29, 2017, 12:41:03 PM
Perhaps someone with access to the numbers could start ticking off the rankings - this year's extent must already be below the minima for most years in the satellite record.
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on January 29, 2017, 12:45:10 PM
2.55

390k below previous lowest for day
300k above lowest ever recorded
290k lost in last 4 days

Trends may indicate heading for around 1.8-1.9, but it could still slow down because there is so little ice that is easily melted, or albedo effect putting more heat in surface waters could mean continued decline at steep rate and a late minimum. Worth watch to see which way it goes and why if that can be determined.
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on January 29, 2017, 12:49:40 PM
1997 2.25
2011 2.32
1993 2.37
2006 2.41
1980 2.53
1984 2.53
2017 2.55

so 7th I think
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on January 29, 2017, 01:25:11 PM
For Jan. 28th JAXA has posted 2,554,386 km2 for SIE around Antarctica.

Down by 73,446 km2.
this is getting insane
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on January 29, 2017, 01:47:34 PM
What is remarkable to me about this year's melting season is persistence. At the beginning of September a load of ice disappeared and the melt stayed at record lows month after month. Where were the wobbles?

But my question is : Given four months of record insolation, what has been the effect on SSTs in the region, and are there any models on possible delays to /reductions in refreezing this Austral winter ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on January 29, 2017, 02:23:50 PM
The melting momentum is strong both in Atlantic and Pacific sides. There's enough of weak ice to melt out just in upcoming days. The wind patterns in the Weddel sea compact the ice pack and import additional heat. I don't expect significant slowdown in dropping SIE numbers at least in several days
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on January 29, 2017, 02:29:35 PM
NSIDC extent sorted:

1997-02-27  2.264152
1993-02-19  2.280783
2011-02-22  2.318847
1984-02-27  2.381731
2006-02-20  2.486597
1992-02-23  2.492393
1980-02-25  2.516067
1991-02-27  2.553553
2016-02-17  2.577755
2017-01-28  2.581008

Overtaking today 2000, 1996, 1985 and 1988's min's, now tenth position.

NSIDC area's position is much further down, not even in the top half at position 26:

1993-02-26  1.248163
1984-02-27  1.509585
1996-02-25  1.535481
2000-02-18  1.561033
2006-03-04  1.565059
1999-02-26  1.577058
1981-03-03  1.588790
1997-02-19  1.589288
1985-02-19  1.635733
1992-02-23  1.641926
1980-02-27  1.646186
2002-02-20  1.649281
1998-02-26  1.650298
2011-02-26  1.677629
1988-02-24  1.691611
1982-02-17  1.713860
2016-02-17  1.729589
1983-02-25  1.738279
1986-02-27  1.763319
1987-02-24  1.781372
2009-02-22  1.794061
1991-02-25  1.797485
2005-02-25  1.798750
2007-02-19  1.821313
1989-02-21  1.841981
2017-01-28  1.923221

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 29, 2017, 02:57:28 PM
A  954 hpa LP system is forecast to set up by late on the 31st just off Weddell Sea in an area of warmer water. It will cause waves in the 4+ m range. Some of the sea ice there near the edge, not being very thick, will either be melted out or weakened enough to melt before the season's end.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: lurkalot on January 29, 2017, 04:11:15 PM
Thank you Crandles and Wipneus.
Title: Re: Sea Ice Extent around Antarctica
Post by: logicmanPatrick on January 29, 2017, 04:22:19 PM
Some info about sea ice, esp. in the Ross sea area.

1st image shows sea ice in 1974 - source NSF (https://www.nsf.gov/pubs/1997/antpanel/5signif.htm)

2nd image: map shows actual edge of the ice shelf about 1963 - source - glacier explorer (http://glacierexplorer.com/2014/01/cracks-last-ocean-ross-sea-antarctica/)

3rd image shows today's sea ice.  Enhanced and cropped from antarctic mosaic section (https://lance.modaps.eosdis.nasa.gov/imagery/subsets/?subset=Antarctica_r02c04.2017028.aqua.250m)

Note where sea ice retreated in about 1963 to the calving fronts of the glaciers.
Title: Re: Sea Ice Extent around Antarctica
Post by: Red on January 29, 2017, 06:06:56 PM
The Leutzow-Holm Bay has melted out three times in the past as I understand it. In the mid sixties, 1980 and 1988. During these retreats of the fast ice in the bay the Shirase Glaciers toe collasped. I'm watching this progress and wondering if this will be deja vu all over again. The toe looks well shattered so a loss of the fast ice will give it loads of room to stretch and relax. On the left side of the open water in the pollyanna there is a large piece of fast ice starting to split off running almost up to the toe. This piece of ice is about 15x45kms which, I think, would give the Shirase some room to start a maneuver? Would the afore mentioned years have any similarities to the SIE this year?
Title: Re: Sea Ice Extent around Antarctica
Post by: dingojoe on January 29, 2017, 07:02:40 PM
The Leutzow-Holm Bay has melted out three times in the past as I understand it. In the mid sixties, 1980 and 1988. During these retreats of the fast ice in the bay the Shirase Glaciers toe collasped. I'm watching this progress and wondering if this will be deja vu all over again. The toe looks well shattered so a loss of the fast ice will give it loads of room to stretch and relax. On the left side of the open water in the pollyanna there is a large piece of fast ice starting to split off running almost up to the toe. This piece of ice is about 15x45kms which, I think, would give the Shirase some room to start a maneuver? Would the afore mentioned years have any similarities to the SIE this year?

A relevant shot from Worldview

http://go.nasa.gov/2kC8vAJ (http://go.nasa.gov/2kC8vAJ)

Besides the crack Red mentions, there is a faint secondary crack that goes northward towards the outer fast ice edge before curving across to the oddly colored channel Red referenced in the Melt Ice thread.
Title: Re: Sea Ice Extent around Antarctica
Post by: Red on January 29, 2017, 08:20:13 PM
The Leutzow-Holm Bay has melted out three times in the past as I understand it. In the mid sixties, 1980 and 1988. During these retreats of the fast ice in the bay the Shirase Glaciers toe collasped. I'm watching this progress and wondering if this will be deja vu all over again. The toe looks well shattered so a loss of the fast ice will give it loads of room to stretch and relax. On the left side of the open water in the pollyanna there is a large piece of fast ice starting to split off running almost up to the toe. This piece of ice is about 15x45kms which, I think, would give the Shirase some room to start a maneuver? Would the afore mentioned years have any similarities to the SIE this year?

A relevant shot from Worldview

http://go.nasa.gov/2kC8vAJ (http://go.nasa.gov/2kC8vAJ)

Besides the crack Red mentions, there is a faint secondary crack that goes northward towards the outer fast ice edge before curving across to the oddly colored channel Red referenced in the Melt Ice thread.

Polar view on the 26th.
http://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SSH_20170126T175526_8079_S_1.final.jpg (http://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SSH_20170126T175526_8079_S_1.final.jpg)
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on January 29, 2017, 09:15:47 PM
The Leutzow-Holm Bay has melted out three times in the past as I understand it. In the mid sixties, 1980 and 1988. During these retreats of the fast ice in the bay the Shirase Glaciers toe collasped. I'm watching this progress and wondering if this will be deja vu all over again. The toe looks well shattered so a loss of the fast ice will give it loads of room to stretch and relax. On the left side of the open water in the pollyanna there is a large piece of fast ice starting to split off running almost up to the toe. This piece of ice is about 15x45kms which, I think, would give the Shirase some room to start a maneuver? Would the afore mentioned years have any similarities to the SIE this year?

A relevant shot from Worldview

http://go.nasa.gov/2kC8vAJ (http://go.nasa.gov/2kC8vAJ)

Besides the crack Red mentions, there is a faint secondary crack that goes northward towards the outer fast ice edge before curving across to the oddly colored channel Red referenced in the Melt Ice thread.

Polar view on the 26th.
http://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SSH_20170126T175526_8079_S_1.final.jpg (http://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SSH_20170126T175526_8079_S_1.final.jpg)

those ar pics for those who claimed already days ago that there is no more ice to melt LOL

one has to do the math a bit more thoroughly, even that small stripe of ice (landfast ice for example) is many thousands of kilometers in length and that calculated times a few hundred meters or a few kilometers in width makes quite quickly a few hundred thousand km2
Title: Re: Sea Ice Extent around Antarctica
Post by: Red on January 29, 2017, 09:49:35 PM
The Leutzow-Holm Bay has melted out three times in the past as I understand it. In the mid sixties, 1980 and 1988. During these retreats of the fast ice in the bay the Shirase Glaciers toe collasped. I'm watching this progress and wondering if this will be deja vu all over again. The toe looks well shattered so a loss of the fast ice will give it loads of room to stretch and relax. On the left side of the open water in the pollyanna there is a large piece of fast ice starting to split off running almost up to the toe. This piece of ice is about 15x45kms which, I think, would give the Shirase some room to start a maneuver? Would the afore mentioned years have any similarities to the SIE this year?

A relevant shot from Worldview

http://go.nasa.gov/2kC8vAJ (http://go.nasa.gov/2kC8vAJ)

Besides the crack Red mentions, there is a faint secondary crack that goes northward towards the outer fast ice edge before curving across to the oddly colored channel Red referenced in the Melt Ice thread.

Polar view on the 26th.
http://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SSH_20170126T175526_8079_S_1.final.jpg (http://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SSH_20170126T175526_8079_S_1.final.jpg)

those ar pics for those who claimed already days ago that there is no more ice to melt LOL

one has to do the math a bit more thoroughly, even that small stripe of ice (landfast ice for example) is many thousands of kilometers in length and that calculated times a few hundred meters or a few kilometers in width makes quite quickly a few hundred thousand km2
Magna that entire coast of Enderby Land melted out last year from Cape Ann to just east of Leutzow-Holm Bay and the shape it's in this year I would expect it to take the bay with it at present rate. I have no idea about area but it's a wee bit. The whole damn continent is waking up this year. Just nuts.
Title: Re: Sea Ice Extent around Antarctica
Post by: FredBear on January 29, 2017, 11:21:30 PM
On arctic io you can see bits breaking up all round - some like McMurdo have more ice this year but are now breaking up.
The Weddell sea is the area with the most ice adrift but is there too much to allow significant warming? The ice does retreat from the east side, leaving the Brunt Ice Shelf area relatively free, particularly in earlier years. There is a large piece of ice west of Brunt which looks the same as in 2013!
I wonder if the sea ice in the Amundsen Sea eastwards is broken up enough to follow the example of Ross's sea ice and disappear?
I notice the "small" piece of the PIG which broke off the other day is moving out into clear water.
Lots of water to absorb solar energy, the question is whether there will be enough heat to make much difference to the continent's fringes?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 29, 2017, 11:50:05 PM
The Low that is getting ready to set up over warmer water near  the Weddell Sea starts out with a twin directly over the ice. The two systems will convey circulation of air between them. After a couple days, one Low will be left over the Sea. One area in particular near the shore will be most affected by waves, until about the 3rd of Feb. when waves will set further offshore and attack another area of ice. Winds will not be terribly strong from these, but will persist over a long time. The Peninsula which usually protects the sea ice, will be on the wrong side of this all. I am not even trying to begin to guess the outcome for the sea ice, but noting the possibility that it could be bad.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 30, 2017, 05:32:36 AM
For Jan. 29th JAXA has posted 2,504,147 km2 for SIE around Antarctica.

Down by 50,239 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on January 30, 2017, 02:35:37 PM
NSIDC extent drops -69k, area -46k.

Extent overtakes 1980, 1991 and 2016, now at pos #7
Area stays at #26

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2006-02-20 2.486597
6 1992-02-23 2.492393
7 2017-01-29 2.512386
8 1980-02-25 2.516067
9 1991-02-27 2.553553
10 2016-02-17 2.577755
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 1986-02-27 1.763319
20 1987-02-24 1.781372
21 2009-02-22 1.794061
22 1991-02-25 1.797485
23 2005-02-25 1.798750
24 2007-02-19 1.821313
25 1989-02-21 1.841981
26 2017-01-29 1.876840
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 30, 2017, 04:57:36 PM
Tomorrow.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: lurkalot on January 31, 2017, 01:19:55 AM
Those figures from Wipneus are intriguing. If extent falls another 10% it will be a new satellite-era low and most contributors seem to expect that will happen. Yet apply a 10% fall to the current area figure and this year would only be in around 15th spot. Another oddity is the 1993 area which is hugely lower than any other year. Any suggestions as to what is/has been going on?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on January 31, 2017, 04:35:33 AM
For Jan. 30th JAXA has posted 2,468,573 km2 for SIE around Antarctica.

Down by 35,574 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 31, 2017, 09:03:06 AM
Current concentration map shows lots of low concentration ice in the Belliingshausen sea, small amounts elsewhere:

(https://seaice.uni-bremen.de/data/amsr2/today/Antarctic_AMSR2_nic.png)
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on January 31, 2017, 09:35:08 AM
Those figures from Wipneus are intriguing.

Yes, area at rank 26 out of 39 does not seem to be particularly low. It indicates relative high compactness (area/extent, no graph yet) of the remaining ice pack. 

I left out the higher values minimums, that may be interesting too, here they are:

26 2017-01-29 1.876840
27 1979-02-20 1.926174
28 2012-02-23 1.931870
29 2010-02-20 1.933016
30 1995-02-17 2.002174
31 1990-02-22 2.026988
32 1994-02-18 2.098845
33 2004-02-22 2.154999
34 2008-02-20 2.203494
35 2001-02-19 2.286595
36 2013-02-20 2.389945
37 2015-02-14 2.414870
38 2014-02-19 2.423633
39 2003-02-27 2.448344


So we area about midway between the highest (2.448, 2003) and the lowest (1.248, 1993).
Title: Re: Sea Ice Extent around Antarctica
Post by: Tealight on January 31, 2017, 10:51:38 AM
/Those figures from Wipneus are intriguing. If extent falls another 10% it will be a new satellite-era low and most contributors seem to expect that will happen. Yet apply a 10% fall to the current area figure and this year would only be in around 15th spot. Another oddity is the 1993 area which is hugely lower than any other year. Any suggestions as to what is/has been going on?

I think in 1993 strong foehn winds moved over the Antarctic Peninsula and reduced the Weddel Sea to rubble. The whole east coast of the Peninsula was ice free. Maybe this was a preconditioning for the Larsen A breakup.

On my website the AWP daily animations show the whole 1992/93 melting season.
https://sites.google.com/site/cryospherecomputing/warming-potential/Albedo-Warming-Overview/1992-3

Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on January 31, 2017, 02:01:49 PM
NSIDC extent : 2.496M down  -15.9k. 2017 Ranking for the lowest minimum unchanged at #7
NSIDC area: 1.855M down  -22.2k. 2017 Ranking for the lowest minimum unchanged at #26
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on January 31, 2017, 02:37:21 PM
How do the area figures for this date compare with previous?
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on January 31, 2017, 03:12:35 PM
How do the area figures for this date compare with previous?

Good question, that is the proper comparison of course. Here are the bottom ten for extent and area:

NSIDC extent SH
2007-01-30 3.317009
1988-01-30 3.293921
2016-01-30 3.281563
1985-01-30 3.236064
1984-01-30 3.171942
1997-01-30 3.073323
1993-01-30 3.055230
2011-01-30 3.051893
2006-01-30 2.965328
2017-01-30 2.496448
NSIDC area SH
2002-01-30 2.215836
2016-01-30 2.163698
1981-01-30 2.157176
2000-01-30 2.140510
1985-01-30 2.130137
1984-01-30 2.098387
1997-01-30 2.059385
2006-01-30 2.017084
2017-01-30 1.854593
1993-01-30 1.725503


So we have a first and a second place for extent and area.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on January 31, 2017, 03:27:08 PM
2011-01-30 3.051893
2006-01-30 2.965328
2017-01-30 2.496448

So we're almost 16% below the previous record low NSIDC extent for this date.  16% is a pretty good chunk.

Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on January 31, 2017, 04:04:17 PM
"Any suggestions?"
Maybe 93 opened up avenues for ocean currents to begin acting on basal ice, the melting and spreading of which added to sea ice cover. Perhaps now most of the 'easy' ice has gone slowing basal melt etc. and leading to a new phase in Antarctic melt. On the other hand it's been a strange year all round and next year may be more typical.
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on January 31, 2017, 06:10:34 PM
I'm worried that the change in Pacific drivers to positive, back in 2014, combined with a healing Ozone hole has put us back into 'ice loss' around Antarctica. The trouble with Antarctic ice is when storms disturb the outer ice it can float off and so inflate extent giving a false picture? What is viewed as ice growth is, in fact, ice collapse?

If we see poor growth over the Southern winter ( with the Southern continents suffering cold plunges and Antarctica seeing WAA) then we must begin to consider that Antarctica will now begin a downward trend is Sea ice and an uptick in Shelf calving.
Title: Re: Sea Ice Extent around Antarctica
Post by: FredBear on January 31, 2017, 07:11:46 PM
If bits of Larsen C (and any other icebergs/shelves) just drift off north, they will not make much difference to SIE. They may, however, block circulation in parts of the sea if they get grounded and that may increase SIE.
It is if they collapse like Larsen B that they can prop up extent for years (decades?) by reinforcing the sea ice building during the following winters? (I feel that the Weddell Sea used to have less SIE before 2002?).
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on January 31, 2017, 09:38:16 PM
If bits of Larsen C (and any other icebergs/shelves) just drift off north, they will not make much difference to SIE. They may, however, block circulation in parts of the sea if they get grounded and that may increase SIE.
It is if they collapse like Larsen B that they can prop up extent for years (decades?) by reinforcing the sea ice building during the following winters? (I feel that the Weddell Sea used to have less SIE before 2002?).
Looking at a chart of Weddel Sea extent at the current date over the years, there does did seem to be a general upward trend, but I can't see any specific change point following 2002.
Title: Re: Sea Ice Extent around Antarctica
Post by: DavidR on February 01, 2017, 01:23:01 AM
"Any suggestions?"
Maybe 93 opened up avenues for ocean currents to begin acting on basal ice, the melting and spreading of which added to sea ice cover. Perhaps now most of the 'easy' ice has gone slowing basal melt etc. and leading to a new phase in Antarctic melt. On the other hand it's been a strange year all round and next year may be more typical.
One possibility is that the global cooling that occurred after the Mt Pinatubo eruption reached the Arctic and Antarctic during 1993 causing a significant decline in temperatures and subsequent  increases in Sea Ice. Both the Arctic and the Antactic show a significant decline in temperatures in 1993. Comparison with the effects of an El Nino suggests that the polar temperature shifts have a tendency to trail global temperature shifts by a year or two.

Measured at the 60-80 lattitudes, average annual Antarctic temperatures dropped from -15.3 in 1991 to -16.5 in 1993.  The 1993 minimum would have occurred before the 1993 average dropped. They did not return above -15.3 until 2001. 
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 01, 2017, 05:33:14 AM
For Jan. 31st JAXA has posted 2,449,346 km2 for SIE around Antarctica.

Down by 19,227 km2.

Weddell Sea concentration loss from storm.CLICK IMAGE(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 01, 2017, 03:16:29 PM
SH NSIDC extent drops -8k5, SH NSIDC area drops -14k9.

Small changes, but in the ranking of annual minimums both extent and area did rise one place. Extent now #6, area is #25.

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2006-02-20 2.486597
6 2017-01-31 2.487992
7 1992-02-23 2.492393

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 1986-02-27 1.763319
20 1987-02-24 1.781372
21 2009-02-22 1.794061
22 1991-02-25 1.797485
23 2005-02-25 1.798750
24 2007-02-19 1.821313
25 2017-01-31 1.839665
26 1989-02-21 1.841981


No changes in the daily positions, extent is lowest and area the second lowest for the date.
Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on February 01, 2017, 10:06:54 PM
DavidR Your suggestion makes more sense.
Tigertowns animation is good but more detail shows on the original site, I ran it from the 26th to the 9th at one fps it looks like a big crack shows up on the 3rd then stretches next the northern ice disconnects from the peninsular but again these show best in animation. Is Larsen about to get a push?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D-691308.59375%252C2685229.4921875%252C1014013.671875%252C3925463.8671875%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Dsiconc%26amp%3Btime%3D2017-02-04T12%25253A00%25253A00.000Z%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D0%252C0.99589527%26amp%3BdisplayScaleRange%3D0%252C0.99589527%26amp%3Bopacity%3D1%26amp%3Bbbox%3D-691308.59375%252C2685229.492188%252C1014013.671875%252C3925463.867188%26amp%3BlayerTitle%3Dsea_ice_area_fraction%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32761%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dnull%26amp%3Bunits%3D1%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_south_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_south_pole_no_ocean&hash=d4636cada248493e0ffa01b45bc9006a)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcmems-view.cls.fr%2F%2FViewService%2Fscreenshots%2FcreateScreenshot%3Fdataset%3Dhttp%253A%252F%252Fnrtcmems.mercator-ocean.fr%252Fthredds%252Fwms%252Fglobal-analysis-forecast-phy-001-024%26amp%3BnumColorBands%3D20%26amp%3BlogScale%3Dfalse%26amp%3Bbbox%3D-691308.59375%252C2685229.4921875%252C1014013.671875%252C3925463.8671875%26amp%3Babovemaxcolor%3D0x000000%26amp%3Bbelowmincolor%3D0x000000%26amp%3Bnodatacolor%3Dnull%26amp%3Blayer%3Dsiconc%26amp%3Btime%3D2017-02-08T12%25253A00%25253A00.000Z%26amp%3Bpalette%3Drainbow%26amp%3Bstyle%3Dboxfill%26amp%3BscaleRange%3D0%252C0.99589527%26amp%3BdisplayScaleRange%3D0%252C0.99589527%26amp%3Bopacity%3D1%26amp%3Bbbox%3D-691308.59375%252C2685229.492188%252C1014013.671875%252C3925463.867188%26amp%3BlayerTitle%3Dsea_ice_area_fraction%252Cdaily%2Bmean%2Bfields%2Bfrom%2BGlobal%2BOcean%2BPhysics%2BAnalysis%2Band%2BForecast%2Bupdated%2BDaily%26amp%3Bcrs%3DEPSG%253A32761%26amp%3BmapHeight%3D800%26amp%3BmapWidth%3D1024%26amp%3Bstyle%3Dboxfill%26amp%3BzUnits%3Dnull%26amp%3Bunits%3D1%26amp%3BbaseUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BbaseLayers%3Dcls%253Anoaa_blue_marble_south_pole%26amp%3BoverlayUrl%3Dhttp%253A%252F%252Fgeoserver.myocean.eu%252Fgeoserver%252Fwms%253F%26amp%3BoverlayLayers%3Dcls%253Anoaa_blue_marble_south_pole_no_ocean&hash=0567bbce1117334103f6235d0ce9b7ac)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 02, 2017, 05:25:35 AM
For Feb. 1st JAXA has posted 2,422,393 km2 for SIE around Antarctica.

Down by 26,953 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on February 02, 2017, 02:23:17 PM
IJIS 2.42

170k above record low

lost just 80k in last 3 days (much slower than the approx 70k per day before that)

At that rate it would take until Feb 18 to reach 2 million, but further slowing might be expected as the minimum is approached. So perhaps beginning to look like it will stay above 2 million km2. Of course this is dodgy reasoning, a couple of days of large falls or rises could result in a very different conclusion.

Looks smoother than Arctic but could still change direction and this could have large effect yet.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 02, 2017, 02:38:12 PM
SH NSIDC extent, area lost -13k5, -24k6 today.

In the rankings of the lowest annual minimums, 2017 overtook one year in eacht ranking. Extent is now #5 , area is #24.

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-01 2.474530
6 2006-02-20 2.486597
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 1986-02-27 1.763319
20 1987-02-24 1.781372
21 2009-02-22 1.794061
22 1991-02-25 1.797485
23 2005-02-25 1.798750
24 2017-02-01 1.815087
25 2007-02-19 1.821313


The daily rankings did not change. Extent is still the lowest and area the second lowest for the same day.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 03, 2017, 05:32:33 AM
For Feb. 2nd JAXA has posted 2,390,157 km2 for SIE around Antarctica.

Down by 32,236 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on February 03, 2017, 10:50:19 AM
Only about 3 weeks untll the minimum now, based on previous years.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 03, 2017, 02:12:23 PM
SH NSIDC extent: -46k
SH NSIDC area: -34k

2017 extent minimum is now 5th lowest  (unchanged)
2017 area minimum is now 21st lowest  (was #24)

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-02 2.428219
6 2006-02-20 2.486597
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 1986-02-27 1.763319
20 1987-02-24 1.781372
21 2017-02-02 1.781591
22 2009-02-22 1.794061
23 1991-02-25 1.797485
24 2005-02-25 1.798750


In daily values 2017 extent is lowest, and area second lowest.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on February 03, 2017, 02:19:00 PM
Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-02 2.428219
6 2006-02-20 2.486597
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481

That 1993 Area sure looks like a "tough nut to crack". 
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 03, 2017, 10:32:50 PM
With about 2 weeks until minimum I have identified five minor areas which will be be crucial for the final outcome. See attached figure. Courtesy: University of Bremen.

While the sea ice in the Ross Sea is exceptionally low and Weddell Sea very low it's fascinating to see the sea ice extent in East Antarctica run about normal or even somewhat above normal. To me, it seems like the remaining sea ice in East Antarctica is more or less completely void of melting momentum. The ice in Somov Sea have been very resilient so far and I wonder if it's going to melt any more significantly until refreezing starts.

Finally, the 5-day forecast from CCI_Reanalyzer indicates very warm days ahead for West Antarctica while cooler than normal conditions is foreseen for East Antarctica. See attached figure. Courtesy: CCI_Reanalyzer
Title: Re: Sea Ice Extent around Antarctica
Post by: Neven on February 03, 2017, 11:15:19 PM
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 03, 2017, 11:28:04 PM
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
I'm thinking the Peninsula blocks both water currents and because of elevation, at the very least alters wind patterns. Just a guess.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on February 03, 2017, 11:36:06 PM
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
I'm thinking the Peninsula blocks both water currents and because of elevation, at the very least alters wind patterns. Just a guess.
My layman understanding is the same, plus the wind pattern around Antarctica is clockwise, hence the east side of the peninsula is protected.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on February 04, 2017, 12:12:49 AM
Maybe a stupid question, but why doesn't the sea ice in the Weddell Sea melt out more? Is it because it is more or less enclosed, unlike the rest of the sea ice around Antarctica?
I'm thinking the Peninsula blocks both water currents and because of elevation, at the very least alters wind patterns. Just a guess.
My layman understanding is the same, plus the wind pattern around Antarctica is clockwise, hence the east side of the peninsula is protected.

my 2 cents are that the wind over the peninsula turns into some kind of foehn winds that would make them even slightly warmer ( but not really warm of course )

the main reason might be the assult of the heavy seas on the western side which is missing on the eastern (lee) side. Lee not only as far as the winds are concerned but especially the ocean currents with their wave action and the swells.

so i agree that the eastern side is potected, hence in "Lee" but that the ocean has the greater impact on the western side than the winds have. there must be foehn winds if a wind comes over an elevation and drops down to sea-level (or any lower level) on the other side, that's the case every where in the world where wind currents flow over a mountain ridge, whatever the names are (chenook foehn, mistral, tramontana and the likes.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 04, 2017, 05:30:42 AM
For Feb. 3rd JAXA has posted 2,382,580 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Neven on February 04, 2017, 10:57:22 AM
Thanks for the answers. I guessed as much. If area was so low at the min in 1993, I guess something would have happened there, right? Given that there is so little ice elsewhere. Maybe some extreme katabatic winds - that MM mentions - coming down from those mountains pushing the ice outwards?
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 04, 2017, 01:39:33 PM
Just a lousy 2K drop today to 2,426 Mn km2.... 5-day average down to 2,463 Mn km2. We are still 4th lowest on record.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 04, 2017, 02:37:18 PM
SH NSIDC extent: -1.8k
SH NSIDC area: -12.1k

2017 extent minimum is now 5th lowest  (unchanged)
2017 area minimum is now 20st lowest  (was #21)

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-03 2.426406
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 1986-02-27 1.763319
20 2017-02-03 1.769445
21 1987-02-24 1.781372


In daily values 2017 extent is still lowest, and area still second lowest.
Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on February 04, 2017, 03:16:58 PM
Just to add to Nevens ans. This image shows the amphidromic points around which the tides rotate, clockwise in the SH, so rotating into and within the Weddel sea. There's limited movement at those foci, so I'm guessing any water entering is going to use up it's melting potential on the eastern side, generating fresher water so as it moves out on the western side it's easier to refreeze. Plus you have the stability of the point within the sea inhibiting breakup.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FtO07F%2F13ba9e36ba.png&hash=c537b54b147471ff20d6c00db14d970e)
From http://www.esr.org/documents/padman/robertson_etal_98/robertson_etal_98.pdf (http://www.esr.org/documents/padman/robertson_etal_98/robertson_etal_98.pdf) where there are more images including bathymetry.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 05, 2017, 10:22:52 AM
For Feb. 4th JAXA has posted 2,373,021 km2 for SIE around Antarctica.

Down by 9,559 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 05, 2017, 01:59:17 PM
And for Feb. 4, NSIDC is reporting another lousy 8K drop to 2,418 Mn km2. At least another 10 days are ahead until we reach the date when the earliest minimum occurred (Feb. 15). And time is starting to run out now to make a new record low minimum to occur. The last 6 days have seen a drop of "only" 94K according to NSIDC data.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 05, 2017, 02:24:07 PM
The remaining ice holds bravely:

SH NSIDC extent: -8.0k
SH NSIDC area: -10.5k

Still it means the drop in area means one place lost in the annual minimum ranking. Area is now #19, while extent stays at #5.
Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-04 2.418404
Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2016-02-17 1.729589
18 1983-02-25 1.738279
19 2017-02-04 1.758907
20 1986-02-27 1.763319


In daily values 2017 extent is still lowest, and area still second lowest:
extent SH
2007-02-04 3.101119
1988-02-04 3.080869
1985-02-04 3.036704
2016-02-04 2.963989
1984-02-04 2.962201
1997-02-04 2.825638
2006-02-04 2.784496
2011-02-04 2.769953
1993-02-04 2.761674
2017-02-04 2.418404
area SH
1999-02-04 2.001531
1982-02-04 1.992335
1984-02-04 1.983035
2016-02-04 1.980406
1981-02-04 1.962684
1997-02-04 1.910146
2006-02-04 1.889583
2000-02-04 1.828389
2017-02-04 1.758907
1993-02-04 1.556669


Title: Re: Sea Ice Extent around Antarctica
Post by: oren on February 05, 2017, 03:54:55 PM
And for Feb. 4, NSIDC is reporting another lousy 8K drop to 2,418 Mn km2. At least another 10 days are ahead until we reach the date when the earliest minimum occurred (Feb. 15). And time is starting to run out now to make a new record low minimum to occur. The last 6 days have seen a drop of "only" 94K according to NSIDC data.
Ever since I published my statistical prediction it's been stalling  ::)
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on February 05, 2017, 06:04:36 PM
Just as when I was saying "it's about to start slowing down" the next few days after that saw good large drops. Easy to trip up on predictions.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 06, 2017, 05:46:34 AM
For Feb. 5th JAXA has posted 2,356,536 km2 for SIE around Antarctica.

Down by 16,485 km2.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 06, 2017, 02:06:04 PM
NSIDC area makes a recovery! (0.3k or half a pixel worth of sea ice).

SH NSIDC extent: -20.0k
SH NSIDC area: +0.3k

Neither extent or area makes any change in the rankings today, so same as yesterday.
Title: Re: Sea Ice Extent around Antarctica
Post by: iceman on February 06, 2017, 04:44:49 PM
With about 2 weeks until minimum I have identified five minor areas which will be be crucial for the final outcome. See attached figure. Courtesy: University of Bremen.
   ....

With a stationary low off the coast and a deeper low approaching, it looks like #2 and #3 (and eastwards) will be significant contributors to extent loss between now and the minimum.
    courtesy: ClimateReanalyzer.org
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on February 06, 2017, 07:44:47 PM
I'd agree with the areas 2&3 (Belliingshausen sea) forecast for a drop, especially as there's been a recent rise there that's likely to be dispersal under current conditions.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 07, 2017, 05:55:51 AM
Jaxa dropped only a little today (5th) and landed at 2,353,285 km2.

Since it has leveled off so, I do not intend to post everyday, short of big changes on a given date or accumulated over several days. If someone else feels inclined to post JAXA SIE, fine. If not, I will do so as called for.
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on February 07, 2017, 06:37:10 AM
Nullschool shows that the losses may accelerate again over the coming days, perhaps peaking around the 10th, as the main driver of Antarctic sea ice change is wind patterns:

https://earth.nullschool.net/#2017/02/10/0600Z/wind/surface/level/orthographic=-265.39,-83.88,762
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 07, 2017, 02:02:26 PM
SH NSIDC extent: -12.9k
SH NSIDC area: -31.8k

2017 extent minumum stays at place 5 (but is now only less than 4 k from #4)
Area skips 2 and is now at place 17.

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 1984-02-27 2.381731
5 2017-02-06 2.385412

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2011-02-26 1.677629
15 1988-02-24 1.691611
16 1982-02-17 1.713860
17 2017-02-06 1.727467
18 2016-02-17 1.729589
19 1983-02-25 1.738279



Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on February 07, 2017, 02:04:08 PM
A horse race to the finish line....
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on February 07, 2017, 09:11:34 PM
The melting momentum is strong in the Weddel sea. Wind pushes ice pack outward of the coast and polynya opens along the penisula
(https://pp.vk.me/c639527/v639527983/5e2c/uXHg_secGvk.jpg)
Title: Re: Sea Ice Extent around Antarctica
Post by: iamlsd on February 08, 2017, 01:09:15 PM
Thought I'd have a shot at this:

Jaxa Sea Ice Extent for 7/02/2017 is up a little at 2,355,011 km2.

Hope I'm sourcing this correctly from https://ads.nipr.ac.jp/vishop/#/extent
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 08, 2017, 01:41:45 PM
Oooops! An decent uptick of 43K today to 2,428 Mn km2! And the 5-day average is the same as yesterday, 2,411 Mn km2. And only about a week left before refreezing will be very imminent. Will we end up with a surprising no new record low extent for 2017? What an anticlimax that would be! We are currently ONLY 164K above the 1997 record low minimum!
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 08, 2017, 01:50:15 PM
Oooops! An decent uptick of 43K today to 2,428 Mn km2! And the 5-day average is the same as yesterday, 2,411 Mn km2. And only about a week left before refreezing will be very imminent. Will we end up with a surprising no new record low extent for 2017? What an anticlimax that would be! We are currently ONLY 164K above the 1997 record low minimum!

It is kind of like all the excess energy has shifted to the Arctic again. At least, at the surface.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 08, 2017, 02:18:46 PM
SH NSIDC extent: +42.4k
SH NSIDC area: +7.6k

Annual minimums did not change obviously.
In the daily rankings 2017 area lost one place and is now #3 after 1993 and 2000:

area SH
2016-02-07 1.943511
1996-02-07 1.918787
1985-02-07 1.895955
1999-02-07 1.870074
1981-02-07 1.816876
2006-02-07 1.813437
1997-02-07 1.804732
2017-02-07 1.735088
2000-02-07 1.712887
1993-02-07 1.469682
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on February 08, 2017, 03:30:07 PM
Ice pack is spreading in the Weddell sea, this pattern will continue in several days. Well, really +-100k of extent is not big deal. The more important is how high will be SSTs and what will happen thereby in the freezing season
Title: Re: Sea Ice Extent around Antarctica
Post by: iceman on February 08, 2017, 03:34:39 PM
Has anyone seen graphs or calculations for insolation this Antarctic summer?  Beyond the absolute extent anomaly, the missing ice is mostly at higher latitudes, and locations where ice exceeds the median edge are relatively lower-latitude.  This would have a modest multiplier effect on insolation anomaly, assuming near-normal cloud conditions around the solstice.

Antarctic sea ice extent February 5, 2017
Credit: National Snow and Ice Data Center
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 09, 2017, 05:25:43 AM
For Feb. 8th JAXA has posted 2,321,526 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 09, 2017, 07:39:23 AM
From Bremens pic today, it seems like refreezing has begun at East Antarctica. The end is coming closer and I won't be surprised if we are going to see a record early minimum date this year.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on February 09, 2017, 08:47:10 AM
I'd still predict there may be a little more melting to come this next week, in Belliinghausen anyway, based on the forecast temperatures and fragility of what's there.

5 day temperature anomaly forecast from climatereanalyzer.org:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpamola.um.maine.edu%2Ffcst_frames%2FGFS-025deg%2F5-day%2FGFS-025deg_ANT-LEA_T2_anom_5-day.png&hash=7eac334209405fbc5d368571d518bfa8)

(And the high winds forecast for the same sea from the same source)
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 09, 2017, 02:31:57 PM
SH NSIDC extent: -14.2k
SH NSIDC area: -18.5k

No changes in the annual minimum rankings.

In the daily rankings extent is #1 lowest, area is at #2 (skipped 2000 again).
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on February 09, 2017, 03:17:26 PM
4960,1997,02,19,577584000,2251372

10038,2011,02,22,1019606400,2315254

12212,2017,02,08,1207785600,2321526

ADS/JAXA/IJIS
statistical tie for 2nd lowest year (probably even for lowest?)

70k above record lowest and fall of 34k in last day.   ... so ~3 days to record low..... or 35k in previous 5 days so perhaps ~10 days to record low... or maybe minimum is past before record is reached....

Title: Re: Sea Ice Extent around Antarctica
Post by: steve s on February 09, 2017, 07:37:42 PM
Whether a new low or not, the number of square kilometers of multi-year sea ice has been drastically reduced; the remaining multi-year sea ice possibly drastically thinned; the surface waters warmed in preparation for the next freeze. Next year will probably be another low year.

The refreeze will start further south on average than most other years, so it might start early, although the warm waters probably mean at a slower than usual rate of progress.
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on February 09, 2017, 11:20:57 PM
So I've done some number crunching using NSIDC data for Jan 26 as current date. 1997 vs 2017.
Looking at each region separately:
bham: now 504k, was 462k on 1997 same date. Fell to 182k at 1997 minimum, declining 280k
wedd: now 1149k, was 1299k on 1997 same date. Fell to 1184k at 1997 minimum, declining 115k
indo: now 277k, was 287k on 1997 same date. Fell to 124k at 1997 minimum, declining 163k
wpac: now 641k, was 569k on 1997 same date. Fell to 426k at 1997 minimum, declining 144k
ross: now 132k, was 661k on 1997 same date. Fell to 348k at 1997 minimum, declining 313k

Using the following guesswork:
bham declines 280k to minimum, same as 1997 though it currently has more ice
wedd declines 120k to minimum, or 220k *
indo declines 163k to minimum, same as 1997
wpac declines 144k to minimum, same as 1997 though it currently has more ice
ross declines 30k to minimum, or 100k **
*** The above can be improved for wedd and ross by checking each year's decline to its own minimum date, instead of using Feb 27 for all. The above can be improved for all regions by looking at other similar years and averaging their declines to minimum instead of just using 1997.

The bottom line gives us the following NSIDC SIE minimum based on regional extrapolation:
Low decline scenario - 737k, down to 1,965k
High decline scenario – 907k, down to 1,795k
Midpoint decline – 822k, down to 1,880k

Following this statistical guesswork, I think <2m has a much higher probability than >2m.
So I've decided to revisit my analysis and find out where it failed.
From Jan 26 to Feb 8:
bham: fell 58k, while 1997 fell by 157k. Average loss for this period is ~120k.
wedd: fell 77k, while 1997 fell by 157k. Average loss for this period is ~140k
indo: fell 75k, while 1997 fell by 104k. Average loss for this period is ~84k.
wpac: fell 24k, while 1997 fell by 107k. Average loss for this period is ~68k.
ross: fell 56k, as expected considering its starting point.
All areas fall within historical variance but on the low side, while 1997 consistently took the high side.
Bottom line, I've made serious statistical errors, using an above average year as a guide, and disregarding the very high variability in antarctic numbers (being used to the arctic). In addition, 2017 somehow produced below-average numbers in all areas for this period, so the prediction was doomed anyway...
Title: Re: Sea Ice Extent around Antarctica
Post by: georged on February 10, 2017, 05:19:17 AM
So I've done some number crunching using NSIDC data for Jan 26 as current date. 1997 vs 2017.
Looking at each region separately:
bham: now 504k, was 462k on 1997 same date. Fell to 182k at 1997 minimum, declining 280k
wedd: now 1149k, was 1299k on 1997 same date. Fell to 1184k at 1997 minimum, declining 115k
indo: now 277k, was 287k on 1997 same date. Fell to 124k at 1997 minimum, declining 163k
wpac: now 641k, was 569k on 1997 same date. Fell to 426k at 1997 minimum, declining 144k
ross: now 132k, was 661k on 1997 same date. Fell to 348k at 1997 minimum, declining 313k

Using the following guesswork:
bham declines 280k to minimum, same as 1997 though it currently has more ice
wedd declines 120k to minimum, or 220k *
indo declines 163k to minimum, same as 1997
wpac declines 144k to minimum, same as 1997 though it currently has more ice
ross declines 30k to minimum, or 100k **
*** The above can be improved for wedd and ross by checking each year's decline to its own minimum date, instead of using Feb 27 for all. The above can be improved for all regions by looking at other similar years and averaging their declines to minimum instead of just using 1997.

The bottom line gives us the following NSIDC SIE minimum based on regional extrapolation:
Low decline scenario - 737k, down to 1,965k
High decline scenario – 907k, down to 1,795k
Midpoint decline – 822k, down to 1,880k

Following this statistical guesswork, I think <2m has a much higher probability than >2m.
So I've decided to revisit my analysis and find out where it failed.
From Jan 26 to Feb 8:
bham: fell 58k, while 1997 fell by 157k. Average loss for this period is ~120k.
wedd: fell 77k, while 1997 fell by 157k. Average loss for this period is ~140k
indo: fell 75k, while 1997 fell by 104k. Average loss for this period is ~84k.
wpac: fell 24k, while 1997 fell by 107k. Average loss for this period is ~68k.
ross: fell 56k, as expected considering its starting point.
All areas fall within historical variance but on the low side, while 1997 consistently took the high side.
Bottom line, I've made serious statistical errors, using an above average year as a guide, and disregarding the very high variability in antarctic numbers (being used to the arctic). In addition, 2017 somehow produced below-average numbers in all areas for this period, so the prediction was doomed anyway...

'Predicting is hard, especially about the future.'
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 10, 2017, 05:28:40 AM
Hold the press!
New number posted by JAXA for SIE around Antarctica is 2,279,405 km2....
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on February 10, 2017, 07:37:22 AM
NSIDC's grid is bigger and it shows polynyas as 100% SIE. Since ice packs drift toward the coast both in East and West,NSIDC's extent may significantly drop
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 10, 2017, 03:11:14 PM
SH NSIDC extent: -51.6k
SH NSIDC area: -53.8k

In the annual minimum rankings, one place advanced in extent and three in area:

Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2011-02-22 2.318847
4 2017-02-09 2.362004
5 1984-02-27 2.381731

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 1985-02-19 1.635733
10 1992-02-23 1.641926
11 1980-02-27 1.646186
12 2002-02-20 1.649281
13 1998-02-26 1.650298
14 2017-02-09 1.662847
15 2011-02-26 1.677629
16 1988-02-24 1.691611
17 1982-02-17 1.713860


No changes in the daily rankings.
Title: Re: Sea Ice Extent around Antarctica
Post by: iceman on February 10, 2017, 03:20:18 PM
   ....
The refreeze will start further south on average than most other years, so it might start early, although the warm waters probably mean at a slower than usual rate of progress.

I'll guess an extent minimum on the 17th, following an uptick around the 13th and a couple days' decline under these conditions:
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 11, 2017, 05:32:27 AM
For Feb. 10th JAXA has posted 2,255,361 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on February 11, 2017, 11:34:34 AM
For Feb. 10th JAXA has posted 2,255,361 km2 for SIE around Antarctica.

http://forum.arctic-sea-ice.net/index.php/topic,230.msg102758.html#msg102758 (http://forum.arctic-sea-ice.net/index.php/topic,230.msg102758.html#msg102758)

worth to cross-link, espen obviously thought it's worth a mention in his arctic thread :-)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 11, 2017, 02:22:44 PM
Big drop down to 2,309 Mn km2. We are, from Wipneus numbers, now on third place behind 1997 and 1993. "Only" about 45K to get an al time low daily minimum (NSIDC numbers).
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 11, 2017, 03:04:52 PM
Indeed, drops everywhere except Ross Sea and Weddel Sea regions. The numbers are:

SH "NSIDC extent": -53.1k
SH "NSIDC area": -56.5k

In the minimum rankings, 2017 extent is now in third place (from four) . A similar drop will be enough to set a record all time (satellite era) low.
"NSIDC area" is now nine ( from 14):


Extent
1 1997-02-27 2.264152
2 1993-02-19 2.280783
3 2017-02-10 2.308883
4 2011-02-22 2.318847

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 2017-02-10 1.606338
10 1985-02-19 1.635733
11 1992-02-23 1.641926
12 1980-02-27 1.646186
13 2002-02-20 1.649281
14 1998-02-26 1.650298



The daily rankings are:

extent SH
2007-02-10 2.902966
1981-02-10 2.878055
1985-02-10 2.794707
2016-02-10 2.752291
1984-02-10 2.726681
2006-02-10 2.640735
2011-02-10 2.574753
1997-02-10 2.487675
1993-02-10 2.462680
2017-02-10 2.308883
area SH
1999-02-10 1.833285
1985-02-10 1.825640
1982-02-10 1.825003
1981-02-10 1.778675
1984-02-10 1.775469
1997-02-10 1.750999
2006-02-10 1.695252
2000-02-10 1.691211
2017-02-10 1.606338
1993-02-10 1.386590
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 11, 2017, 10:52:29 PM
Interstingly, University of Bremen ranks 2017 behind 1993. And from their time series, 2017 will most likely not beat 1993. 1997 is not represented in their graphs so we can't know how if 2017 is ahead or behind that year.

If a record low is going to be possible, that big blob of weak ice in Amundsen Sea needs to a big hit the next couple of days! Earliest date for the freezing onset is February 15 (1994) while the latest date is March 6 (1986).
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 12, 2017, 05:30:25 AM
For Feb. 11th JAXA has posted 2,236,777 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Paddy on February 12, 2017, 08:31:07 AM
Down another bin in the poll... Will this be the final bin, or will it go one lower?
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 12, 2017, 10:49:34 AM
Paddy: It depends on what's going to happen with the loosy ice in Amundsen Sea. From University of Bremens page you can see how fragmentated that ice is.

From CCI_Reanalyzer, cool weather is forecasted for the "northern half" of Antarctica while warmer anomalies will hover in the "southern half" of the continent.

I'm fairly sure we'll see a very early minimum but an overall rather slow freeze up.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on February 12, 2017, 12:51:42 PM
For Feb. 11th JAXA has posted 2,236,777 km2 for SIE around Antarctica.

Here's what that looks like on an extent chart. I've zoomed to the relevant period of ~ 7 weeks, and filtered it to just include the decadal averages, 2016, 2017 and the 3 lowest minima...

NB Remember that the period 2013 - 2015 saw record high extent levels in the Antarctic. We need to wait and see if this is yet another wild fluctuation, or whether the Antarctic is finally settling in to a long-term decline in the same fashion as its boreal cousin.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on February 12, 2017, 01:09:39 PM
The ice in polynya in the south of Weddel sea seems have started to refreeze since it's begining ice-covered without any ice advection, it's really cold there. But everywhere except Weddel sea is really warm and melting momentum continues. The ice pack in the East is weak but extent is higher than usual. Many depends on the wind patterns whether it will spread or compact the ice pack. But anyway it's a record warm warm warm year
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 12, 2017, 01:36:32 PM
Another drop today, down 21K to 2,288 Mn km2 but still third lowest on record.

1997-02-27: 2,264 Mn km2
1993-02-19: 2,281 Mn km2
2017-02-11: 2,288 Mn km2

Tomorrow is another day... Then we'll know if we have surpassed the 1993 minimum or if we have reached the bottom...
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on February 12, 2017, 02:10:29 PM
Another drop today, down 21K to 2,288 Mn km2 but still third lowest on record.

1997-02-27: 2,264 Mn km2
1993-02-19: 2,281 Mn km2
2017-02-11: 2,288 Mn km2

Tomorrow is another day... Then we'll know if we have surpassed the 1993 minimum or if we have reached the bottom...

Here is the Charctic rolling 5-day average. As with the ADS/IJIS chart posted earlier, I've zoomed and filtered so that it just shows 1993, 1997, 2011, 2016 & 2017

The local minima on this chart appear at...

Feb 27 1997;   2.290 million sq kms
Feb 19 1993:   2.312 million sq kms
Feb 25 2011;   2.339 million sq kms

Feb 19 2016;   2.603 million sq kms

The latest single-day NSIDC figure is fractionally lower than the absolute lowest 5-day Charctic value, and the five most recent single-day figures drop monotonically.

It is left to the reader to work out what that may foretell.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 12, 2017, 04:08:11 PM
SH "NSIDC extent": -20.9k
SH "NSIDC area": +35.6k

No change in the minimum rankings, daily or annually.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 13, 2017, 04:33:22 AM
For Feb. 12th JAXA has posted 2,226,844 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 13, 2017, 08:28:03 AM
If the forecast from CCI_Reanalyzer is correct, there might be room for some additional melting up to February 18. By that time, it looks like Weddell Sea will sea a 960 hpa low make its entrance there and bring in some warm air and water. So let's see if might go below the 1997 record! It's time for the final battle! :)

Wipneus & Co: do you have any idea about the "big block" that's is floating freely in the Ross Sea (Univ. of Bremens map) and has done so for more than a month now.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tealight on February 13, 2017, 12:02:17 PM
Wipneus & Co: do you have any idea about the "big block" that's is floating freely in the Ross Sea (Univ. of Bremens map) and has done so for more than a month now.

That is a huge Iceberg. Iceberg B30 to be exact.

On Polarview you can check radar images and track all big icebergs:
http://www.polarview.aq/antarctic (http://www.polarview.aq/antarctic)
Title: Re: Sea Ice Extent around Antarctica
Post by: DavidR on February 13, 2017, 01:48:34 PM
It's GONE! Today's data from NSIDC shows that 2017 has passed the record low extent  in the Antarctic record. Down to  2.246 M km^2 with  1 -> 3 weeks of melt season still left.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 13, 2017, 03:26:09 PM
SH "NSIDC extent": -42.2k
SH "NSIDC area": -33.5k

And indeed an all time (satellite era) low for Antarctic sea ice extent. Here is the top 5:
1 2017-02-12 2.245761
2 1997-02-27 2.264152
3 1993-02-19 2.280783
4 2011-02-22 2.318847
5 1984-02-27 2.381731


It would not be the earliest day on record if the extent happens not to go any lower: that is shared with 1994 that also minimized on 12 Feb.

Area still has some way to go, and particularly 1993 will be hard to beat:

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 1981-03-03 1.588790
8 1997-02-19 1.589288
9 2017-02-10 1.606338


See also attached extent and area graphs.
Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on February 13, 2017, 03:30:01 PM
Particularly hard to almost impossible given the difference and the average rate of decrease..
Title: Re: Sea Ice Extent around Antarctica
Post by: Red on February 13, 2017, 06:38:45 PM
Not sure if this is the right spot to post this but if it moves right it will have an effect on extent. Todays Worldview shot in front of the Shrase shows a new lead going from the toe to open ocean creating a lose piece of ice approx. 30 miles by 200 miles.
https://worldview.earthdata.nasa.gov/?p=antarctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&t=2017-02-13&z=3&v=1298624.539286568,1699629.222484847,1564608.539286568,1871149.222484847
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 13, 2017, 07:08:44 PM
While the DAILY minimum got record low today according to NSIDC numbers, the 5-day average is still above the 1997 record and the next two days will be crucial to determine if we are going to have a "real" record low.

Sea ice in Amundsen Sea has taken the biggest hit the last couple of days.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on February 13, 2017, 08:02:59 PM
SSTs are 3-4 degrees (!) higher than in the same day of 2016 both in Antlantic and Pacific sides. It will struggle to freeze up this year.
Title: Re: Sea Ice Extent around Antarctica
Post by: RoxTheGeologist on February 13, 2017, 08:14:23 PM
Not sure if this is the right spot to post this but if it moves right it will have an effect on extent. Todays Worldview shot in front of the Shrase shows a new lead going from the toe to open ocean creating a lose piece of ice approx. 30 miles by 200 miles.
https://worldview.earthdata.nasa.gov/?p=antarctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&t=2017-02-13&z=3&v=1298624.539286568,1699629.222484847,1564608.539286568,1871149.222484847

That lead is pretty wide too. I'm guessing that runs through fast ice. It shows the lead going through an ice shelf, but I think the boundary of the shelf might be incorrect. 
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on February 13, 2017, 08:15:23 PM
While the DAILY minimum got record low today according to NSIDC numbers, the 5-day average is still above the 1997 record and the next two days will be crucial ...
If the NSIDC extent value for Jan 13th exactly equals that for the 12th (2.246 million sq kms) then the 5-day average will drop to 2.290 million sq kms - exactly equalling the record low from 1997.

Should that unlikely event occur, as long as the extent value on the 14th is lower than that recorded for the 9th Feb (2.362 million sq kms) then the 5-day record low moves into uncharted (or un-Charctic-ed) waters.

As mentioned up-thread, the 2-day smoothed ADS/IJIS/JAXA numbers for extent hit record low levels on the 11th Feb.
Title: Re: Sea Ice Extent around Antarctica
Post by: DavidR on February 14, 2017, 01:52:44 PM
If the NSIDC extent value for Jan 13th exactly equals that for the 12th (2.246 million sq kms) then the 5-day average will drop to 2.290 million sq kms - exactly equalling the record low from 1997.
Jan 13th came in at  2.230 taking the 5 day average to 2.287, breaking the record 5 day  low.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 14, 2017, 02:44:21 PM
SH "NSIDC extent": -15.9k
SH "NSIDC area": -21.6k

This causes 2017 to move to 7th place in annual minimum SH area, skipping two places:

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 1999-02-26 1.577058
7 2017-02-13 1.586773
8 1981-03-03 1.588790
9 1997-02-19 1.589288

Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 14, 2017, 04:46:27 PM
FWIW, I provide some regional sea ice extent pics showing the basins where we might see some additional "melting" until refreezing starts. Will be interesting to see tomorrows number from NSIDC. The 5-day average should drop more given that the first of the past 5 days were higher than the others.

And, given the SSTA from Tropical Tidbits it will be interesting to see if we'll get some real polar amplification by March-April given the warm waters around Antarctica.

Courtesy: University of Bremen (first 2 pics) and Tropical Tidbits/Lewi cowan (third pic)

Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on February 14, 2017, 05:01:26 PM
Today's depressing Charctic image. As before, zoomed and filtered to just show 2017, 2016, 2011, 1997 & 1993.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 15, 2017, 01:42:55 PM
Down to 2,224 Mn km2 and with a 5-day average down to 2,259 Mn km2. The 5-day average will likely go down somewhat the next 1-2 days as I don't see a 75K uptick likely.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 15, 2017, 02:59:20 PM
SH "NSIDC extent": -5.6k
SH "NSIDC area": +16.4k

Daily area now third lowest:

area SH
1984-02-14 1.731623
1980-02-14 1.727033
2002-02-14 1.720928
2006-02-14 1.717069
1999-02-14 1.687074
1981-02-14 1.681987
1997-02-14 1.676127
2017-02-14 1.603165
2000-02-14 1.585860
1993-02-14 1.303875
Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on February 15, 2017, 03:20:25 PM
May end up second lowest.
Title: Re: Sea Ice Extent around Antarctica
Post by: dingojoe on February 15, 2017, 06:44:36 PM
Still quite a bit of fast ice continuing to break down along the NE and SE quadrants.  Those coastlines are at lower latitudes so melt could continue along these areas into March.
Title: Re: Sea Ice Extent around Antarctica
Post by: be cause on February 15, 2017, 07:02:41 PM
Hi Bill .. any chance of moving the 'details box' so that it doesn't hide the detail ? Thanks for all the details you post :)
                         bc
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on February 15, 2017, 08:35:00 PM
Hi Bill .. any chance of moving the 'details box' so that it doesn't hide the detail ? Thanks for all the details you post :)
                         bc
Hi BC,

Assuming I'm the "bill" in question, the slider underneath any chart can be used to slide it to the left in order to see any temporarily hidden text. As regards the ADS/JAXA/IJIS chart and the NSIDC Charctic equivalent, I have deliberately left them undoctored (apart from the zooming/filtering) such that anyone could create an identical image for themselves.

Does that help, or did I misinterpret your meaning?
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on February 15, 2017, 08:46:49 PM
Being a fan of rolling 12-month averages, I thought I'd do a quick analysis on the NSIDC monthly EXTENT numbers for the Antarctic. In order to keep it simple to start with, I applied equal weighting to each month. Obviously that gives slightly more weight to the month of February, but it's only a second order effect.

I then used the RANK feature in Excel, and displayed this as a "Heat Chart", as shown below. So far, there have been 448 of these rolling 12-month periods.

FEATURES TO NOTE:

1) As anyone would expect, the overall trend is one of ice growth.

2) There are repeated horizontal "stripes", indicating that this growth is anything but monotonic.

3) From the 12-month period ending April 2012 until the equivalent period ending April 2016, every data point was in the highest quartile.

4) From every such period from May 2013 until February 2016, every data point was in the highest 10-percentile.

5) During 2016 & 2017, the average has dropped precipitously at an unmatched rate, such that the two most recent data points are in the lowest 5-percentile.

6) Looking at the "December" column, it can be seen that 2016 had the second lowest end-of-year average in the entire dataset.


Using this "rough" assessment as a guide, a rolling 365-day average can be carried out on the areas of interest. (NB There are some problems with doing a blanket 365-average. In addition to some significant data drops, the sampling rate alters part way through the dataset . This is hardly insurmountable, but I'm just lazy!)

The current 365-day average extent (data as at Feb 14th 2017) is 11.056 million sq kms.

Every 365-day average ending during the entire period from early January 1987 to mid-March 1987 was lower than this, with a local minimum of ~ 11.038 million sq kms. At the present rate of decline in the 365-day average - slightly in excess of 12,000 sq kms over the last 10 days - this figure could possibly be surpassed by the end of February.

Similarly, every 365-day average ending during the period end-June 1980 until mid-October 1980 was lower than the current value of 11.056 million sq kms. The local minimum during that period dropped to 10.969 millions sq kms, and there were about ~ 62 days on which the average was below 11 million sq kms. At the present rate of decline, the 365-day rolling average might drop below 11 by early April, but would take till near the end of that month to reach record-low territory.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 16, 2017, 09:24:15 AM
Even lower extent and area numbers are unlikely today. Calculating from Uni Hamburg ASI AMSR2 sea ice concentration data:

Date: 2017-02-15 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                327.0  +33.2                1091.2   +0.4
                Indian Ocean           West Pacific Ocean
                177.8   -1.7                 496.6  +15.8
                    Ross Sea                        Total
                 76.7   -6.8                2169.4  +40.9

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                260.1  +38.6                 979.6   -7.9
                Indian Ocean           West Pacific Ocean
                152.7   -1.0                 414.5   +4.8
                    Ross Sea                        Total
                 64.3   -3.9                1871.2  +30.6
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 16, 2017, 02:35:22 PM
SH "NSIDC extent": +29.5k
SH "NSIDC area": +24.5k

Area is now the 4th lowest:

area SH
1980-02-15 1.706625
2006-02-15 1.701121
2002-02-15 1.698856
1996-02-15 1.686381
1999-02-15 1.684981
1997-02-15 1.643263
2017-02-15 1.627697
1981-02-15 1.622265
2000-02-15 1.590006
1993-02-15 1.292263
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 16, 2017, 08:27:30 PM
Looking at CCI_Reanalyzers forecast for the next 7 days reveals the possibility of a few more days with warmer than average temps in the areas with the best chance to see some additional compaction or bottom melting before refreezing takes place.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 17, 2017, 12:18:27 AM
Seconds ago I was watching CNN, and across the bottom of the screen it read, " Antarctic Sea Ice shrinks to a new low."

P.S. Checked online and voila.

www.cnn.com/2017/02/16/world/antarctica-sea-ice-record-low/index.html (http://www.cnn.com/2017/02/16/world/antarctica-sea-ice-record-low/index.html)
Title: Re: Sea Ice Extent around Antarctica
Post by: DavidR on February 17, 2017, 11:00:25 AM
Not sure if this is the right spot to post this but if it moves right it will have an effect on extent. Todays Worldview shot in front of the Shrase shows a new lead going from the toe to open ocean creating a lose piece of ice approx. 30 miles by 200 miles.
https://worldview.earthdata.nasa.gov/?p=antarctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&t=2017-02-13&z=3&v=1298624.539286568,1699629.222484847,1564608.539286568,1871149.222484847

That lead is pretty wide too. I'm guessing that runs through fast ice. It shows the lead going through an ice shelf, but I think the boundary of the shelf might be incorrect.
Mmm that  section of Ice has really broken up in the past few days.
Title: Re: Sea Ice Extent around Antarctica
Post by: charles_oil on February 17, 2017, 08:48:16 PM
After the CNN one there was an article on Antarctica on Al Jazeera too today

http://www.aljazeera.com/blogs/editors-blog/2017/01/wild-antarctica-scientists-robots-pancake-ice-170131140037171.html (http://www.aljazeera.com/blogs/editors-blog/2017/01/wild-antarctica-scientists-robots-pancake-ice-170131140037171.html)

Though I think this may be the earlier report at end of Jan.

In todays film are taking cores etc on the Mertz Glacier
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 18, 2017, 05:39:02 AM
 This probably signals the end of melt season, short of a drastic event.
 From the 14th of Feb. to the 15th.
CLICK IMAGE PLEASE
 (https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on February 18, 2017, 12:53:12 PM
12215,2017,02,11,1208044800,2236777
12216,2017,02,12,1208131200,2226844
12217,2017,02,13,1208217600,2222327 lowest so far
12218,2017,02,14,1208304000,2226896
12219,2017,02,15,1208390400,2230736
12220,2017,02,16,1208476800,2232124
12221,2017,02,17,1208563200,2224767 2.4k above lowest

Too close to lowest to call it yet.

But I think we can call global extent and area minimums past per Wipneus' charts in Daily graphs.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 19, 2017, 05:30:39 AM
For Feb. 18th JAXA has reported 2,199,214 km2 for SIE around Antarctica.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tealight on February 19, 2017, 09:21:09 PM
Wipneus replacement post.

SH "NSIDC extent": -49.6k
SH "NSIDC area": -35.04k

This causes 2017 to move to 6th place in annual minimum SH area, skipping one place:

Extent
1 2017-02-18 2.220714
2 1997-02-27 2.264152
3 1993-02-19 2.280783
4 2011-02-22 2.318847

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2000-02-18 1.561033
5 2006-03-04 1.565059
6 2017-02-18 1.565366
7 1999-02-26 1.577058
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on February 19, 2017, 09:33:36 PM

Extent
1 2017-02-02 2.220714

18 Feb 2017 I assume.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tealight on February 19, 2017, 09:48:18 PM

Extent
1 2017-02-02 2.220714

18 Feb 2017 I assume.

Yes 18th Feb, thanks for spotting.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 20, 2017, 05:33:25 AM
For Feb. 19th JAXA has posted 2,192,847 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 20, 2017, 06:37:58 PM
For Feb 19, NSIDC reports a new record low value at 2,201 Mn km2 and a new record 5-day average at 2,242 Mn km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Blizzard92 on February 20, 2017, 08:27:11 PM
A bit hard to see, but here's the latest NSIDC daily extent with added quartile ranges... http://sites.uci.edu/zlabe/antarctic-sea-ice-extentconcentration/ (http://sites.uci.edu/zlabe/antarctic-sea-ice-extentconcentration/)
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 21, 2017, 02:17:38 PM
A new record low for Feb. 20. Down to 2,191 Mn km2 and a 5-day average down to 2,229 Mn km2, also a new record low value. If no refreezing occurrs for today and tomorrow, we might go down as low as 2,20 Mn km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: georged on February 21, 2017, 10:10:39 PM
A new record low for Feb. 20. Down to 2,191 Mn km2 and a 5-day average down to 2,229 Mn km2, also a new record low value. If no refreezing occurrs for today and tomorrow, we might go down as low as 2,20 Mn km2.

What are we looking at for area?
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on February 21, 2017, 11:23:11 PM
It seems the extent have reached the annual minimun since the ice pack drift outward the coast in the Weddel sea and opened polynyas freeze up rapidly. Animation 18-21Feb
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 22, 2017, 06:58:05 AM
Pavel: could be, but the freezing in Weddell seems to be counteracted by melting/compacting in other areas so it's possible that we could go another small bin down before the real growth starts. But yes, I woldn't be surprised if we will see upticks from now and onward. Weddell sea is cold right now.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 22, 2017, 06:18:41 PM
An uptick in the daily value to 2,215 Mn km2 but a dip downward in the 5-day average to 2,220 Mn km2. If no significant uptick is reported tomorrow we should dip another bin down in the 5-day average. But, given the uptick, the forecast and the state of the Weddell Sea iit's possible that we have 1-2 more days until more sigificant refreezing starts, particularly from Friday and beyond.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on February 22, 2017, 07:59:22 PM
Here's what the above latest developments mean in terms of the 5-day NSIDC Charctic.

I've zoomed to where the current action is, and I've filtered out most of the "noise" years. As usual, I've included 2016 & 2017 (natch), as well as what had been, until recently, the three years with the lowest mins - 1997, 1993 & 2011.

I've added 2013, 2014 & 2015 just to show the spread from highest <> lowest annual minimums.

I've also added 2006 and 1980, as, between them, these represent "lowest daily values" from about the 12th March onward. Another reason for some interest in 1980, is because that is when the lowest annual average occurred. (So far)

Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 23, 2017, 03:11:40 PM
SH "NSIDC extent": -19k4k
SH "NSIDC area": -33.0k

Among the annual minimums area went up two places and is now 4th lowest.

Area
1 1993-02-26 1.248163
2 1984-02-27 1.509585
3 1996-02-25 1.535481
4 2017-02-22 1.556394
5 2000-02-18 1.561033
6 2006-03-04 1.565059


The area graph is attached.

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 24, 2017, 05:39:40 AM
For Feb. 23rd JAXA has posted 2,167,669 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 24, 2017, 04:38:26 PM
For Feb 23, NSIDC reports a new daily record low at 2,156 Mn km2. The 5-day average dropped to 2,192 Mn km2. The latter index might go even lower tomorrow unless a significant growth is seen. I believe that todays big drop is due to that a lot of the fragmented ice in Amundsen sea went below 15%. Wipneus might know if that was the case or not.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 24, 2017, 04:52:50 PM
I believe that todays big drop is due to that a lot of the fragmented ice in Amundsen sea went below 15%. Wipneus might know if that was the case or not.

Well, the details are thus:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-02-23 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        260.8  -11.3  -193.7        1164.7   +3.5   -31.3
                Indian Ocean           West Pacific Ocean
        147.1   -0.0   -42.3         519.1  -26.7  +158.8
                    Ross Sea                        Total
         64.8   -4.2  -620.5        2156.5  -38.8  -729.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        144.0   -8.8  -118.4         958.0   -6.6   +55.5
                Indian Ocean           West Pacific Ocean
         73.7   -1.7   -24.1         300.3  -34.3   +83.5
                    Ross Sea                        Total
         26.2   -2.8  -334.9        1502.3  -54.1  -338.4



The biggest losses are in the West Pacific Ocean region.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 24, 2017, 05:20:12 PM
The area losses also bring a new annual minimum, moving 2017 tot the second place where it will probably stay for quite a while.

Extent
1 2017-02-23 2.156456

Area
1 1993-02-26 1.248163
2 2017-02-23 1.502254
3 1984-02-27 1.509585
4 1996-02-25 1.535481



Also in the daily ranking area is second lowest after the remarkable 1993:

area SH
2011-02-23 1.702829
2006-02-23 1.664207
1992-02-23 1.641926
1999-02-23 1.635909
1981-02-23 1.625223
1997-02-23 1.613904
1984-02-23 1.607507
1996-02-23 1.579022
2017-02-23 1.502254
1993-02-23 1.291779
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on February 24, 2017, 05:28:20 PM
Each time one thinks the melting is over, off we go again. SST anomalies at 70 degrees and north of that still quite impressive. One waits to see if refreezing will be late and slow  and then if it is but a burp or a real change down there.

Patience is a virtue but sorely tested.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 24, 2017, 05:52:12 PM
Last days that the minimums set are in March.

Extent has the latest: 6 March 1986, but the second latest extent was 27 Feb 1984, 1991 and 1997.

Area has two March dates: 2006-03-04 and 1981-03-03. Before that is the pack, 17-27 February.

Here are the sorted lists (1978 has only data from November and December):


SH EXTENT
30 1994-02-12 3.082862
25 2010-02-16 2.842209
27 1979-02-16 2.873193
10 2016-02-17 2.577755
37 2003-02-17 3.625715
11 2000-02-18 2.582475
23 2005-02-18 2.803882
35 2015-02-18 3.532464
3 1993-02-19 2.280783
13 1985-02-19 2.601560
16 1981-02-19 2.675476
19 2007-02-19 2.722703
34 2001-02-19 3.440951
38 2013-02-19 3.678996
6 2006-02-20 2.486597
17 2002-02-20 2.696900
18 1999-02-20 2.707231
20 1989-02-20 2.722912
29 1987-02-20 2.996257
32 2004-02-20 3.259284
39 2008-02-20 3.691767
36 2014-02-21 3.548484
4 2011-02-22 2.318847
15 2009-02-22 2.670964
22 1990-02-22 2.784345
26 1982-02-22 2.863992
1 2017-02-23 2.156456
7 1992-02-23 2.492393
24 1983-02-23 2.816138
31 2012-02-23 3.111095
14 1988-02-24 2.638617
33 1995-02-24 3.329888
8 1980-02-25 2.516067
12 1996-02-25 2.597335
21 1998-02-25 2.771514
2 1997-02-27 2.264152
5 1984-02-27 2.381731
9 1991-02-27 2.553553
28 1986-03-06 2.952849
40 1978-12-31 7.283008
SH AREA
37 2015-02-14 2.414870
17 1982-02-17 1.713860
18 2016-02-17 1.729589
30 1995-02-17 2.002174
5 2000-02-18 1.561033
32 1994-02-18 2.098845
9 1997-02-19 1.589288
10 1985-02-19 1.635733
25 2007-02-19 1.821313
35 2001-02-19 2.286595
38 2014-02-19 2.423633
13 2002-02-20 1.649281
27 1979-02-20 1.926174
29 2010-02-20 1.933016
34 2008-02-20 2.203494
36 2013-02-20 2.389945
26 1989-02-21 1.841981
22 2009-02-22 1.794061
31 1990-02-22 2.026988
33 2004-02-22 2.154999
2 2017-02-23 1.502254
11 1992-02-23 1.641926
28 2012-02-23 1.931870
16 1988-02-24 1.691611
21 1987-02-24 1.781372
4 1996-02-25 1.535481
19 1983-02-25 1.738279
23 1991-02-25 1.797485
24 2005-02-25 1.798750
1 1993-02-26 1.248163
7 1999-02-26 1.577058
14 1998-02-26 1.650298
15 2011-02-26 1.677629
3 1984-02-27 1.509585
12 1980-02-27 1.646186
20 1986-02-27 1.763319
39 2003-02-27 2.448344
8 1981-03-03 1.588790
6 2006-03-04 1.565059
40 1978-12-31 4.831456

Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on February 24, 2017, 07:08:44 PM
The area losses also bring a new annual minimum, moving 2017 tot the second place where it will probably stay for quite a while.

Extent
1 2017-02-23 2.156456

Area
1 1993-02-26 1.248163
2 2017-02-23 1.502254
3 1984-02-27 1.509585
4 1996-02-25 1.535481



Also in the daily ranking area is second lowest after the remarkable 1993:

area SH
2011-02-23 1.702829
2006-02-23 1.664207
1992-02-23 1.641926
1999-02-23 1.635909
1981-02-23 1.625223
1997-02-23 1.613904
1984-02-23 1.607507
1996-02-23 1.579022
2017-02-23 1.502254
1993-02-23 1.291779


Quite an interesting race...
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 25, 2017, 05:10:12 PM
Another daily record low and another record low 5-day average. SIE for February 24 was down to 2,145 Mn km2 while the 5-day average was down to 2,180 Mn km2. While I've hard to imagine any further extent loss the next couple of days, the 5-day average might dip down depending on the next few days SIE.

What's interesting is that the University of Bremen sea ice graph still have 1993 as being the record low year in their graph. See the graph at: https://seaice.uni-bremen.de/data/amsr2/today/extent_s_running_mean_amsr2_regular.png (https://seaice.uni-bremen.de/data/amsr2/today/extent_s_running_mean_amsr2_regular.png)
Title: Re: Sea Ice Extent around Antarctica
Post by: Andre on February 25, 2017, 08:43:25 PM
What's interesting is that the University of Bremen sea ice graph still have 1993 as being the record low year in their graph. See the graph at: https://seaice.uni-bremen.de/data/amsr2/today/extent_s_running_mean_amsr2_regular.png (https://seaice.uni-bremen.de/data/amsr2/today/extent_s_running_mean_amsr2_regular.png)

I would guess that as long as it isnt clear, when the minimum will be reached this year and what the new record will be, they will wait to make any changes. Otherwise, they would have to update the record every day we see another SIE drop. Probably a lot easier to just wait a few weeks, make sure we are well past the minimum and then update the new record low number.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 26, 2017, 02:56:49 PM
Another daily record low, now down to 2,135 Mn km2 and a 5-day average moving down to 2,169 Mn km2... Any area changes today?
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 26, 2017, 05:23:47 PM
. Any area changes today?

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-02-25 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        247.6   +4.4  -204.6        1176.2   +5.7   -28.0
                Indian Ocean           West Pacific Ocean
        139.8   -8.0   -47.2         504.9  -16.5  +144.4
                    Ross Sea                        Total
         66.2   +4.7  -645.6        2134.8   -9.8  -781.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        139.6   +0.4  -120.3         986.3  +24.7   +77.0
                Indian Ocean           West Pacific Ocean
         68.1   -5.7   -27.3         324.3   -7.5  +109.9
                    Ross Sea                        Total
         26.6   -0.4  -350.8        1544.9  +11.6  -311.4
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 27, 2017, 08:50:03 AM
Todays sea ice map of Antarctica reveals some newly formed ice in the Ross Sea. I think this is it and that the final daily minimum will be 2,135 Mn km2. I expect a small uptick today.

However, it's possible that the 5-day average might go somewhat lower than yesterdays reported 2,169 Mn km2.

Finally, in case you haven't seen it, the thickness map that is easily found for the Arctic basin also exists for the Antarctica. There are two links: https://seaice.uni-bremen.de/data/smos/png/ (https://seaice.uni-bremen.de/data/smos/png/) It's also found at: https://seaice.uni-bremen.de/databrowser/ (https://seaice.uni-bremen.de/databrowser/)

Here is the Antarctica thickness map for February 26: (https://seaice.uni-bremen.de/data/smos/png/20170226_hvsouth_rfi_l1c.png) Courtesy to University of Bremen.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 27, 2017, 09:12:43 AM
It is still a big continent. Extent and area calculated from Uni Hamburg SIC still dropping. New minimum for 2016 extent:

Regional Arctic Sea Ice Extent and Area calculated from Uni Hamburg ASI AMSR2 concentration data
See uh_am2_ant.txt for more details
Date: 2017-02-26 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                220.3  -10.5                1196.6   -0.7
                Indian Ocean           West Pacific Ocean
                147.3   -6.5                 435.4   -5.8
                    Ross Sea                        Total
                 84.5   +5.7                2084.2  -17.8

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                183.7   -6.4                1078.5   -7.6
                Indian Ocean           West Pacific Ocean
                121.6   -8.3                 371.5   -4.1
                    Ross Sea                        Total
                 62.3   +1.8                1817.5  -24.8
Title: Re: Sea Ice Extent around Antarctica
Post by: iceman on February 27, 2017, 11:49:09 AM
It is still a big continent. Extent and area calculated from Uni Hamburg SIC still dropping. ...

Amazing.  I was expecting an early minimum, following the wind-driven compaction earlier in the season.  Maybe accumulated insolation is still taking its toll.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 27, 2017, 01:54:24 PM
NSIDC sees it slightly different:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-02-26 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        251.7   +4.1  -200.1        1179.2   +3.0   -30.3
                Indian Ocean           West Pacific Ocean
        144.1   +4.3   -42.3         513.4   +8.5  +152.0
                    Ross Sea                        Total
         71.6   +5.4  -657.4        2160.0  +25.3  -778.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        133.8   -5.8  -125.5         976.9   -9.4   +63.2
                Indian Ocean           West Pacific Ocean
         73.6   +5.5   -21.0         313.2  -11.1   +99.6
                    Ross Sea                        Total
         27.1   +0.5  -360.6        1524.6  -20.3  -344.3


NSIDC extent and area minimums did not change:

Extent
1 2017-02-25 2.134752

Area
1 1993-02-26 1.248163
2 2017-02-23 1.502254
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on February 28, 2017, 04:43:29 AM
For Feb. 27th JAXA has posted 2,152,483 km2 for SIE around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 28, 2017, 08:24:18 AM
Interesting TT! Todays map from UiB shows continued refreezing in Ross Sea. From Bremens graph it's a really tight race between 2017 and 1993 about the record. Should be another small uptick today from NSIDC given the newly formed ice in Ross Sea. Maybe other areas counteract these numbers by melting/compaction.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 28, 2017, 12:52:57 PM
Maybe other areas counteract these numbers by melting/compaction.

Some do, resulting in very small net losses:

Regional Arctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-02-27 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                232.2   -7.5                1188.9  -22.2
                Indian Ocean           West Pacific Ocean
                148.5   +0.8                 448.9  +11.4
                    Ross Sea                        Total
                108.4  +15.3                2126.9   -2.3

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                190.8   -2.7                1070.5  -18.3
                Indian Ocean           West Pacific Ocean
                119.1   +0.6                 377.1   +8.4
                    Ross Sea                        Total
                 75.6   +7.6                1833.1   -4.3
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on February 28, 2017, 01:53:26 PM
A second opinion from NSIDC data:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-02-27 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        216.8  -34.9  -235.5        1181.1   +1.9   -34.9
                Indian Ocean           West Pacific Ocean
        142.3   -1.8   -44.1         494.0  -19.4  +131.5
                    Ross Sea                        Total
         74.9   +3.3  -672.9        2109.1  -50.9  -855.9

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        131.1   -2.8  -128.3         980.5   +3.6   +61.0
                Indian Ocean           West Pacific Ocean
         73.3   -0.3   -20.7         299.8  -13.4   +86.5
                    Ross Sea                        Total
         26.6   -0.5  -373.0        1511.2  -13.3  -374.4


Extent sets a new lower minimum.
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on February 28, 2017, 05:50:39 PM
Wow. Still not over  :o
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on February 28, 2017, 06:25:48 PM
No Oren, the fat lady hasn't sung yet :) But I would be extremely surprised if we dipped below 2 Mn km2 at this time of year. Depending on the weather conditions the next few days it's possible that the 5-day average may reach its minimum March, something that's not too common.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 01, 2017, 08:13:42 AM
It is going to be a late minimum according to sea ice concentration data from Uni Bremen:


Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-02-28 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                223.1  -10.1                1199.1   +8.2
                Indian Ocean           West Pacific Ocean
                151.1   +1.1                 429.1  -21.3
                    Ross Sea                        Total
                 98.3  -10.7                2100.8  -32.8

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                184.3   -7.1                1082.4  +10.2
                Indian Ocean           West Pacific Ocean
                122.9   +2.8                 367.1  -11.3
                    Ross Sea                        Total
                 70.3   -5.7                1827.1  -11.1
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 01, 2017, 09:05:55 AM
Wipneus: do you know if the extent value from Uni Bremen lower than the minimum back in 1993 and 1997 was?
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 01, 2017, 10:08:16 AM
Wipneus: do you know if the extent value from Uni Bremen lower than the minimum back in 1993 and 1997 was?

The data from Uni Bremen that I use is AMSR2, so only since mid July 2012.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 01, 2017, 10:35:42 AM
The only other (besides NSIDC) time series that I have going that far back is from IFREMER (French Research Institute for Exploitation of the Sea). It is using the ASI algorithm, so higher resolution and as different as can be. Available since 1992.

But, the IFREMER data says basically the same as NSIDC: extent in 2017 is significantly lower (200k-300k) than any other year. Only 1993 area is lower than 2017 (by 200k or so).
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 01, 2017, 01:59:23 PM
NSIDC sees very small changes that could well be reversed with the update tomorrow:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-02-28 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        221.2   +4.5  -232.3        1181.5   +0.4   -42.4
                Indian Ocean           West Pacific Ocean
        146.0   +3.7   -40.7         489.9   -4.1  +126.2
                    Ross Sea                        Total
         70.2   -4.7  -699.8        2109.0   -0.1  -889.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        131.3   +0.2  -128.8         981.2   +0.7   +54.2
                Indian Ocean           West Pacific Ocean
         74.7   +1.4   -18.9         299.4   -0.4   +86.4
                    Ross Sea                        Total
         25.8   -0.8  -387.7        1512.4   +1.1  -394.8
Title: Re: Sea Ice Extent around Antarctica
Post by: iceman on March 01, 2017, 03:02:04 PM
NSIDC sees very small changes that could well be reversed with the update tomorrow:
   ....
If the extent number stands, that would make 2017 second-latest by the thinnest of margins (per your sorted list in post #507 upthread).
     Quite a reversal from 2015, which was the fourth-earliest on record.
Title: Re: Sea Ice Extent around Antarctica
Post by: Andre on March 02, 2017, 06:53:25 AM
March 1st, JAXA reporting 2,147,345 km2. Another small drop and a new record low.

Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 02, 2017, 09:03:00 AM
Area/extent calculated from Uni Bremen's sea ice concentration reach new lows :

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-01 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                223.6   -0.9                1197.4   -2.8
                Indian Ocean           West Pacific Ocean
                131.7  -20.5                 446.7  +15.8
                    Ross Sea                        Total
                102.8   +3.3                2102.1   -5.1

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                183.2   -2.0                1064.0  -19.2
                Indian Ocean           West Pacific Ocean
                109.1  -14.5                 379.9  +11.3
                    Ross Sea                        Total
                 69.8   -1.4                1806.0  -25.8
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 02, 2017, 09:23:27 AM
interesting Wipneus! :) Let's see if NSIDC also comes up with a new record low value today!

If the NSIDC minimum (5-day avg) is occurring now in March it will only be the fifth time this happens. The earlier occurrences are: 1986 (March 6), 2003 (March 3), 1991 (March 2) and 1980 (March 1). The case from 1980 doesn't contain the value for the leap day. In 1986, the values were also given for every second day but the minimum then was so late that there can be no doubts it was absolutely the latest such and occurred in March.

Daily NSIDC values from the ftp adress are available from August 1987. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/south/daily/data/S_seaice_extent_daily_v2.1.csv (http://ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/south/daily/data/S_seaice_extent_daily_v2.1.csv)

I hope I haven't got something wrong here!
Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on March 02, 2017, 11:18:24 AM
Feb. anomoly from http://nsidc.org/data/bist/bist.pl?annot=1&legend=1&scale=100&tab_cols=2&tab_rows=2&config=seaice_index&submit=Refresh&mo0=01&hemis0=S&img0=anom&mo1=02&hemis1=S&img1=anom&year0=2017&year1=2016 (http://nsidc.org/data/bist/bist.pl?annot=1&legend=1&scale=100&tab_cols=2&tab_rows=2&config=seaice_index&submit=Refresh&mo0=01&hemis0=S&img0=anom&mo1=02&hemis1=S&img1=anom&year0=2017&year1=2016)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FuqBtn%2F82cd7de4a9.jpg&hash=c3d6cda8f1fdf9e7e33b61ae7e5dd13a)
+ yesterdays image from http://www.seaice.dk/latest/yesterdays-amsr2-s-mos.jpg (http://www.seaice.dk/latest/yesterdays-amsr2-s-mos.jpg) click the link for a more detailed image [this will change daily]
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fpuu.sh%2FuqC41%2Fac68b23808.jpg&hash=4275daf3676f99a80f2334e4c9db0546)
I'm beggining to wonder if these small daily losses will stretch towards the equinox, or even beyond. There may be just enough circulation of waters by the coast to inhibit freezing, and without ice cover to dampen waves much too much turbulence.
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on March 02, 2017, 01:35:42 PM
So statistically indistinguishable from latest minimum on record for both JAXA and NSIDC daily because the shape of the minimum in 1986 means the minimum might have occurred on 29th Feb, 1st March or 2nd of March (3rd also possible but seems unlikely)

2.075 on daily NSIDC is new low as is 2147345 for JAXA.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 02, 2017, 01:45:13 PM
On both extent and area:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-01 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        217.5   -3.7  -232.3        1185.5   +4.0   -49.8
                Indian Ocean           West Pacific Ocean
        109.4  -36.6   -76.4         496.6   +6.7  +129.2
                    Ross Sea                        Total
         65.8   -4.4  -730.5        2074.9  -34.0  -959.7

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        128.6   -2.6  -128.5         982.9   +1.7   +43.8
                Indian Ocean           West Pacific Ocean
         56.1  -18.6   -37.1         298.5   -0.9   +83.7
                    Ross Sea                        Total
         22.9   -3.0  -407.9        1489.0  -23.4  -445.9
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 02, 2017, 03:49:05 PM
So statistically indistinguishable from latest minimum on record for both JAXA and NSIDC daily because the shape of the minimum in 1986 means the minimum might have occurred on 29th Feb, 1st March or 2nd of March (3rd also possible but seems unlikely)

2.075 on daily NSIDC is new low as is 2147345 for JAXA.

By coincidence I have just asked on stupid questions what is the accuracy of these measurements. Down to 1km2 or even 1000km2 obviously spurious accuracy ?
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on March 02, 2017, 05:12:47 PM
So statistically indistinguishable from latest minimum on record for both JAXA and NSIDC daily because the shape of the minimum in 1986 means the minimum might have occurred on 29th Feb, 1st March or 2nd of March (3rd also possible but seems unlikely)

2.075 on daily NSIDC is new low as is 2147345 for JAXA.

By coincidence I have just asked on stupid questions what is the accuracy of these measurements. Down to 1km2 or even 1000km2 obviously spurious accuracy ?

That is a more difficult question than my simplistic we just don't know when 1986 minimum was due to reporting only every other day.

The curves look quite smooth for SH compared to NH, which suggests that the uncertainty of the date of minimum is not all that high but yes 1000km2 accuracy does not seem likely. Sorry that isn't much of an answer.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 02, 2017, 06:17:15 PM
In a "best case scenario" we might have 1-2 days with even lower values due to intrusion of warm waters and compaction. As we already are lowest on record, I tink it would be "exciting" if we could bottom out at 1,99 Mn km2. That would require another 76K drop.

But given the unusually low extent from November and onward we can be pretty sure that tremendeous amounts of heat have entered into the Southern Ocean this melting season. Even if the refreezing is imminent the damage is already done. And I won't be surprised if we are going to see some decent polar amplification by March-April around Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 02, 2017, 06:41:33 PM
(...) what is the accuracy of these measurements. Down to 1km2 or even 1000km2 obviously spurious accuracy ?

I would rather not call these measurements. The satellite sensor measures microwave brightness's. These are inputs to a calculation (perhaps involving other inputs) that delivers sea ice concentration on a grid with a certain cell size. Sometimes it stops there, sometimes extent is calculated (possibly with more corrections). In only a few cases area is calculated.

The first step, satellite measurements, have error levels specified.
The second only in a few cases. Jaxa is close to 10%, ASI (Hamburg, Bremen) may be 15%. Figures from the top of my head.
I cannot remember seeing extent or even area accuracy being estimated. Full error bars would probably measured in 100,000's of sqkm. Mostly systematic (gridsize etc.) , some part random noise.

The day-to-day changes (sticking to one calculation e.g. Jaxa) will  be more reliable. Maybe a just a few k in case of the Antarctic minimum as crandles observed.
With this in mind, I think the conclusion that the minimum can be called "rather late" is robust (with the possibility that it may later become "very late").

For year to year comparisons you need a time series that has been carefully compiled for this purpose. Only NSIDC can really be used. The IFREMER series uses the same satellite sensors as NSIDC (but other microwave bands) is available since 1992. From those I would say that lowest extent minimum since 1979 seems also robust. 1993 seems an odd year as it has a relatively very low area minimum but not by extent.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 02, 2017, 08:16:29 PM
Hullo ASIF Guv'nor. I actually engaged brain to read the notes on Jaxa. Confirms up to 10 % error on SIC data. BUT !
In statistics often an individual datum can have a very high error. But when enough bits of data are brought together the error of the sum of the entire data is reduced to virtualy zero.

I find it hard to believe that the current Jaxa measurement of Antarctic SIE is 2147 km2 '000 +/- 10 %. As they say - I think we need to know.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 03, 2017, 08:23:36 AM
Increases in the Bremen sea ice concentration grids

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-02 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                238.8  +13.9                1238.0  +39.2
                Indian Ocean           West Pacific Ocean
                128.0   -5.0                 456.6   +8.4
                    Ross Sea                        Total
                 81.1  -22.1                2142.5  +34.4

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                192.9   +8.8                1095.6  +30.7
                Indian Ocean           West Pacific Ocean
                104.8   -5.3                 382.6   +1.5
                    Ross Sea                        Total
                 57.9  -12.2                1833.8  +23.5
.

Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 03, 2017, 08:36:34 AM

I find it hard to believe that the current Jaxa measurement of Antarctic SIE is 2147 km2 '000 +/- 10 %.

Nobody that I know of says so. Extent calculation makes that grid cells with concentration > 25% or < 5% will have no (zero) error. In the marginal zone ( 5%<sic<25%) random errors will cancel out, but systematic (too low or too high values ) won't. Especially in the Arctic false coastal ice is surprisingly large ( my coastal correction today in UH calculation is 262k extent and 157k area).
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 03, 2017, 11:24:20 AM
So statistically indistinguishable from latest minimum on record for both JAXA and NSIDC daily because the shape of the minimum in 1986 means the minimum might have occurred on 29th Feb, 1st March or 2nd of March (3rd also possible but seems unlikely)

2.075 on daily NSIDC is new low as is 2147345 for JAXA.

By coincidence I have just asked on stupid questions what is the accuracy of these measurements. Down to 1km2 or even 1000km2 obviously spurious accuracy ?

This very valid question is at least partially addressed by the NSIDC in their FAQ section.

https://nsidc.org/arcticseaicenews/faq/#error_bars

The relevant bit reads as follows...

"We estimate error based on accepted knowledge of the sensor capabilities and analysis of the amount of “noise,” or daily variations not explained by changes in weather variables. For average relative error, or error relative to other years, the error is approximately 20,000 to 30,000 square kilometers (7,700 to 11,600 square miles), a small fraction of the total existing sea ice. For average absolute error, or the amount of ice that the sensor measures compared to actual ice on the ground, the error is approximately 50 thousand to 1 million square kilometers (19,300 to 386,100 square miles), varying over the year. During summer melt and freeze-up in the fall, the extent may be underestimated by 1 million square miles; during mid and late winter before melt starts, the error will be on the low end of the estimates. It is important to note that while the magnitude of the error varies through the year, it is consistent year to year. This gives scientists high confidence in interannual trends at a given time of year.

The absolute error values may seem high, but it is important to note that each year has roughly the same absolute error value, so the decline over the long term remains clear. NSIDC has high confidence in sea ice trend statistics and the comparison of sea ice extent between years."
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 03, 2017, 12:00:14 PM
So statistically indistinguishable from latest minimum on record for both JAXA and NSIDC daily because the shape of the minimum in 1986 means the minimum might have occurred on 29th Feb, 1st March or 2nd of March (3rd also possible but seems unlikely)

2.075 on daily NSIDC is new low as is 2147345 for JAXA.

By coincidence I have just asked on stupid questions what is the accuracy of these measurements. Down to 1km2 or even 1000km2 obviously spurious accuracy ?

This very valid question is at least partially addressed by the NSIDC in their FAQ section.

https://nsidc.org/arcticseaicenews/faq/#error_bars

The relevant bit reads as follows...

"We estimate error based on accepted knowledge of the sensor capabilities and analysis of the amount of “noise,” or daily variations not explained by changes in weather variables. For average relative error, or error relative to other years, the error is approximately 20,000 to 30,000 square kilometers (7,700 to 11,600 square miles), a small fraction of the total existing sea ice. For average absolute error, or the amount of ice that the sensor measures compared to actual ice on the ground, the error is approximately 50 thousand to 1 million square kilometers (19,300 to 386,100 square miles), varying over the year. During summer melt and freeze-up in the fall, the extent may be underestimated by 1 million square miles; during mid and late winter before melt starts, the error will be on the low end of the estimates. It is important to note that while the magnitude of the error varies through the year, it is consistent year to year. This gives scientists high confidence in interannual trends at a given time of year.

The absolute error values may seem high, but it is important to note that each year has roughly the same absolute error value, so the decline over the long term remains clear. NSIDC has high confidence in sea ice trend statistics and the comparison of sea ice extent between years."


So it is the trend that matters as if there is error it is consistent. It is just as well the trolls are pretty dumb. The potential for misinformation is high.


Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 03, 2017, 04:48:02 PM
Also NSIDC sees more ice:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-02 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        230.2  +12.7  -221.5        1204.5  +19.0   -44.4
                Indian Ocean           West Pacific Ocean
        106.4   -3.1   -84.2         501.5   +4.8  +127.1
                    Ross Sea                        Total
         68.4   +2.6  -752.4        2111.0  +36.1  -975.4

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        120.4   -8.3  -138.5        1002.3  +19.3   +51.1
                Indian Ocean           West Pacific Ocean
         51.7   -4.4   -43.5         293.7   -4.8   +76.3
                    Ross Sea                        Total
         23.2   +0.4  -424.6        1491.2   +2.2  -479.2
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 04, 2017, 08:55:55 AM
Not a very convincing start of the refreezing season, according to Bremen AMSR2 data:

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-03 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                229.5   -9.9                1242.8   +2.5
                Indian Ocean           West Pacific Ocean
                129.9   +0.3                 435.7  -22.4
                    Ross Sea                        Total
                 92.2  +10.5                2130.1  -19.0

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                186.1   -7.2                1120.8  +23.3
                Indian Ocean           West Pacific Ocean
                107.2   +1.2                 366.1  -17.9
                    Ross Sea                        Total
                 64.1   +5.8                1844.2   +5.3
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 04, 2017, 02:27:26 PM
NSIDC show increases, but slow compared with most other years.

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-03 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        213.1  -17.1  -244.4        1230.9  +26.4   -30.2
                Indian Ocean           West Pacific Ocean
        103.8   -2.5   -89.7         498.3   -3.1  +124.5
                    Ross Sea                        Total
         79.4  +11.0  -769.6        2125.6  +14.6 -1009.3

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        112.2   -8.2  -150.8        1017.7  +15.4   +55.9
                Indian Ocean           West Pacific Ocean
         50.2   -1.5   -45.7         284.8   -8.9   +68.0
                    Ross Sea                        Total
         26.6   +3.4  -442.2        1491.5   +0.3  -514.7
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 05, 2017, 07:19:29 AM
Small drops according to Bremen data:

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-04 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                224.7   -6.3                1241.1   -3.8
                Indian Ocean           West Pacific Ocean
                133.9   +3.3                 426.4  -11.0
                    Ross Sea                        Total
                109.8  +16.9                2135.9   -0.9

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                180.3   -6.6                1119.5   -2.9
                Indian Ocean           West Pacific Ocean
                108.9   +1.2                 359.2   -8.2
                    Ross Sea                        Total
                 72.8   +8.1                1840.7   -8.4
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 05, 2017, 02:29:57 PM
NSIDC sea ice concentration shows some small changes too:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-04 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        226.3  +13.2  -237.1        1226.6   -4.3   -43.9
                Indian Ocean           West Pacific Ocean
        103.7   -0.2   -92.3         491.2   -7.2  +112.7
                    Ross Sea                        Total
         93.0  +13.5  -784.8        2140.7  +15.1 -1045.5

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        118.3   +6.2  -148.8         997.5  -20.1   +26.5
                Indian Ocean           West Pacific Ocean
         50.9   +0.7   -45.3         286.0   +1.1   +67.7
                    Ross Sea                        Total
         33.4   +6.8  -453.8        1486.1   -5.4  -553.6



The drop in area means a new minimum. The date, 4th March, is the latest on record, shared with 2006.
Title: Re: Sea Ice Extent around Antarctica
Post by: iceman on March 05, 2017, 02:57:10 PM
NSIDC sea ice concentration shows some small changes too:
   ....
Thanks for providing details on both series during this time.  Interesting to note there are day-to-day differences by region, though the regional deltas were more in agreement on 03-01 when extent hit its minimum.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 05, 2017, 04:08:34 PM
Having the earliest top on record in August....and the latest bottom on record some time this month.....is NOT a good combo.😥I
Title: Re: Sea Ice Extent around Antarctica
Post by: Thomas Barlow on March 05, 2017, 04:19:19 PM
Was Friday a double-whammy record for the Antarctic ?
Lowest sea-ice extent on record, and also the latest autumn rebound on record.
(black line = 1991 – previous record latest rebound. )
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 05, 2017, 05:04:24 PM
One other thing to note about "bottoms" in general....both the Arctic AND Antarctic.....is that at some point.....maybe within 5 years....those bottoms will "broaden".  And they will broaden because they will BOTH start earlier AND end later.  And as we "run out of ice".....that "flat bottom" HAS to occur.

What will Joe Bastardi say then?  Inquiring minds want to know...  Poor little Joe... :o
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 05, 2017, 05:53:01 PM
Thomas Barlow: No, there was an even later rebound in 1986 when the official minimum date was March 6. The second latest rebound was March 3 back in 2003. This years minimum is very likely a tie with second latest rebound behind 1986. Since March 1 the daily gain have been almost 70K and nothing indicate that there will be any loss the next few days in the SIE around Antarctica.

The most interesting question now is how quick the refreezing will be and if we are going to see any significant polar amplification given the very long period with open waters around Antarctica which has allowed heat to penetrate down into the sea.
 
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on March 05, 2017, 06:07:47 PM
One other thing to note about "bottoms" in general....both the Arctic AND Antarctic.....is that at some point.....maybe within 5 years....those bottoms will "broaden".  And they will broaden because they will BOTH start earlier AND end later.  And as we "run out of ice".....that "flat bottom" HAS to occur.

What will Joe Bastardi say then?  Inquiring minds want to know...  Poor little Joe... :o

"NOMEN EST OMEN" (referring to bastardi LOL)
Title: Re: Sea Ice Extent around Antarctica
Post by: Thomas Barlow on March 05, 2017, 08:43:29 PM
Thomas Barlow: No, there was an even later rebound in 1986 when the official minimum date was March 6. The second latest rebound was March 3 back in 2003...The most interesting question now is how quick the refreezing will be and if we are going to see any significant polar amplification given the very long period with open waters around Antarctica which has allowed heat to penetrate down into the sea.

Ok. Good.
Thanks.
I thought we were in uncharted territory for a minute there.

Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 06, 2017, 11:10:56 AM
Small gains in the sea ice concentration data from Uni Bremen.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-05 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                230.7   +4.8                1247.9   +5.4
                Indian Ocean           West Pacific Ocean
                137.3   +2.3                 431.9   +4.1
                    Ross Sea                        Total
                121.4  +11.2                2169.3  +27.7

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                185.9   +4.7                1108.5  -11.9
                Indian Ocean           West Pacific Ocean
                109.7   +0.1                 363.8   +3.5
                    Ross Sea                        Total
                 89.0  +15.8                1856.9  +12.2
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on March 06, 2017, 12:38:17 PM
JAXA:
12232,2017,02,28,1209513600,2151409
12233,2017,03,01,1209600000,2147345
12234,2017,03,02,1209686400,2149610
12235,2017,03,03,1209772800,2159375
12236,2017,03,04,1209859200,2168927
12237,2017,03,05,1209945600,2187029

only 40k above minimum but given: how late in season, usual smoothness of SH and 4 consecutive days of gains, I think we can call the minimum was 1st March.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 06, 2017, 02:25:29 PM
Yes, NSIDC SIC says basically the same. Out of the minimum, but as long as the gains are this slow, extent stays well below the rest of the "pack".

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-05 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        220.1   -6.2  -246.2        1245.4  +18.8   -40.3
                Indian Ocean           West Pacific Ocean
        106.8   +3.1   -92.7         500.3   +9.1  +118.8
                    Ross Sea                        Total
         87.1   -5.9  -810.6        2159.7  +18.9 -1071.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        128.7  +10.3  -139.4        1004.8   +7.3   +21.9
                Indian Ocean           West Pacific Ocean
         53.8   +2.9   -42.4         297.2  +11.2   +77.3
                    Ross Sea                        Total
         32.8   -0.6  -470.4        1517.4  +31.2  -552.9


Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 07, 2017, 01:32:06 AM
Here are two "cut-down" versions of NSIDC's rolling 5-day Charctic for the Antarctic sea ice extent with data up to the 5th March. The first concentrates on the next 5 or 6 weeks, whilst the second looks at the period from late May until mid November. (By which time, 2016 had already firmly moved into "lowest value for the date".)

There's a few things that one can pull out (starting with the first attachment)...

1) After its "moment in the sun", 1997 (dark green) starts to fade into the pack. (And stays near the median for the rest of the year.)

2) 1993 (orange) has "lowest ever value for the date" until the 11th of March. However, over the following two weeks, it grows with extreme rapidity until it gets very close to the median value. (And stays around the median for the remainder of the year.)

3) Although 2016 (reddish) initially rises rapidly, such that it exceeds the median by around the 22nd March, it subsequently drops pretty low from mid-September onward. (That means there is a distinct possibility that the rolling annual average will plummet over the next few months.)

4) 2006 (purplish) has "lowest ever value for the date" between the 12th and 23rd of March, but ends up being outside the highest interdecile range by mid-August.

5) 1980 (yellow) then has the "lowest ever value for the date" until almost the end of May.

6) Looking at the second chart (end of May until mid November), for most of this period, 1980 continues to share "bottom billing", along with 1986 and 2002. (A few years briefly interrupt this three-way hegemony, but there's little to be gained by adding the additional "clutter".) However, by November 5th, 2016 moves into uncharted territory.
(Which is where we've been ever since.)
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 07, 2017, 08:06:39 AM
Not much freezing in the Uni Bremen AMSR2 sea ice concentration.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-06 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                238.8   +7.3                1242.7   -7.2
                Indian Ocean           West Pacific Ocean
                139.7   +1.3                 442.0   +8.6
                    Ross Sea                        Total
                111.0  -11.3                2174.3   -1.4

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                191.3   +4.8                1088.9  -21.2
                Indian Ocean           West Pacific Ocean
                109.1   -1.5                 364.6   -0.5
                    Ross Sea                        Total
                 79.2  -10.4                1833.0  -28.7
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 07, 2017, 01:59:45 PM
NSIDC agrees.

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-06 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        231.0  +10.8  -239.1        1249.9   +4.5   -49.3
                Indian Ocean           West Pacific Ocean
        102.5   -4.3   -95.3         504.6   +4.3  +118.1
                    Ross Sea                        Total
         74.8  -12.3  -844.1        2162.7   +3.1 -1109.7

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        118.4  -10.2  -150.6        1019.1  +14.2   +29.4
                Indian Ocean           West Pacific Ocean
         53.3   -0.6   -43.3         295.3   -1.9   +72.3
                    Ross Sea                        Total
         28.5   -4.4  -491.4        1514.6   -2.8  -583.5
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on March 07, 2017, 10:28:15 PM
JAXA, on the other hand, has started moving up more rapidly:

(https://i.gyazo.com/9139f5925da9462af4e5cdf321cd989f.png)
Title: Re: Sea Ice Extent around Antarctica
Post by: DrTskoul on March 07, 2017, 10:44:57 PM
 :o :o
Tremendous
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 08, 2017, 08:18:00 AM
A small drop in extent according to Bremen AMSR2 sea ice concentration.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-07 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                238.4   -1.5                1276.3  +31.2
                Indian Ocean           West Pacific Ocean
                134.6   -6.5                 420.6  -23.1
                    Ross Sea                        Total
                104.4   -7.4                2174.3   -7.2

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                192.5   +0.6                1126.5  +35.6
                Indian Ocean           West Pacific Ocean
                105.5   -4.6                 360.0   -6.0
                    Ross Sea                        Total
                 72.4   -7.3                1857.0  +18.3
Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on March 08, 2017, 09:16:21 AM
What is JAXA seeing? They record a 47,514 km2 increase for yesterday.

2017-03-07: 2245025
2017-03-06: 2197511
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 08, 2017, 03:30:44 PM
Refreezing according to NSIDC sea ice concentration was slow in the latest data.

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-07 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        207.0  -24.0  -274.0        1292.4  +42.5   -13.0
                Indian Ocean           West Pacific Ocean
        112.2   +9.7   -91.3         471.1  -33.5   +76.4
                    Ross Sea                        Total
         82.6   +7.8  -864.0        2165.3   +2.5 -1166.0

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        100.9  -17.6  -172.9        1051.5  +32.4   +56.4
                Indian Ocean           West Pacific Ocean
         56.8   +3.5   -42.7         278.7  -16.6   +51.2
                    Ross Sea                        Total
         32.8   +4.3  -510.4        1520.5   +6.0  -618.5
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 09, 2017, 07:17:18 AM
Bremen AMSR2 sea ice concentration shows solid increases for the first time.

Regional Antarctic Sea Ice Extent and Area calculated from Uni Bremen ASI AMSR2 concentration data
See ub_am2_3.125_ant.txt for more details
Date: 2017-03-08 12:00  Values in 1000 km^2

Extent (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                242.1   +2.2                1338.6  +61.1
                Indian Ocean           West Pacific Ocean
                137.7   +2.2                 446.5  +23.8
                    Ross Sea                        Total
                106.3   +1.1                2271.2  +90.5

Area (value, one day change):
Bellingshausen&Amundsen Seas                   Weddel Sea
                194.8   +1.5                1201.5  +74.2
                Indian Ocean           West Pacific Ocean
                107.2   +1.2                 371.4   +9.7
                    Ross Sea                        Total
                 70.8   -2.2                1945.8  +84.3
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 09, 2017, 08:14:27 AM
Your numbers confirmed my analyze after eyeballing todays SIE map, Wipneus. Weddell Sea is showing significant visible refreezing on the map. This should continue over the next couple of days as the forecast calls for continously cold or very cold weather in the southeast part of Weddell Sea. Overall, cold weather is foreseen to dominate over the next 5 days over most of Antarctica. The exception is the area from Ross Sea to Bellingshausen Sea where warmer than normal temperatures will prevail which should limit the ice growth there. Once these warm anomalies will be replaced by cold air from the interior of Antarctica we should see a rapid or very rapid ice growth.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on March 09, 2017, 08:24:42 AM
Anyway the ice-free Ross sea is a bad thing for the freezing season. It's usually one of the first area to start to refreeze and to export it's ice pack further. No ice yet, low albedo, extra heat have been (and still) accumulated, MYI has gone, there are no ice to be exported
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 09, 2017, 01:58:14 PM
And NSIDC more or less confirms:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-08 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        211.6   +4.6  -277.8        1308.9  +16.5    -4.5
                Indian Ocean           West Pacific Ocean
        114.7   +2.5   -98.5         514.7  +43.6  +109.9
                    Ross Sea                        Total
        104.1  +21.5  -871.9        2253.9  +88.7 -1142.8

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        104.4   +3.6  -174.4        1078.7  +27.2   +77.3
                Indian Ocean           West Pacific Ocean
         58.5   +1.7   -44.6         302.9  +24.2   +70.1
                    Ross Sea                        Total
         38.3   +5.6  -529.5        1582.8  +62.2  -601.2
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 13, 2017, 02:53:31 PM
Refreezing somewhat slower than last year. Jaxa extent measurement now over 1 million km2 less than 2016. SST anomalies still high north of antarctic circle but air temps below average. Early days but worth watching refreezing season.
Title: Re: Sea Ice Extent around Antarctica
Post by: bairgon on March 13, 2017, 03:08:35 PM
4 days out on Nullschool - 17th March - there is a fairly strong and warm northerly blowing on the Weddell Sea. This lasts for about a day and might cause some compaction of the spreading ice at the periphery, lowering the area.

https://earth.nullschool.net/#2017/03/17/2100Z/wind/surface/level/overlay=temp/orthographic=-6.32,-83.08,1203/loc=-53.832,-63.919 (https://earth.nullschool.net/#2017/03/17/2100Z/wind/surface/level/overlay=temp/orthographic=-6.32,-83.08,1203/loc=-53.832,-63.919)
Title: Re: Sea Ice Extent around Antarctica
Post by: AbruptSLR on March 14, 2017, 06:09:46 PM
The linked reference discusses the tempo of changes in the hemispheric differences in sea ice distribution under different paleo radiative forcing conditions:

Jung-Eun Lee, Aaron Shen, Baylor Fox-Kemper & Yi Ming (27 January 2017), "Hemispheric sea ice distribution sets the glacial tempo", Geophysical Research Letters, DOI: 10.1002/2016GL071307

http://onlinelibrary.wiley.com/doi/10.1002/2016GL071307/full (http://onlinelibrary.wiley.com/doi/10.1002/2016GL071307/full)

Abstract: "The proxy record of global temperature shows that the dominant periodicity of the glacial cycle shifts from 40 kyr (obliquity) to 100 kyr (eccentricity) about a million years ago. Using climate model simulations, here we show that the pace of the glacial cycle depends on the pattern of hemispheric sea ice growth. In a cold climate the sea ice grows asymmetrically between two hemispheres under changes to Earth's orbital precession, because sea ice growth potential outside of the Arctic Circle is limited. This difference in hemispheric sea ice growth leads to an asymmetry in absorbed solar energy for the two hemispheres, particularly when eccentricity is high, even if the annual average insolation is similar. In a warmer climate, the hemispheric asymmetry of the sea ice decreases as mean Arctic and Antarctic sea ice decreases, diminishing the precession and eccentricity signals and explaining the dominant obliquity signal (40 kyr) before the mid-Pleistocene transition."
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 14, 2017, 07:22:29 PM
The linked reference discusses the tempo of changes in the hemispheric differences in sea ice distribution under different paleo radiative forcing conditions:
...
Abstract: "The proxy record of global temperature shows that the dominant periodicity of the glacial cycle shifts from 40 kyr (obliquity) to 100 kyr (eccentricity) about a million years ago.
...

When I read the above, it sounded vaguely familiar. (Everything is vague to me these days :()

The wiki entry on the Quaternary Glaciation contains the following text...
"... During the Quaternary Period, the total volume of land ice, sea level, and global temperature has fluctuated initially on 41,000- and more recently on 100,000-year time scales, as evidenced most clearly by ice cores for the past 800,000 years and marine sediment cores for the earlier period ..."

https://en.wikipedia.org/wiki/Quaternary_glaciation

Nice to see some agreement.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 14, 2017, 08:22:06 PM
Here's what things look like using ADS/Vishop (ver 2).

As usual, it's zoomed and filtered so that just the relevant low-ball years are displayed.

One thing perhaps worth noting is the gap between the extent on 13th March this year and that recorded last year - currently sitting at around -1.1 million sq kms. It doesn't take an Einstein to realise that, as long as the gap stays roughly similar, the rolling 365-day average will drop by ~ 3k sq kms each day.

The current (13 Mar 2017) rolling 365-day average using the ADS data stands at ~11.002 million sq kms, and should therefore drop below 11 million tomorrow.

There are some data drops which require infill and the measurement periodicity alters, but, if my technique was at all reasonable [  :-\ ] the previous low for this metric was 11.090 million sq kms. This was clocked up around early August 1980.

NB Using the NSIDC figures for Antarctic extent, the current rolling 365-day value is ~11.027 million sq kms, still some way above the equivalent value of 10.969 million sq kms recorded for early August 1980. Should the gap between this year and last year remain much the same, it will take about ~ 20 days to reach this record low value.

Title: Re: Sea Ice Extent around Antarctica
Post by: bairgon on March 17, 2017, 07:12:22 AM
From the Arctic 2017 melting season thread:

Antarctic Sea Ice is doing what the Arctic sea ice did this last fall and winter.

https://seaice.uni-bremen.de/data/amsr2/today/extent_s_running_mean_amsr2_regular.png

Those northerly winds are starting to blow on Weddell:

17th March - there is a fairly strong and warm northerly blowing on the Weddell Sea.

Wipneus, any chance of daily updates on area for each region again?
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 17, 2017, 08:50:40 AM

Wipneus, any chance of daily updates on area for each region again?

At the moment I am not calculating Uni Bremen automatically. The Uni Hamburg data are virtually the same ( same satellite measurements, same algorithm).

Antarctic Uni Hamburg data is here:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/uh_am2_ant.txt

Antarctic regional graphs are here:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/uh-amsr2-ant-area-overview.png
and:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/uh-amsr2-ant-extent-overview.png

Antarctic NSIDC data and graphs are here:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_main.txt
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_detail.txt
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-ant-nt-area-overview.png
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-ant-nt-extent-overview.png
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 17, 2017, 10:05:20 AM
A small observation:-
On March 16 2017 jaxa measurement says antarctic sea ice 1/3 rd less than on March 16 2017. Difference currently increasing every day.
Title: Re: Sea Ice Extent around Antarctica
Post by: bairgon on March 17, 2017, 11:14:23 AM
Antarctic Uni Hamburg data is here:

Thanks for the links. I had browsed the start page and site map for your site but couldn't find links to this data.

It appears that the Ross sea, and to a lesser extent the Weddel sea are the main reason for the slow growth.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 17, 2017, 02:30:51 PM
A small observation:-
On March 16 2017 jaxa measurement says antarctic sea ice 1/3 rd less than on March 16 2017. Difference currently increasing every day.


A)  Good observation
B)  That is HUGE....not small. ;)

Title: Re: Sea Ice Extent around Antarctica
Post by: be cause on March 17, 2017, 03:31:20 PM
perhaps those should be 2 different dates ? .. gerontocrat / Buddy ? Perhaps 2014 was the comparison ?

Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 17, 2017, 03:51:01 PM
perhaps those should be 2 different dates ? .. gerontocrat / Buddy ? Perhaps 2014 was the comparison ?

1)  I think he meant 2016 (last year).  Sloppy of ME not to catch that. Good catch by you. ;D

2)  Difference is actually 30% (but 30% vs 33% is immaterial).

What I was READING was 2017 compared to 2016.  And a 30% or 33% difference is a BIG DEAL.  I "believe" that is what he meant...

2.56 = 2017
3.68 = 2016
1.12 = Difference....which is 30% less than 2016....





Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 17, 2017, 05:08:28 PM
A small observation:-
On March 16 2017 jaxa measurement says antarctic sea ice 1/3 rd less than on March 16 2017 [2016]. Difference currently increasing every day.

If you look further up the page at #559, point No 3, you'll get a foretaste of how that might progress...

"3) Although 2016 (reddish) initially rises rapidly, such that it exceeds the median by around the 22nd March, it subsequently drops pretty low from mid-September onward. (That means there is a distinct possibility that the rolling annual average will plummet over the next few months.)"

Although that related to NSIDC figures, the IJIS/JAXA/ADS numbers are pretty similar. By the 24th March, the 2016 figures had already reached and exceeded all of the 3 decadal averages.

There is a bit more on the IJIS/JAXA/ADS numbers at #575.

Given the extreme variability demonstrated by the Antarctic in the past, I'm still adopting a "wait and see" viewpoint.

Meanwhile, in a place quite literally poles apart from the Arctic, things are moving in the opposite direction - in every sense...
...
I think it's too early to say if this is purely down to specific weather conditions, or whether the sea ice in the Antarctic is starting to respond to climate change in an analogous fashion to its boreal cousin. However, a watching brief is definitely in order.

However, there is some evidence to suggest that a switch in the Interdecadal Pacific Oscillation has kicked in. See here...

https://www.carbonbrief.org/pacific-ocean-behind-recent-antarctic-sea-ice-growth-study-says (https://www.carbonbrief.org/pacific-ocean-behind-recent-antarctic-sea-ice-growth-study-says)
Title: Re: Sea Ice Extent around Antarctica
Post by: dnmun on March 17, 2017, 06:49:14 PM
can someone cut and paste that article? my browser will not open it because it considers the server insecure.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 17, 2017, 06:57:47 PM
I suggest that you read what NSIDC has in their FAQ about Antarctica: http://nsidc.org/arcticseaicenews/faq/#wintertimeantarctic (http://nsidc.org/arcticseaicenews/faq/#wintertimeantarctic)

I think their explanation fits fairly well to explain the exceptionally low SIE we have seen this season, and I agree with Bill, we have to wait and see what happens in the coming years given the very large yearly variability.

Title: Re: Sea Ice Extent around Antarctica
Post by: oren on March 17, 2017, 10:48:55 PM
...we have to wait and see what happens in the coming years given the very large yearly variability.
And given Hansen's feedback of melting glaciers resulting in increased sea ice around Antarctica. Should the WAIS mass loss continue to accelerate, there will be a large input of fresh cold water into the southern ocean. Very different from the Arctic, continent in the middle vs. ocean in the middle.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 18, 2017, 12:24:13 AM
Should the WAIS mass loss continue to accelerate, there will be a large input of fresh cold water into the southern ocean. Very different from the Arctic, continent in the middle vs. ocean in the middle.

Yes. We also have increased strength of Westerlies resulting in increased Coriolis deflection, which obviously causes spreading in an equator-ward direction. In addition to that, the good old Clausius-Clapeyron relationship means that, thanks to the warming South Pacific, there will be a higher atmospheric moisture content, which in turn will lead to enhanced precipitation (snow and rain); both of these forms contribute to a temporary increase in sea ice area/extent.

... we have to wait and see what happens in the coming years given the very large yearly variability.

Possibly the best example I can think of to back up that statement comes from the NSIDC monthly figures for Antarctic sea ice area. The year 2006 still has the lowest value for March in that dataset - at least for the next few weeks. However, by August, it had grown to 2nd highest - although that month has since been equalled once, and beaten 3 times. September 2006 was actually, although briefly, the highest for that month, and has been surpassed on 4 occasions. October 2006 also had the "highest for that month" status, but now trails in the wake of 2013 & 2014.

Bizarrely, by December, 2006 had moved to 8th lowest area, and has only slipped one place since then.

That is why neither LMV or myself are getting carried away at the moment by developments down there.
Title: Re: Sea Ice Extent around Antarctica
Post by: georged on March 18, 2017, 07:44:49 AM
And NSIDC more or less confirms:

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-08 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        211.6   +4.6  -277.8        1308.9  +16.5    -4.5
                Indian Ocean           West Pacific Ocean
        114.7   +2.5   -98.5         514.7  +43.6  +109.9
                    Ross Sea                        Total
        104.1  +21.5  -871.9        2253.9  +88.7 -1142.8

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        104.4   +3.6  -174.4        1078.7  +27.2   +77.3
                Indian Ocean           West Pacific Ocean
         58.5   +1.7   -44.6         302.9  +24.2   +70.1
                    Ross Sea                        Total
         38.3   +5.6  -529.5        1582.8  +62.2  -601.2


Thanks for these updates during the season.

Does anyone have the 2017 NSIDC/JAXA final lows (area, extent) and their comparison to the top ten previous years?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 18, 2017, 01:41:45 PM
Hullo Georged,

The only data I have is Jaxa's .CSV files on daily measures of Arctic and Antarctic sea ice extent. They are easily downloaded - I use Jaxa's version 1 as I find it easier to use for the very simple things I do (environmental arithmetic as opposed to real maths). The address is https://ads.nipr.ac.jp/vishop.ver1/vishop-extent.html?N

So I simply observe that Antarctic sea ice has been several standard deviations below the average in the satellite record  for some time. Methinks I was taught by my statistics tutor that the greater that deviation then the less likely it is that the observations were random chance. Which is why I still think keeping an eye on what's going on down south is of value.

But what were the causes of such massive variations from the "norm" ?
And what has been the effect on sea ice shelves exposed to open ocean in a way they have not been for a good many years?

And isn't it strange that we find that we know least about that which we find we need to know most? (Antarctica, the Oceans)
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 18, 2017, 06:42:49 PM
Today the 2017 NSIDC Antarctic area becomes lowest for the day.  1993 that was lowest at minimum by a wide margin is now #nine or so.

extent SH
1986-03-17 3.720040
1985-03-17 3.665129
1984-03-17 3.632114
2011-03-17 3.498813
1992-03-17 3.449271
1997-03-17 3.399628
1981-03-17 3.374994
1980-03-17 3.312352
2006-03-17 3.085380
2017-03-17 2.663219
area SH
1992-03-17 2.359388
1993-03-17 2.357730
1986-03-17 2.322920
1984-03-17 2.318267
2011-03-17 2.286173
1997-03-17 2.212859
1981-03-17 2.149549
1980-03-17 2.143683
2006-03-17 1.867773
2017-03-17 1.817864


Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 18, 2017, 09:50:36 PM
The most interesting thing right now is how much impact the sun have had on the SSTs around the continent given the exceptionally low levels of SIE that have prevailed since the middle of November last year. The SIE maximum around Antarctica should most likely be quite normal by late summer/early fall but we might have a long period with SIE much below average.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on March 19, 2017, 06:44:41 PM
The most interesting thing right now is how much impact the sun have had on the SSTs around the continent given the exceptionally low levels of SIE that have prevailed since the middle of November last year. The SIE maximum around Antarctica should most likely be quite normal by late summer/early fall but we might have a long period with SIE much below average.

since antarctica is not surrounded by land i predict that in the not so far future the austral winter numbers in antarctic sea-ice extent will drop significantly while in the arctic it will take some more time until the basin won't be more or less filled with ice.

last but not least land and ice-masses together keep that part cold in winter while warmer oceans will have their inmpact in the south rather directly.

this is not meant to happen under all circumstances already now (but it could) while i'm quite sure that the described scenario is not too far ahead if at all :-)
Title: Re: Sea Ice Extent around Antarctica
Post by: DavidR on March 21, 2017, 09:45:37 PM
The most interesting thing right now is how much impact the sun have had on the SSTs around the continent given the exceptionally low levels of SIE that have prevailed since the middle of November last year. The SIE maximum around Antarctica should most likely be quite normal by late summer/early fall but we might have a long period with SIE much below average.
Sea temperatures from 60S -> 75S have been much warmer over the past two months than during the past decade. I expect this to continue to inhibit SIE growth leading to a near record low maximum this year.  My  early  prediction is that all four significant records for extent will fall this year, both the maximums and minimums for Arctic and Antarctic. This would be an effect of the significant rise in SSTs accompanying the recent El Nino
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 23, 2017, 12:24:22 PM
The re-freezing of Antarctica continues to impress by its slow pace. The current (March 22 Jaxa) measurement of extent of 3,038,106 sq km is now 1.3 million km2 less than the 1980s average (1980s being the lowest decade). This is an increased difference of 0.4 million compared with 20 days ago (the 2017 minimum).
As DavidR pointed out, SST anomalies as far north as 60 S currently point to this continuing (caveat: all other things being equal). So on a risk analysis approach given the available data, I can see no reason for this year's maximum not to be very low (even though the variability from year to year in Antarctica is extreme, meaning all predictions have a low probability of accuracy ?).

But, given the accumulated expertise gathered within ASIF, what do I know ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 23, 2017, 03:13:11 PM
The re-freezing of Antarctica continues to impress by its slow pace.

Not surprising.  It is.....of course.....hard to discern "intermediate trends" from "short term trends"....but the long term trend is certainly in place.  Right now.....warmish waters around Antarctica, especially in the Pacific.

 
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 23, 2017, 05:08:22 PM
Wipneus: NSIDC reported a 39K DROP in SIE for March 22. Do you, or anyone else here, know whether this is unheard of or at least unusual?

Which area contributed to the small decline?

//LMV
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 23, 2017, 06:37:54 PM
Wipneus: NSIDC reported a 39K DROP in SIE for March 22. Do you, or anyone else here, know whether this is unheard of or at least unusual?

I think drops in (NSIDC) Antarctic extent during March have been recorded on 58 occasions. The arithmetic average of these drops is -28k, and the largest was -169k way back in 1979.

Between the 10th and 31st March, there have only been drops on 22 occasions.

Between them, April and May have seen 25 such drops. These averaged -22k, with the largest, -79k, happening in May 1986.

HOWEVER, those numbers need to be qualified by the fact that daily recording didn't start until September 1987. Therefore, those two "big" drops were actually two-day drops. On the other hand, the total number of days showing a drop would likely be somewhat higher.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on March 23, 2017, 06:53:59 PM
Wipneus: NSIDC reported a 39K DROP in SIE for March 22. Do you, or anyone else here, know whether this is unheard of or at least unusual?

Which area contributed to the small decline?

//LMV

Regional Antarctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-03-22 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
        192.1   -2.5  -402.2        1550.5   -7.6   -49.4
                Indian Ocean           West Pacific Ocean
        192.4  -14.7  -138.4         593.3  -33.9   +72.0
                    Ross Sea                        Total
        415.3  +19.7 -1010.6        2943.6  -38.9 -1528.6

Area (value, one day change, anomaly):
Bellingshausen&Amundsen Seas                   Weddel Sea
         99.1   +0.7  -253.8        1155.8  -21.8   -73.2
                Indian Ocean           West Pacific Ocean
         78.0   -2.6   -95.1         355.0   -7.7   +54.1
                    Ross Sea                        Total
        208.6  +14.3  -762.5        1896.6  -17.1 -1130.7


This is actually the contents of:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_nrt_summary.txt

This is auto-updated daily.

If you need the regional data for other dates than the last the look here:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_detail.txt

Auto-updated as well.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 24, 2017, 02:00:17 PM
I am probably EQUALLY interested to see what the Antarctic MAXIMUM will be this coming August/Sept.....as I am to see what this September's Arctic MINIMUM will be.

The slowly warming oceans are clearly having an effect on both.  Another Antarctic record low MAXIMUM would be a very bad message indeed.  And if we head into another El Nino later this year...that would certainly not be good news.

I continue to watch Wip's total sea ice area map with intense interest.  Basic physics at work I'm afraid.



Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 28, 2017, 02:35:02 PM
Jaxa measurement of extent 27th March 2017 is 3,329,871 km2. This is 663,237 km2 (circa 17 %) less than the previous lowest figure for this date in 2006, and 37% below the average for this date in the 1980s. Antarctic sea ice extent has now been at or below previous record minimums for around 5 months. Current refreezing rates are below the average.

Anyone out there got ideas on what has changed since the record maximum in 2014 and whether one can speculate on a possible long-term sea change in the Antarctic ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 28, 2017, 02:53:47 PM
This is 663,237 km2 (circa 17 %) less than the previous lowest figure for this date in 2006,

A)  17% BELOW the prior record is A BUNCH.

B)  Do you know what the % drop is from LAST YEAR at this time?  I assume slightly more than 17%....but would be curious to know if you have that figure....thanks.



Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 28, 2017, 03:49:30 PM
This is 663,237 km2 (circa 17 %) less than the previous lowest figure for this date in 2006,

A)  17% BELOW the prior record is A BUNCH.

B)  Do you know what the % drop is from LAST YEAR at this time?  I assume slightly more than 17%....but would be curious to know if you have that figure....thanks.

I knew I should have double-checked. The 37 % drop is compared with 2016. (The drop compared with the 1980s (the decade with the lowest extent) is a mere 29 percent). The drop compared with 27 March 2015 is 44 percent. The change in the last two years has been lunatic. Mais pourquoi ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 28, 2017, 04:17:24 PM
Mais pourquoi ?

Yes....why indeed.  As I noted in my "rant" with the two graphs.....it could be several things combined.  All I know....is the facts that I see.

And 17% below the all time record is a LOT......and a 37% drop compared to last year is off the charts.  As a NON SCIENTIST....but an analyzer of facts and figures....I would first look at the OCEAN (continually increased warming) AND any change in currents as I noted before.  Certainly....my untrained scientific eye would look at the El Nino and its after effects as well.

The thing with global warming....is there are SO MANY THINGS THAT ARE CONSTANTLY CHANGING.....that it must be a real devil to ferret out what the current causes are....because ALL the causes/changes effect each other to some extent.

Thanks for getting that number by the way....
Title: Re: Sea Ice Extent around Antarctica
Post by: oren on March 28, 2017, 05:01:16 PM
The main difference from previoues years is the Ross Sea. Other seas are within the historic variance, though on the low side. Not sure what happened there, I used to think it was some Pacific teleconnection from the monster El-Nino, not sure anymore. If next year repeats the same performance in Ross, it will be even more interesting.
Title: Re: Sea Ice Extent around Antarctica
Post by: crandles on March 28, 2017, 05:16:23 PM
Currently 3.33 vs 3.99 for 2006 & 2011 16.5% down 0.66 m km2 down

6 March 2017 2.2 vs 2.68 for 2006 18% down 0.48 m km2 down

15 Dec 2016 8.05 vs 9.46 for 2005 15% down 1.41 m km2 down

16.5% down on record low is not quite a record amount in % terms, as reached 18% down on previous record in early March. (Still the km2 is larger now.)

But in m km2 current 0.66 is small compared to December which reached 1.41 down.

Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on March 28, 2017, 06:37:42 PM
I suggest that you read this section of NSIDC faq where they highlight an scientific study (Meehl, 2016) which claims that the switch in the PDO/IPO and El Niño as a possible reason for the changes we have seen so far.

http://nsidc.org/arcticseaicenews/faq/#wintertimeantarctic (http://nsidc.org/arcticseaicenews/faq/#wintertimeantarctic)
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 29, 2017, 12:05:37 PM
As the ASIF was down for some time, I originally posted the following comments on the current ASIB thread instead.

Every day since the 5th November 2016, Antarctic sea ice extent has been at record low levels. The NSIDC daily Antarctic sea ice extent value for March 27th came in at 3.304 million sq kms. This was a somewhat jaw-dropping 2.037 million sq kms lower than the equivalent figure from last year.

The cumulative effect of just over 20 weeks at record low levels has obviously been dragging down the rolling 365-day annual average extent figure. In fact, for the last 5 days, this average extent value has been dropping at over 5k sq kms each day.

The latest (as at 27th March) rolling 365-day average extent value has now dropped to 10.966 million sq kms. The previous record low average was 10.969 million sq kms (6th Aug 1979 - 4th Aug 1980).

To give a bit more perspective, decadal averages (calculated from the NSIDC monthly values) come out as...

1980-89 11.82 million sq kms
1990-99 12.03 million sq kms
2000-09 12.18 million sq kms
2010-16 12.46 million sq kms

Several weeks ago, on the relevant ASIF thread, I had been demonstrably cautious when I had suggested that the rolling 365-day figure would drop below 11 million sq kms by the end of March, and could likely surpass the previous record low sometime toward the end of April.

CAVEAT: Prior to the 20th Aug 1987, figures were produced on alternate days. Therefore, during that earlier record low period (1979-1980), the rolling 365-day figure actually comprised just 183 data points. The implicit assumption is, of course, that the "missing" days will, on average, tend to be halfway between the before/after dates. Some will be lower, some will be higher, but this should just about even out over the 182 "missing" days.


As LMV has just pointed out yet again (see also his comment #585, and my #583 and #587) there are good scientific reasons behind this latest twist in the Antarctic sea ice saga.

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 29, 2017, 12:23:25 PM
Archaeologists, when they are on a dig, say one needs three bricks before one can say for definite one has found a wall. When I look at the collapse in antarctic sea ice over the last 2 1/2 years, I think I only see one brick, as variability of extent is so high in the satellite record.

Perhaps one needs another two years of consistently extremely low sea ice extent before asking if  natural variation is being supplemented by AGW having penetrated the wall of Antarctic's isolation.

Meanwhile, did the extremely low sea ice this year allow significant impacts on any of the ice shelves ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on March 29, 2017, 12:36:27 PM
When I look at the collapse in antarctic sea ice over the last 2 1/2 years, I think I only see one brick, as variability of extent is so high in the satellite record.

That 2 and 1/2 year period may only be "one brick"......but it happens to be about the 30th brick, not the first if you're looking long term.  If you're looking intermediate term (from 2007)....then it is about the 3rd or 4th brick.

IF you are JUST talking about the Antarctic sea ice level.....without looking at the Arctic or looking at the other "things" related in a BROADER SENSE....then I can understand what you are trying to say.  BUT....putting in a context of what is happening in Arctic, Greenland, feedback effects, etc....THAT is why I would "broaden" the context.

And....it certainly makes the current 12 month period extremely interesting regarding the Antarctic...because IF this year also ends up like the past year....it will certainly heighten the concern of most everyone.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 29, 2017, 01:24:22 PM
... When I look at the collapse in antarctic sea ice over the last 2 1/2 years ...
It's not even as long as that. NSIDC's 5-day Charctic feature tells us that , as recently as July 12th 2015, Antarctic extent was at a record high for the date. The average extents for March 2016 and April 2016 currently rank 24th and 25th lowest (out of 38) respectively. {Soon to become 25th and 26th respectively out of 39.}

As every month from July 2012 to July 2015 (inclusive) had an average extent which was in the highest quartile, we most assuredly need more data in order to see if the behaviour over the last 7 months will prove to be a genuine "state change", or whether it is nothing more than a chimera - albeit an interesting one.

Your concern over the impact on the shelves is shared. I am looking forward (although with some trepidation) to flow-rate data from the British Antarctic Survey regarding places such as Thwaites and P.I.G.

LMV has, on more than one occasion, provided a link to the NSIDC's FAQ which deals with Antarctic variability, and it is well worth the read.
http://nsidc.org/arcticseaicenews/faq/#wintertimeantarctic (http://nsidc.org/arcticseaicenews/faq/#wintertimeantarctic)
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 29, 2017, 01:56:36 PM
NSIDC has just published the data for 28th March.

The daily value jumped a less-than-impressive 53k sq kms to 3.357 million sq kms. This is now 2.082 million sq kms less than this time last year.

The rolling 365-day dropped 5.7k sq kms to 10.96 million sq kms. On the 30th April 2016, this particular metric stood almost exactly one million sq kms higher at 11.96 million sq kms. Since the 28th Feb 2017, it has dropped almost exactly 100k sq kms.

NSIDC should publish their monthly figures by about the 2nd April, and I will be paying particular attention to area, as that looks even worse.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on March 31, 2017, 01:58:31 PM
Dear Bill, (shades of Private Eye from the Thatcher years ?)

Thanks for reminder to look at NSIDC's comments on Antarctic sea ice extent. They aren't really sure themselves, are they ? Looked at the PDO history and compared the index with various lows (1980, 2006) and highs 2014-2015, and couldn't see much correlation. (Mind you, too damn lazy to plug in the two sets of data and let excel do the math). So I remain adrift, unable to even have an opinion to be shot down (or Dinged?).

So nowt to do but wait and see. Will antarctic sea ice persist in staying at a record low, or will the wiggly line drift back into the ruck. (Note that 2006 no longer the lowest - it is 1980 that is the outlier until the end of May).

Sometimes watching slow-motion train wrecks is a real drag.

Charctic on NSIDC says that the 28th March extent was 3.205 m km2, the 29th 3.278 m km2 and the 30th 3,353 m km2. i.e. increase of circa 75,000 km2 per day, still a bit below the average daily increase for the time of year.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on March 31, 2017, 08:16:30 PM
Thanks for reminder to look at NSIDC's comments on Antarctic sea ice extent.

I've just re-read my #610 and it might appear that I was aiming that reminder specifically at you. Apologies if that's how it seemed. It was meant as a sort of general throw-away line, and I should have made this more clear.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on April 03, 2017, 04:23:36 PM
Jaxa extent for 2nd April is 3,784,646 km2, still 1.4 million km2 below the 1980's average.

The wiggly line continues to boldly go where no wiggly line has been before.
Or,
literally in uncharted territory.


Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on April 06, 2017, 11:36:11 AM
Jaxa extent for 2nd April is 3,784,646 km2, still 1.4 million km2 below the 1980's average.

The wiggly line continues to boldly go where no wiggly line has been before.
Or,
literally in uncharted territory.

Whereupon in just 3 days sea ice extent increases by 440,300 km2 to 4,224,946 km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: RikW on April 06, 2017, 12:07:45 PM
that's not extremely much, on average it should increase with around 9 million m2 between mid march and mid june, so on average 100k/day, with the increase a little higher on the first half compared to the 2nd half
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on April 11, 2017, 04:37:32 PM
Archaeologists, when they are on a dig, say one needs three bricks before one can say for definite one has found a wall. When I look at the collapse in antarctic sea ice over the last 2 1/2 years, I think I only see one brick, as variability of extent is so high in the satellite record.

Perhaps one needs another two years of consistently extremely low sea ice extent before asking if  natural variation is being supplemented by AGW having penetrated the wall of Antarctic's isolation.

Meanwhile, did the extremely low sea ice this year allow significant impacts on any of the ice shelves ?

Were we not expecting a change in Sea ice cover around Antarctica then we might say that but we know the Ozone forcing is now on the wane , year on year, and the Pacific naturals flipped to support a 'less ice' set up back in 2014.

I agree we need more bricks but geophysical says there's a wall there so do not be surprised when one turns up and we see 30 years of 'catchup' going on as Shelfs respond to higher energy summers with open water providing much more 'waggle factor' to the floating extensions!
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on April 11, 2017, 07:25:09 PM
The SIE around Antarctica have increased significantly during the last week or so and is now more or less equal with 1980. It seems reasonable to believe that 2017 won't be lowest on record in a few days or so as the spatial distribution of the se differs quite a lot between 1980 and 2017.
Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on April 12, 2017, 01:12:15 PM
The SIE around Antarctica have increased significantly during the last week or so and is now more or less equal with 1980. It seems reasonable to believe that 2017 won't be lowest on record in a few days or so as the spatial distribution of the se differs quite a lot between 1980 and 2017.
I'm curious as to whether that indicates ongoing basal melt and the spread of easy to freeze fresh water and if that's the case what implications it has for future ice loss.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on April 12, 2017, 06:57:48 PM
The SIE around Antarctica have increased significantly during the last week or so and is now more or less equal with 1980. It seems reasonable to believe that 2017 won't be lowest on record in a few days or so ...


And, as if by magic...


Title: Re: Sea Ice Extent around Antarctica
Post by: nicibiene on April 13, 2017, 09:29:34 AM
I'm curious as to whether that indicates ongoing basal melt and the spread of easy to freeze fresh water and if that's the case what implications it has for future ice loss.

I assume it could be caused by more meltwater available. Just wanted to check the massloss and wonder again why some official available datas quit at a certain point... here datas from https://data1.geo.tu-dresden.de/ais_gmb/

Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on April 13, 2017, 10:35:22 AM
The SIE around Antarctica have increased significantly during the last week or so and is now more or less equal with 1980. It seems reasonable to believe that 2017 won't be lowest on record in a few days or so ...


And, as if by magic...
On the other hand, the ADS data shows that 2017 is still chilling out on the low side of 1980.

However, the fact that 1980 was a leap year means that, when doing a comparison between the two years, a one-day discontinuity gets introduced into the day number/date after 28th Feb 2017.

Additionally, there is a 7-day gap in the data (9th to 15th April 1980) and therefore ADS have, quite reasonably, used a linear interpolation between the 8th and 16th April 1980. That means 1980 could have been lower at today's date.

Irrespective of the above, the point is somewhat moot; to all intents and purposes, the sea ice extent levels (although not necessarily the distribution/concentration) are currently virtually identical with those measured 37 years ago. Given the extreme variability demonstrated in the past, I have absolutely no opinion on whether 2017 will still have the lowest level in a week, or, for that matter, in a month, or three months or at the maximum.


On the other, other, hand, things are a bit clearer as regards any rolling 365-day average. The ADS data now shows the current 365 day average extent as being around 230K sq kms lower than the previous lowest value clocked up in 1980. The NSIDC numbers are a bit more modest, but still show this metric as ~ 85k sq kms lower than the lowest recorded during 1980.

(NB Both ADS and the NSIDC show this metric still dropping at just over 4k sq kms/day. That means, when the NSIDC data for Day-102 becomes available, the rolling average will drip to ~90k sq kms below the previous record.)


Title: Re: Sea Ice Extent around Antarctica
Post by: johnm33 on April 13, 2017, 11:15:39 AM
'meltwater' It seems to make sense most of the 'action' is happening on the northern reaches opposite Australia and the Indian ocean.
https://nsidc.org/data/bist/bist.pl?annot=1&legend=1&scale=100&tab_cols=2&tab_rows=2&config=seaice_index&submit=Refresh&mo0=03&hemis0=S&img0=extn&mo1=03&hemis1=S&img1=anom&year0=2017&year1=2016 
https://nsidc.org/data/seaice_index/
Title: Re: Sea Ice Extent around Antarctica
Post by: nicibiene on April 13, 2017, 12:14:27 PM
Quite impressive that blue spot at West Antarctica.  :o

Interesting also if you watch the massloss of the Western Antarctica Icesheet-especially in winter mass loss continues... and it would have been interesting to have more datas from July 2016 on.

But they stopped with public datas...why?  >:(

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on April 13, 2017, 02:43:32 PM
The 1980s was the decade with the lowest Antarctic Sea Ice. Despite losing its lowest ever place to 1980, Antarctic Sea Ice extent as measured by Jaxa is still more than 1.3 million km2 (20 %) below the 1980s average. ( 1980 itself was a real outlier). So my one brick out of three is still intact - maybe something is stirring in the Antarctic.

Will there be data on any impact of the record low sea ice in the Austral summer on the ice shelves ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on April 13, 2017, 03:49:28 PM
Sea ice area calculated from NSIDC sea ice concentration is second place too, but  closer to become third. Here are the rankings bottom four:

extent SH
2006-04-12 5.639845
1981-04-12 5.505485
2017-04-12 5.008667
1980-04-12 4.937324

area SH
2006-04-12 3.960018
1981-04-12 3.760847
2017-04-12 3.609386
1980-04-12 3.371592

Graphs attached ( with leap year offsets compensated by aligning the data to the true solar equinoxes).
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on April 13, 2017, 07:10:29 PM
The "lowest 4 as at 12th April" provided by Wipneus gives some insight as to the ridiculous intra-year (never mind inter-year) variability exhibited in the Antarctic.

The years 1980, 1981 and 2006 each feature in that "lowest 4", so let's play a quick game of "guess what happened next".

Using the NSIDC monthly figures for area, we see that...

1980 is currently lowest for April, May and June, and 2nd lowest for July. However, by October, it had slipped out to 33rd of 38.

In April and May of the following year, 1981, sea ice area was back down to 2nd lowest, but promptly shot back up to 29th by October, and 34th (of 39) by November.

2006 is 3rd lowest for April and 5th lowest for May, but then ends up with 33rd, 34th and 36th for August, September and October, respectively.

These years are by no means outliers in this respect; 2000, 2001 and 2002, to name just a few, also exhibit such extreme variability.
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on April 14, 2017, 10:17:06 AM
I'm curious as to whether that indicates ongoing basal melt and the spread of easy to freeze fresh water and if that's the case what implications it has for future ice loss.

You may find some material of interest if you have a little trawl through the British Antarctic Survey site.

For example, there was a brief press release last year concerning the impact of warming waters...
https://www.bas.ac.uk/media-post/ocean-warming-primary-cause-of-glacier-retreat/ (https://www.bas.ac.uk/media-post/ocean-warming-primary-cause-of-glacier-retreat/)

There is also an abundance of metadata at...
https://data.bas.ac.uk/datasets.php?topic=Cryosphere&term=Glaciers%2FIce+Sheets (https://data.bas.ac.uk/datasets.php?topic=Cryosphere&term=Glaciers%2FIce+Sheets)
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on April 21, 2017, 01:12:59 PM
As of April 20th Jaxa measure of extent is 5,889,051, a large 167,000 km2 increase in a day. Average April per day increase is 112,000, also a bit higher than normal (?what normal?). Still 2nd lowest extent in satellite record (NSIDC Charctic), and still over 1 million km2 below 1980s average.

Jaxa also still showing strong sea ice drift away from Antarctica in Ross and Weddell seas.
Title: Re: Sea Ice Extent around Antarctica
Post by: nicibiene on April 24, 2017, 01:39:39 PM
Quite warm in Antarctica too at the moment....

Also a remarkable anomalies in albedo warming potential- here a site with compairision of several years:
https://sites.google.com/site/cryospherecomputing/warming-potential/Albedo-Warming-Overview
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on April 24, 2017, 09:03:05 PM
Quite warm in Antarctica too at the moment....

Also a remarkable anomalies in albedo warming potential- here a site with compairision of several years:
https://sites.google.com/site/cryospherecomputing/warming-potential/Albedo-Warming-Overview (https://sites.google.com/site/cryospherecomputing/warming-potential/Albedo-Warming-Overview)
That site is run by Nico Sun, who posts on the ASIF under the handle of "Tealight".

Here is the link to his thread on Albedo Warming Potential...

http://forum.arctic-sea-ice.net/index.php/topic,1749.0.html (http://forum.arctic-sea-ice.net/index.php/topic,1749.0.html)
Title: Re: Sea Ice Extent around Antarctica
Post by: rboyd on April 28, 2017, 09:02:24 PM
2014 = -28.22 kWh/M2 (yes, negative)
2015 = -21.56 kWh/m2 (yes, negative)
2016 = +12.96 kW in 2006 (flip to positive)
2017 = +59.549 kWh/m2

A turn around of nearly 90 kWh/m2 in 4 years, that's a lot of extra heat being taken into the southern ocean. The start of "Antarctic Amplification"?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on May 02, 2017, 03:19:01 PM
Sea ice extent per Jaxa on 1st May 7,100,141, somewhat lower per day extent increase over the last few days despite strong outward sea ice drift in Weddell  and Ross seas.

Jaxa sea ice drift for antarctica also somewhat spectacular today:-
- https://ads.nipr.ac.jp/vishop.ver1/vishop-monitor.html?S (https://ads.nipr.ac.jp/vishop.ver1/vishop-monitor.html?S)

And from the weather-forecast.com link  below one can see where the name "The Furious Fifties" came from to describe the Southern Antarctic Ocean. I would not want to be on anything that floats down there at the moment.

http://www.weather-forecast.com/maps/Antarctica?over=pressure_arrows&symbols=none&type=wind (http://www.weather-forecast.com/maps/Antarctica?over=pressure_arrows&symbols=none&type=wind)



Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on May 22, 2017, 06:12:42 PM
Extent and area growth have slowing or even reversing, at least by the NSIDC sea ice concentration.

Both area and extent still occupy 2nd lowest place. Moving closer to 1980.

extent SH
1990-05-21 10.225472
2007-05-21 10.199011
1987-05-21 10.163478
2002-05-21 10.006257
2006-05-21 9.979037
1981-05-21 9.932460
1983-05-21 9.921044
1986-05-21 9.887104
2017-05-21 9.565976
1980-05-21 9.449800

area SH
1987-05-21 7.916975
1984-05-21 7.913605
2002-05-21 7.747078
1988-05-21 7.607524
1986-05-21 7.580002
2006-05-21 7.561909
1981-05-21 7.516775
1983-05-21 7.369399
2017-05-21 7.064158
1980-05-21 6.901739
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on May 22, 2017, 06:55:34 PM
Hullo Wipneus,
I was waiting to see if the last 2 days jaxa nos were just a blip. If they are not, time once again to wonder what the hell is goi g on down there ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on May 23, 2017, 03:01:06 PM
If seen by NSIDC, Jaxa, U-Hamburg products the dip is real.
 
Area has partly recovered again today, without affecting rankings.  That is life for the followers of the day-to-day changes.

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on May 24, 2017, 02:27:17 PM
Given the very strong sea ice drift around Antarctica, the marked reduction in refreezing rates in the last 4 days may be a temporary blip.(63,000 km2 per day cf 135,000 per day in the previous 10 days).
Nevertheless, it remains that from Early Nov 2016 to early April 2017, a period of over 150 days, sea ice extent (per Jaxa) was the lowest in the satellite record, and since then (a period of over 40 days) sea ice extent has been and remains second lowest, (nearly 1 million km2 lower than the 1980s average).

Significant ? Je ne sais pas. Worth keeping an eye on ? Methinks yes.

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on May 30, 2017, 03:49:29 PM
On May 27 the Jaxa extent measure become more than 1 Crore m2. (Now at 10.3 million m2).
According to NSIDC's Charctic graph, also moved from 2nd to third lowest, though returning to 2nd lowest or lowest is very possible in the next few days. Is also currently 987,000 km2 (8.7%) below the 1980s average.
Sea ice drift out northwards from Ross and Weddell seas remains impressive.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on May 30, 2017, 05:41:55 PM
And the lack of sea ice in West Antarctica is equally impressive!
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on June 10, 2017, 02:15:54 PM
And the lack of sea ice in West Antarctica is equally impressive!

Antarctic sea ice extent (Charctic image) seems to be still 3rd lowest (just). But (Jaxa data) only 0.5 million km2 less than the 1980's average compared with a max of 1.4 million km2 earlier in the year.
This difference is almost entirely confined to West Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on June 17, 2017, 12:13:04 PM
Antarctic sea ice extent still seems to be third lowest (from Charctic), (and from Jaxa) 0.7 million km2 (5.5%) below the 1980's average, and 2 million km2 (14% 19 days ) below 2014 (maximum year).

So no real change in this persistent low extent. But is it the case of the dog that did not bark? One can do nowt but wait.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on June 17, 2017, 06:37:43 PM
Yes, with area the position is 6th lowest. Note that 2016 was at this date late year nowhere near the bottom 10 yet.

extent SH
1995-06-16 13.111516
1993-06-16 13.081682
1997-06-16 13.059745
1992-06-16 12.840877
1983-06-16 12.797465
1987-06-16 12.789769
1980-06-16 12.766877
2017-06-16 12.548448
1986-06-16 12.541214
2002-06-16 12.363365

area SH
1997-06-16 10.082896
1992-06-16 10.069927
1995-06-16 10.012473
1987-06-16 9.998876
2017-06-16 9.883237
1991-06-16 9.866560
1983-06-16 9.826909
1980-06-16 9.808612
2002-06-16 9.718470
1986-06-16 9.363011
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on June 17, 2017, 06:49:35 PM
Hullo wipneus,
I looked at NSIDC to find Antarctic sea ice spreadsheets and only found Arctic. Alcohol may have been involved. It is all because in my head there are 3 things of which we humans are most ignorant of re planet earth of which no #1 is the Antarctic. Imagine I am a bloodhound, give me a rag to scent and I will be on the hunt.

Regards,

Gerontocrat.


Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on June 22, 2017, 02:50:46 PM
In the last 5 days sea ice extent has increased by an average of 62,000 km2 per day, 45% less than the average increase since April 1.(JAXA data). However, it does seem that much of the difference in daily changes can be attributed to the strength and direction of sea ice drift, in itself a function of the violent weather down there.

Nevertheless sea ice extent in Antarctica according to NSIDC's Charctic is now tied with 2002 as lowest in the satellite record. Extent is nearly 1 million below that of the 1980's. Antarctic Sea Ice extent has been lowest, 2nd lowest and briefly 3rd lowest for some 225 days (since early Nov 2016).
Is this of note?

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on June 27, 2017, 03:02:18 PM
Antarctic Sea Ice Extent remains lowest in satellite record (Jaxa and NSIDC). Low daily increases in extent seem once again to be mostly due to strong sea ice drift parallel to coast and onshore.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on June 27, 2017, 05:22:43 PM
The negative anomaly is entirely related to West Antarctica. Will be interesting to see if the sea ice will catch up with other years later this season.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on June 27, 2017, 08:01:42 PM
The negative anomaly is entirely related to West Antarctica. Will be interesting to see if the sea ice will catch up with other years later this season.
In a month or two those gentle curves on the graph go all wobbly until melt sets in again. Maybe difficult to see any real trend until that melt gets going?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on June 28, 2017, 12:34:21 PM
Here are some numbers. (I like numbers).

Jaxa data as at June 27
      
Extent in km2    13,327,296
   
Compared with:-    Difference    
                                   km2    %
2014 (max year)   -2,499,716   -16%
2015                   -2,119,571   -14%
2016                   -1,041,200   -7%
1980's (min yrs)   -1,024,239   -7%

And it is still all about West Antarctica.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on July 01, 2017, 03:41:34 PM
More numbers

Jaxa data as at June 30      
Extent in km2    13,568,681    
Compared with:-    Difference    
                                km2              %
2014 (max year)   -2,508,157   -16%
2015                           -2,153,427   -14%
2016                           -1,008,448   -7%
1980's (min decade)   -1,040,133   -7%

Antarctic Sea Ice has been lowest (in the satellite record) , 2nd lowest or third lowest for nearly 240 days. It is currently lowest.
In the second half of June average refreezing has been 84,000 km2 per day, just 74% of the average since April 1 this year. This is odd given the time of year and a somewhat chilly Antarctic.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on July 06, 2017, 03:25:17 PM
Antarctic Sea Ice Extent about to slip from lowest to 2nd lowest behind 1986.
(http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/ (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/)).

Still an impressive reduction over the last 3 years.

Title: Re: Sea Ice Extent around Antarctica
Post by: Darvince on July 09, 2017, 11:18:22 AM
I have often wondered throughout this freezing season whether we have seen a switch back to the low ice of the 70s and 80s, but all the comments about how Antarctic sea ice is so intensely variable have kept me from stating it outright.

However, we are now in July, less than a month away from when Antarctic ice begins its wobble about the maximum, and it's still lowest on record on JAXA and seems like it's going to stay that way unless we get a 300k km² growth spurt over the next two days.

Compared to 1986 the winds seem like they've been much stronger this year, as the sea ice shape looks more like the September shape of the 80s rather than its July shape.
ftp://sidads.colorado.edu/pub/DATASETS/nsidc0051_gsfc_nasateam_seaice/final-gsfc/browse/south/daily/1986/nt_19860708_n07_v1.1_s.png
ftp://sidads.colorado.edu/pub/DATASETS/nsidc0081_nrt_nasateam_seaice/browse/south/nt_20170707_f18_nrt_s.png
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on July 17, 2017, 03:14:01 PM
Antarctic Sea Ice Extent once again lowest in the satellite record.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on July 17, 2017, 04:29:41 PM
Also area has taken the lowest position. Looking at the graphs, extent will likely stay lowest a bit longer, area probably not.

extent SH
1985-07-16 15.775432
1995-07-16 15.732109
1980-07-16 15.615618
1989-07-16 15.592934
1990-07-16 15.502736
1986-07-16 15.480906
2002-07-16 15.480702
1983-07-16 15.480661
1991-07-16 15.451098
2017-07-16 15.024859

area SH
1982-07-16 12.455222
1995-07-16 12.433007
1986-07-16 12.352278
2001-07-16 12.349878
1987-07-16 12.341766
2011-07-16 12.240798
1990-07-16 12.224225
1991-07-16 12.200350
1980-07-16 12.178648
2017-07-16 12.141301
Title: Re: Sea Ice Extent around Antarctica
Post by: AbruptSLR on July 18, 2017, 04:13:21 PM
Modeling Antarctic sea ice is complex and modeling the implications of changes in Antarctic sea ice is even more complex (i.e. Hansen's ice-climate feedback is made more positive by the presences of this sea ice):

Roach, L. A., Dean, S. M., and Renwick, J. A.: Consistent biases in Antarctic sea ice concentration simulated by climate models, The Cryosphere Discuss., https://doi.org/10.5194/tc-2017-131, (https://doi.org/10.5194/tc-2017-131,) in review, 2017.

http://www.the-cryosphere-discuss.net/tc-2017-131/ (http://www.the-cryosphere-discuss.net/tc-2017-131/)

Abstract. The simulation of Antarctic sea ice in global climate models often does not agree with observations. In this study, we examine the compactness of sea ice, as well as the regional distribution of sea ice concentration, in climate models from the latest Coupled Model Intercomparison Project (CMIP5) and in satellite observations. We find substantial differences in concentration values between different sets of satellite observations, requiring careful treatment when comparing to models. As a fraction of total sea ice extent, models simulate too much loose, low-concentration sea ice cover throughout the year, and too little compact, high-concentration cover in the summer. In spite of the differences in physics between models, these tendencies are broadly consistent across the population of 27 CMIP5 simulations, a result not previously highlighted. Targeted model experiments with a coupled ocean – sea ice model show that over-estimation of low-concentration cover is partially determined by choice of constant floe diameter in the lateral melt scheme. This suggests that current sea ice thermodynamics contribute to the inadequate simulation of the low-concentration regime.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on July 22, 2017, 02:54:47 PM
It seems to be a rule that the more we need to know about something the less we do. The Antarctic, the Oceans, the Arctic come to mind.

Meanwhile, despite ferocious sea ice drift leading to high daily increases in extent at a time one expects a reduction, Antarctic Sea Ice is currently lowest in extent in the satellite record.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on July 31, 2017, 01:27:28 PM
Jaxa data continues to show above average refreezing. The extent which early in the year was about 1.4 million km2 less than the 1980's average has shrunk to about 0.3 million km2,  to the point the Charctic graph shows the 2017 line rapidly merging into the spaghetti of previous years.

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 01, 2017, 11:35:10 AM
What a difference a day makes. Just when I thought that it was time to forget about Antarctic sea ice extent for a bit, on July 31 daily extent dropped by 80 thousand km2. An oddity ? - will it persist?
Title: Re: Sea Ice Extent around Antarctica
Post by: Watching_from_Canberra on August 02, 2017, 07:17:51 AM
An oddity ? - will it persist?

Well, according to JAXA, Antarctic extent has dropped more in the last 2 days than Arctic extent!
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 02, 2017, 07:32:22 AM
It may have something to do with the 9 and 10 meter waves on all sides of the sea ice.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on August 02, 2017, 07:36:17 AM
An oddity ? - will it persist?

Well, according to JAXA, Antarctic extent has dropped more in the last 2 days than Arctic extent!

events like this on the 1st of a month have to be taken with a prise of salt, at times thera are correction and/or algorithm changes. dunno the details but it has been mentioned a few times.

does not mean it didn't happen, just that there might be some exagerations.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 02, 2017, 07:57:36 AM
Last year there was a dive in September. The loss was never really recovered. (https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on August 02, 2017, 08:30:36 AM
September is Spring down here..........daylight hours are rapidly increasing.....even now .. 02/08.... we are getting one minute extra per day
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 02, 2017, 04:28:32 PM
It may have something to do with the 9 and 10 meter waves on all sides of the sea ice.
The sea ice drift is certainly humongeous as in the image below. (If that happened in the Arctic on a daily basis?) But it is not out of the ordinary down there. In winter I have noticed the difference in extent gain from one day to another can be well in excess of 100,000 km2 as the direction of drift switches from off to on shore or vice versa. But that does not seem to be the case over the last few days. Note the strong off-shore drift out of the Weddell sea.

But two days of this odd extent loss is not enough to see if something of note is happening down there.

ps: 2017 sea ice extent is currently 0.5 million km2 less than 2016
pps: could not resist adding the image of the antarctic jet stream. How can anything from further north get through that.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 03, 2017, 05:37:40 AM
About another 50k drop today. It is still going the wrong way. This could be a big problem if it continues.  Now at 16,319,492 km2 down about 210k since 7-30-2017
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 03, 2017, 01:42:46 PM
(Jaxa Data) The last three days see a 210,000 km2 reduction in sea ice extent compared with an average increase of about 200,000 at this time of year, i.e. circa 400,000 km2 or 6 days the wrong way.

These wobbles do start to occur from about now as refreezing rates start to quickly drop as maximum approaches in early September. But I have not been able to find  a drop in extent this early in August anywhere in the satellite data. However, it still remains to be seen whether 2017 gets and stays below 2002 and then 1986.

Antarctic sea ice has been lowest, 2nd or 3rd lowest for 270 days.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on August 03, 2017, 04:50:15 PM
Last years drop....2016....was 3+ weeks early.  I certainly would NOT expect a melt season that started ANOTHER 3+ weeks earlier than that.  THAT....would be astonishingly early.  Everyone here knows the DIRECTION of where things are going....we just don't KNOW how quickly we will proceed.  If we WERE to amazingly start that early this year.....a higher level of alarm bells in the scientific community would no doubt go off. :-[

The POLITICAL ramifications are going to follow the PHYSICAL FACTS.

The world is getting closer to a day when we will HAVE TO initiate a "Marshall Plan" to slow down global warming.  That point is starting to come into focus....with the US being the laggard.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 03, 2017, 05:19:40 PM
Here is the NSIDC  Daily numbers

2017,    07,  29,     16.496  x 106  km2
2017,    07,  30,     16.586   Peak?
2017,    07,  31,     16.536
2017,    08,  01,     16.477
2017,    08,  02,     16.417

And Graph
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 04, 2017, 05:39:27 AM
Minor JAXA drop for 8-3-'17 of 8,076 km2 leaving SIE at 16,311,416 km2.
For the time of year, not going up is almost as bad as going down.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 04, 2017, 02:52:37 PM
With a drop of just 8k km2 as opposed to an average increase of around 70k km2, the wrong way figure over the last 4 days is nearly 500,000 km2 or one week's expected freeze.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 05, 2017, 05:39:31 AM
Nominal gain of 9,311 km2 for SIE landing at a total of 16,320,727 km2.
Looks like a stall at the least, which really bites for the time of the year, going by which there should still be some growing vs. a stall.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 05, 2017, 12:45:03 PM
If Extent Gain from now to maximum is at the average of the last 10 years, Antarctic sea ice extent will max out at around 17.8 million km2, some 0.2 million below the 2002 maximum ((2002 melt then became far less than the average.),0.7 million less than 2016.

There is therefore a good chance 2107 maximum will be lowest in the satellite record. The table below shows how little difference there has been in total melt over the last 10 years.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 05, 2017, 10:47:18 PM
Looking at the high waves and SST's around the sea ice of Antarctica, it appears that there is really nowhere left much for growth because of these. A similar thing happened earlier this year in the Arctic. Therefore the current situation may persist until the end of September there(Ant.) when the true melting begins. The global sea ice extent chart is going to look ridiculous by the time this year is over. Perhaps the sea temps will limit the growth of sea ice in both regions a little more each year. What a phenomena, to reduce sea ice by disallowing growth beyond a certain point.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 05, 2017, 11:27:28 PM
Sea ice concentration vs sea water temps at a half meter down. The is very little room for growth where the water is cold enough, and the waves are too rough for any cooling. The darkest shade is where the water is at or close to -1.8oC. CLICK IMAGE
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 06, 2017, 05:48:46 AM
So much for theories. A big jump back up to 16,471,947 km2. Let's see what the long range does.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 09, 2017, 02:50:04 PM
So much for theories. A big jump back up to 16,471,947 km2. Let's see what the long range does.
It goes down, it goes up, it goes down again.
On average the extent gain is 92% done. Just 1.3 million km2 to go.
I am still plumping for a max extent of 18 million km2 +/- 0.25 million km2
Title: Re: Sea Ice Extent around Antarctica
Post by: Hyperion on August 10, 2017, 12:04:05 AM
Meanwhile its 4.1C on the Antarctic Peninsular, and Raining. In the middle of the coldest month in Winter.
https://earth.nullschool.net/#2017/08/10/2100Z/wind/isobaric/1000hPa/overlay=temp/equirectangular=-169.52,-85.14,822/loc=-63.535,-69.962

Would have put this in "whats New in Antarctica" but this happened last year too.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 10, 2017, 05:41:41 AM
Antarctic SIE has practically stalled again with a couple of nominal gains in a row.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 10, 2017, 01:22:31 PM
Herewith a little table indicating the possibilities for the maximum extent (per JAXA).
Three indicate a tendency for below 18 million km2, while 2012, (highest remaining freeze in the last 10 years,) shows a max of 18.4 million km2. If we had a poll, I would still be going for 18 +/- 0.25 million km2.

Half? off-topic.A real possibility of global sea ice extent max of 22 million km2 or even a bit less in early or mid-September ? That would raise some eyebrows ?
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on August 10, 2017, 02:31:24 PM
Old gits with some background in electronics, such as myself, might remember the Signetics 555 timer, as it was almost ubiquitous in circuit design a few decades ago.

It was just that bit of weird arcane knowledge which caused me to do a quick double-take at the Antarctic tab in my JAXA/ADS extent tracker today. The rolling 365-day average has just dropped to  10.536 million sq kms, which displays on my spreadsheet as now being 555k sq kms lower than the previous lowest, which was set way back in August of 1980.
(How time[r]s have changed.  ;))

This current figure of 10.536 is still dropping at ~1.5k/day, and, considering that the 2016 Antarctic extent values didn't start to plummet until next month, it is definitely possible that, during September, the rolling-365 could end up more than 1 million sq kms below the 1980's average of 11.486 million sq kms.

The equivalent rolling-365 taken from the NSIDC dailies lags somewhat at "only" 408k sq kms lower than the erstwhile lowest ever NSIDC value from 1980; a difference of 147k sq kms between itself and the equivalent ADS reduction. However, the delta between the two sets of data has remained pretty constant for some time now.

The ADS rolling-365 equalled the 1980 record-low value on January 26th of this year; on the same date, the NSIDC equivalent was 138k higher than its 1980 figure.

The NSIDC rolling-365 attained parity with its equivalent 1980 record-low on March 26th, by which time the ADS number was 142k sq kms lower than its previous record low.

As mentioned above, the current amount by which the ADS record-low has been reduced now stands at 147k more than the equivalent NSIDC reduction. In other words, the delta between the two sets of data has changed by about 9k in a period of around 6 or 7 months.

So, the next time you hear one of the flat-earth brigade spew forth some drivel about "gains in Antarctic sea ice more or less cancel out losses in the Arctic", you'll be able to tell them precisely which orifice they're talking out of.   ;D


I was just about to hit the "Post" button, when the old Red Alert informed me that another comment had arrived whilst I was typing.


Apropos of gerontocrat's musing about the September value, it will also be very interesting to see what happens come November, as that is traditionally the time of the global sea ice maximum.

A few days ago, on another thread, I posted a chart showing the recent behaviour of the rolling-365 for global sea ice, and I've appended that below. (It has dropped another 7k sq kms in the intervening 5 days.)

As the current value is ~ 22.318 million sq kms, one cannot help but wonder when that might drop below 22? In the last 4 and a half months, it has lost ~ 318k sq kms, so it is not outwith the realms of possibility that we could see sub-22 by around Christmas time - just what we don't need as a present!

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 14, 2017, 01:20:14 PM
Jaxa Sea Ice Extent data. Average refers to 2007-2016.

By now on average 93% of extent increase is done for the year, with just over 1 million km2 extent gain to go.. The data suggests a maximum extent of between 17.7 and 18.3 million km2. If Antarctic conditions are similar to those in 2016, i.e. in reduced extent increases, then this favours an outcome at the lower end of the range and an early date for maximum.
Title: Re: Sea Ice Extent around Antarctica
Post by: Tor Bejnar on August 14, 2017, 08:39:39 PM
I wonder what affect Iceberg A-68 (recently part of Larsen Shelf) will have on the Antarctic sea ice near it, come SH spring/summer.  Will all the fractures cause an early dispersal? (today's PolarView image (http://bslmagb.nerc-bas.ac.uk/iwsviewer/?image=DataPolarview/111_S1jpeg2000_201708/S1A_IW_GRDH_1SDH_20170814T133301_5D36_N_1.8bit.jp2))
Title: Re: Sea Ice Extent around Antarctica
Post by: Bill Fothergill on August 14, 2017, 09:29:00 PM
@ gerontocrat

It will be interesting indeed to see how your projections regarding the max turn out.

During 2016, the max of 18.5 million sq kms occurred at the ridiculously early date of 29th August. It then dropped rapidly over a period of ~2 weeks, before spending the subsequent ~7 weeks in various of the lowest 4 positions. Of course, as we all know, it started to seriously separate from the rest early in November.

Looking at inter-annual differences on specific dates can be somewhat prone to cherry picking, but it can be educational to look at how the rolling 365-day average has differed from year to year.

As the latest available data is for the 13th August, here's how the rolling-365 shapes up on that date for each year from 2000 onward...

 Year      Average extent (in millions of sq kms)
2000      11.82
2001      11.79
2002      11.25
2003      11.75
2004      11.77
2005      11.63
2006      11.26
2007      11.51
2008      12.24
2009      11.93
2010      11.93
2011      11.56
2012      11.86
2013      12.25
2014      12.69
2015      12.69
2016      11.57
2017      10.53

That's a reduction of a frankly astonishing 2.16 million sq kms in the last 2 years. Hopefully next year will be nowhere near as bad! (To add a bit more context, the overall average from Jan 1979 to Dec 2016 was 11.714 million sq kms.)

Attached below is a zoomed view from ADS, and, with a bit of multiple-imaging and cropping, I've managed to highlight both 2016 and 2017. There is still a bit of "low hanging fruit" over the next 3 or 4 weeks, but, by then, the reduction rate in the rolling 365-day average should - hopefully - ease off.

The second attachment consists of two simple tables; the first shows the daily values on the 13th August for each year, and the second gives the daily values for the 25th October - a date approximately as far after the max as we currently are before it.

I really hope that the maximum will be considerably later than 2016, otherwise I'll seriously start to worry about the Antarctic as well.

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 14, 2017, 10:49:24 PM
Good heavens Bill.
What else have you got inside your computer?

Your image as an oldie unable to function without a few beers is under threat.

But - if the Antarctic max is early, and as is also very possible, the Arctic min staggers along through September, whither the global sea ice extent ?
"I want to know".
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 14, 2017, 11:22:27 PM
 gerontocrat
But - if the Antarctic max is early, and as is also very possible, the Arctic min staggers along through September, whither the global sea ice extent ?
"I want to know".
Maybe the Arctic doesn't even get any real freezing momentum until October. Hence the global extent thread that I just started. I could be wrong, but I think that to be the thing to watch.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on August 18, 2017, 02:54:18 PM
NSIDC talk.
Most of the year extent was among the lowest for the day while area was more near "normal".  Area has not increased much in the last two weeks and is now the lowest for the day. In the same period extent continued to grow slowly and is now third lowest, very close to numbers 2 and 4 (1983,1986).

extent SH
2015-08-17 17.670308
1990-08-17 17.651459
2003-08-17 17.588286
1993-08-17 17.508462
2007-08-17 17.479746
1987-08-17 17.456403
1986-08-17 17.188608
2017-08-17 17.182489
1983-08-17 17.181426
2002-08-17 16.885662

area SH
1980-08-17 13.952788
2007-08-17 13.898502
2015-08-17 13.896400
2005-08-17 13.867166
2003-08-17 13.770086
1979-08-17 13.741580
1983-08-17 13.714794
1986-08-17 13.576629
2002-08-17 13.363494
2017-08-17 13.338877
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on August 18, 2017, 09:17:06 PM
Can it outdo 2016?  Certainly possible...looks like it is trying to "roll over".  Just the fact that it is close to the same EARLY max time is impressive.  If it ends up being EARLIER and LOWER would be yet another shot across the bow as we move closer still to the day when a "renewable energy Marshall Plan" is initiated.

Title: Re: Sea Ice Extent around Antarctica
Post by: RealityCheck on August 19, 2017, 09:02:32 AM
Tigertown, where have you opened the global sea ice extent thread please? Thanks.
Title: Re: Sea Ice Extent around Antarctica
Post by: RealityCheck on August 19, 2017, 09:07:57 AM
Also, given your 'name' here, can you identify the species in my photo? (O-T I know, but a once-off 😁)
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on August 19, 2017, 01:07:23 PM
Tigertown, where have you opened the global sea ice extent thread please? Thanks.

It is under The Rest category.  http://forum.arctic-sea-ice.net/index.php/topic,2136.0.html

My namesake is from the development I live next to, so I am no expert on cats, despite the limited coincidental knowledge that I have of them. I would guess a Bengal Tiger.
Title: Re: Sea Ice Extent around Antarctica
Post by: RealityCheck on August 19, 2017, 06:54:46 PM
Thanks TT
(And it's a Sumatran Tiger... the image stayed with me - the parallels with humanity, and all that. A species living in a limited space, and trapped like this one was. Except of course, as humans, we're destroying both his habitat and our own... Back to on-topic now.. )
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 21, 2017, 02:09:20 PM
JAXA Data.

Since 14th August, Antarctic sea ice extent gain has been well above the average, almost a mirror of the low extent loss in the Arctic.
I attach a table and graph.
I also attach an extract of the next 5 day max temperature image from cci-reanalyzer. Note the "feathers" at the top and bottom? I've never seen that before. Mind you, it is very windy down there at the moment - thin sea ice at the margins being swirled into patterns?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 26, 2017, 02:00:41 PM
It is 5 days since the last posting so here are some more (JAXA) sea ice extent numbers.

N.B. Not predictions - in the last 2 previous years the maximum extent date has been 29 Aug (2016) and 2nd October (2015). Merely a range of possible outcomes is presented in the table below.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 27, 2017, 03:07:37 PM
JAXA have a 25 thousand km2 extent loss on 26th August, 0.76 million km2 less than 2016. 2002 still lowest - just.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 28, 2017, 02:34:12 PM
(JAXA Data) And another 60 thousand km2 extent loss on 27th August. 85k in two days.
Two days losses not enough to state current extent is the maximum with confidence.
If 2017 replicates 2016 over the next 3 weeks - good golly, miss molly! (see graph below).
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 29, 2017, 01:39:27 PM
Another 40k km2 extent loss on the 28th August according to Jaxa.
That is 125 thousand extent reduction in three days when one would on average expect a gain of a similar amount.

Still too early to call a maximum on an unprecedented date of 26th August, methinks.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on August 29, 2017, 07:21:25 PM
It may be too early to call (as you say).... but a max in Antarctica now is a very real possibility....especially after last years early max.  Two years in a row would certainly heighten the worry in the science community....although it is already on heightened alert.

The only people not worried would be the people lying about it like Hannity, FOX News, dimwit Donnie, and many GOP congressmen supported by the O & G industry.

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on August 30, 2017, 02:43:26 PM
Jaxa extent down by a statistically insignificant 6 k km2 on the 29th. Often this seems to herald a switch. Certainly not able to call a maximum yet.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 01, 2017, 02:37:02 PM
Actual RAIN (not snow) forecast on Antarctic coast.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on September 02, 2017, 10:12:27 AM
Another extent drop and is now the lowest ever observed. Meanwhile it's going to be a strong warming, more than 4 °C anomaly forecasted in Antarctica
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on September 02, 2017, 10:40:06 AM
Antarctica SIE right now reminds me of a staggering ole' drunk trying to stay on his feet.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 02, 2017, 02:11:42 PM
Antarctic sea ice extent (JAXA data) reached a maximum of 17.640 million km2 on 25th August. 7 days later it is 125,000 km2 less at 17.515 million km2. In this period the average gain is 250,000 km2.
However, there are often big ups and downs in September, so a surprise may be in store either way, especially given average date of maximum is more like around the 20th September. If 25th August ends up as the date of maximum (2016 was on 29th August) - good heavens.

So, like a fool I will prognosticate a maximum extent of less than 18 million km2.

Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on September 03, 2017, 04:02:06 PM
NSIDC SIE for Antarctica has really leveled off or stalled. JAXA is similar, but they have not updated for 9-2-2017 yet.(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Sea Ice Extent around Antarctica
Post by: steve s on September 03, 2017, 06:35:20 PM
Looks to me like the sea ice extent took a step downward in August 2016, and stayed down thereafter. An energy distribution change of some kind. What other event or events may be time correlated?

I wrote 'may' because the other events may be earlier or later due to transmission effects and the cause may be a separate matter, but the step nature of the shift is clear. The shift is as interesting a phenomenon as it is frightening.   
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on September 03, 2017, 07:08:49 PM
Looks to me like the sea ice extent took a step downward in August 2016, and stayed down thereafter. An energy distribution change of some kind. What other event or events may be time correlated?

I wrote 'may' because the other events may be earlier or later due to transmission effects and the cause may be a separate matter, but the step nature of the shift is clear. The shift is as interesting a phenomenon as it is frightening.
Do you mean to say September 2016?
Title: Re: Sea Ice Extent around Antarctica
Post by: steve s on September 03, 2017, 07:43:04 PM
Oops I was misreading where months begin in your graph. The change began around or just after the beginning of September 2016 and took 10 days to 2 weeks to complete, as I now read the graph.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 04, 2017, 11:12:23 AM
JAXA DATA

What an end of season at both ends of the earth.
Table 1 shows some possible outcomes, including August 25th as the maximum
On 5th Nov 2016 sea ice extent became the lowest in the satellite record, and stayed that way for over 150 days. Since then, apart from a few days at 4th lowest, extent has been 3rd, 2nd or 1st lowest. We are in the third year of significant decline. (see Table 2)

In 2016 extent dropped suddenly after 29th August - (see graph). Will 2017 follow this pattern?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 06, 2017, 11:12:11 AM
With 3 days increase in extent, 5th September a wopping 189,000 km2, The maximum extent to date is now 17.72 km2, i.e. 25th August is NOT the date of maximum.
Title: Re: Sea Ice Extent around Antarctica
Post by: AbruptSLR on September 07, 2017, 05:39:40 PM
I have the feeling that with continued climate change we had better get used to 'perfect storm' occurrences, as they will soon be common place events:

Title: "Record-low 2016 Antarctic sea ice due to 'perfect storm' of tropical, polar conditions"

http://www.spacedaily.com/reports/Record_low_2016_Antarctic_sea_ice_due_to_perfect_storm_of_tropical_polar_conditions_999.html (http://www.spacedaily.com/reports/Record_low_2016_Antarctic_sea_ice_due_to_perfect_storm_of_tropical_polar_conditions_999.html)
Title: Re: Sea Ice Extent around Antarctica
Post by: steve s on September 07, 2017, 07:23:30 PM
Last year's sea ice extent a perfect storm of coincidences? Then why does this year seem so similar? I find it much easier to imagine a single driver than the squared product of low probabilities.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on September 07, 2017, 09:53:20 PM
Steve S.....absolutely right.  This is just the continuation of the basic physics in play.  And as temperatures continue to rise....along with sea levels....the science deniers will continue to mislead and lie.

FOX News has been lying about global warming for over 20 years.....and they were the biggest supporter of SCROTUS.

Donnie Trump, FOX, Bastardi, Hannity, Rick Scott, Mike Pence, Mitch McConell, Paul Ryan, Marco Rubio, etc.....

But to get back to your point.....I look for a continuation of the drop in global ice, and an acceleration of it...
Title: Re: Sea Ice Extent around Antarctica
Post by: AbruptSLR on September 08, 2017, 05:18:32 PM
Obviously, the data presented in the linked article was taken before the Antarctic sea ice extent began to retreat last year:

Katlein, C., Hendricks, S., and Key, J.: Brief communication: Increasing shortwave absorption over the Arctic Ocean is not balanced by trends in the Antarctic, The Cryosphere, 11, 2111-2116, https://doi.org/10.5194/tc-11-2111-2017, (https://doi.org/10.5194/tc-11-2111-2017,) 2017.

https://www.the-cryosphere.net/11/2111/2017/?utm_content=bufferf747e&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer (https://www.the-cryosphere.net/11/2111/2017/?utm_content=bufferf747e&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)

Abstract. On the basis of a new, consistent, long-term observational satellite dataset we show that, despite the observed increase of sea ice extent in the Antarctic, absorption of solar shortwave radiation in the Southern Ocean poleward of 60° latitude is not decreasing. The observations hence show that the small increase in Antarctic sea ice extent does not compensate for the combined effect of retreating Arctic sea ice and changes in cloud cover, which both result in a total increase in solar shortwave energy deposited into the polar oceans.
Title: Re: Sea Ice Extent around Antarctica
Post by: steve s on September 08, 2017, 07:37:23 PM
Not a surprising finding, ASLR; but there seems to have been a stair-step shift in sea ice extent, not the gradual change that article suggests. The cause of that step-wise shift begs explanation. We do not know whether the shift might repeat or the reason for its scale. Without gradualism, we are blinder than we knew.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 09, 2017, 01:06:34 PM
JAXA extent is now 17.85 million km2, i.e. increasing. Will the max be below 2016? If yes, then it will be three consecutive lower maxima from 2014.

I also attach an image from cci-reanalyzer of the 5 day max temp forecast, as it shows very well how those beautiful near perfect circles of temperature gradients are being disrupted as warmth returns.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on September 12, 2017, 07:11:57 PM
It is still possible that 2017 will record lowest maximum extent and/or lowest maximum area.
But it is getting close, and the latest maximums were reached 3rd of October 1988.

Here are the year with lowest maximums:

SH Extent

35 2008-09-03 18.297985
36 1989-09-23 18.274455
37 2002-09-09 18.116289
38 1986-09-18 18.026832
39 2017-09-11 17.969850

SH Area

35 1979-09-05 14.515589
36 2016-08-28 14.493985
37 1984-09-04 14.493378
38 1986-09-18 14.177269
39 2017-09-08 14.104656
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 14, 2017, 12:47:42 PM
JAXA Data
Extent on 13th Sept is 18.03 million km2.

On 12th September extent exceeded 2016 extent for the first time. Extent on 13th September  is now 0.2 million km2 greater than 2016 on that date.
On the other hand it still looks more likely that the 2017 maximum will be less than the 2016  maximum of 18.5 million on 29th August (see table).

For me the next two key events are
 - the maximum extent c.f. 2016,
- November 5th - on that date 2016 extent became the lowest in the satellite record. Will 2017 be the same?
Title: Re: Sea Ice Extent around Antarctica
Post by: Adam Ash on September 14, 2017, 01:28:20 PM
I have just re-read Hansen et al Ice melt, sea level rise and superstorms (2015).  Expansion of sea ice around Antartica is entirely in line with impacts of increased forcing due to CO2 et al.  The resulting increase in ice melt at both ends of the planet will lower sea surface temperatures there for a while, as well as reducing or stopping the major Meridional Overturning Circulations which screws heat distribution.  Then the increased atmospheric energy gradients (especially the much warmer equatorial regions) create storms of increasingly-unimaginable intensity. 
If we get a 'minimum maximum' around Antarctic this year I think it will be a blessing, but that's not what the forecast for the next few decades/centuries looks like, until ice melt slows again.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 15, 2017, 03:06:43 PM
The question for me is more immediate. Will 2017 continue the decline in extent started in 2014 or will it (as often happens) just merge into the pack?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on September 15, 2017, 05:59:05 PM
The question for me is more immediate. Will 2017 continue the decline in extent started in 2014 or will it (as often happens) just merge into the pack?
I think we will find out over the next two weeks where this season is going.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on September 15, 2017, 06:10:35 PM
Detailed graphs of extent and area calculated from NSIDC NT sea ice concentration attached. I highlighted the 1986 curve as well: lowest extent and area minimum until this year...
Click for a bigger picture.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 18, 2017, 03:00:57 PM
JAXA DATA
Sea ice extent now only 50,000 km2 above 2016, and at its lowest since 10 days ago.
More likely that the 18.062 million km2 extent on 12th September will be the maximum extent.
But wobbles in extent often persist until end of September before significant melt occurs.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on September 18, 2017, 09:50:35 PM
A polynya have been opening in Atlantic side. The animation from 12 to 17 September. Also cold anomalies forecasted in the Ross sea
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 20, 2017, 02:00:00 PM
JAXA DATA
Sea ice extent now 100,000 km2 below 2016, and at its lowest since 12 days ago.
Even more likely that the 18.062 million km2 extent on 12th September will be the maximum extent.
But wobbles in extent often persist until end of September before significant melt occurs.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 22, 2017, 01:07:41 PM
JAXA DATA
Extent continues to steadily decline. If it was not for the large late increase in 2015, methinks the maximum extent was definitely reached on 12 September at 18.062 million km2.
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on September 25, 2017, 07:31:51 PM
Extent drops continues. The 5-day average from NSIDC might end up being the second lowest on record trailing 1986. However, the daily maximum might be the lowest on record with a razor thin margin of 4000 km2. Let's see how fast the extent numbers drop! :)
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 26, 2017, 03:31:23 PM
JAXA DATA (Usually follows NSIDC very closely)
The continued decline in extent, despite -ve or neutral temp and SST anomalies, would make one think the 12 September extent of 18.062 million km2 was definitely the maximum, given that the date of maximum has passed for all years but one - 2015. Extent shot up from now to 2nd October. (see table). 2017 could do the same.

One might also think that 2017-2018 would continue to be a record or near record-low in daily extent. However, the previous record low maximum years of 1986 and 2002 flattered to deceive, extent gently moving into the pack as the melt season progressed. In contrast, the graph below shows how in early November 2016, extent dropped like a stone to the lowest in the satellie record and stayed there until April 2017.

The Antarctic is unpredictable.


Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on September 26, 2017, 06:50:33 PM
Update of the NSIDC graphs. Provisional maximums of area and extent are still record low, but new maximums cannot be ruled out yet (IMO).
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on September 27, 2017, 01:44:55 PM
An interesting article as it makes clear that the priority is to assist the Antarctic Tourism industry.

https://www.theguardian.com/world/2017/sep/26/antarctic-sea-ice-levels-hit-record-low-but-experts-are-not-sure-why (https://www.theguardian.com/world/2017/sep/26/antarctic-sea-ice-levels-hit-record-low-but-experts-are-not-sure-why)

Antarctic sea ice levels hit record low, but experts are not sure why

"Unpredictable nature of Antarctic sea ice levels the focus at conference of meteorology experts in Australia this week.

Better mapping and predicting these changes to aid polar shipping is the goal of the International Ice Charting Working Group Tasmanian meeting.

Unpredictable sea ice levels are creating headaches for an increasing number of tourist and research boats visiting the Antarctic.

The working group estimates about 50 cruise vessels took almost 35,000 tourists to the Antarctic last year."
Title: Re: Sea Ice Extent around Antarctica
Post by: Daniel B. on September 28, 2017, 03:00:55 PM
An interesting article as it makes clear that the priority is to assist the Antarctic Tourism industry.

https://www.theguardian.com/world/2017/sep/26/antarctic-sea-ice-levels-hit-record-low-but-experts-are-not-sure-why (https://www.theguardian.com/world/2017/sep/26/antarctic-sea-ice-levels-hit-record-low-but-experts-are-not-sure-why)

Antarctic sea ice levels hit record low, but experts are not sure why

"Unpredictable nature of Antarctic sea ice levels the focus at conference of meteorology experts in Australia this week.

Better mapping and predicting these changes to aid polar shipping is the goal of the International Ice Charting Working Group Tasmanian meeting.

Unpredictable sea ice levels are creating headaches for an increasing number of tourist and research boats visiting the Antarctic.

The working group estimates about 50 cruise vessels took almost 35,000 tourists to the Antarctic last year."

The sea ice levels have always been unpredictable.  Similar to the weather.
Title: Re: Sea Ice Extent around Antarctica
Post by: Gray-Wolf on September 28, 2017, 10:33:29 PM
I tend to think that we see periods of excessive growth when certain 'natural cycles' combine and less so under other forcings?

I think we have also been treated too, this past 40 years, a 'novel forcing' from the Ozone impacting the polar atmosphere?

We appear to now be in the 'less ice set up of Pacific 'cycles' and some repair of the Ozone?

On top of all that we have the warming that has been 'locked out' of Antarctica (over the period where naturals and ozone hole worked to expand Sea Ice?) that now appears to be working back into the Continent?

I think we have a few years of this low finish, high loss, high calving environment ahead?

I just hope we don't trip over any tipping points, esp around the Peninsula, if we do see a more 'arctic' version of Antarctica in terms of melt rates and sea ice cover?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 04, 2017, 11:37:18 AM
JAXA DATA
The melting season is underway (although this year the sea ice extent has increased a bit in the last few days despite that polynya in the Weddell Sea that apparently indicates up-welling of major ocean heat from the depths ).

So I've been having a look at extent loss from max to min over the satellite record.

The main result is how small the variation from the average melt has been over the years. A maximum of +5% in 2005-06 and a minimum of -3% in 2007-08.

Whoops - error in table corrected

The second result is that the average melt in the last 10 years would result in a new record minimum extent in Feb/Mar 2018.

BUT I make no prediction - merely present the past for your edification.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on October 04, 2017, 04:19:46 PM
Update of the NSIDC NT graphics.

2017 still has the lowest maximums of all years. Extent has not moved very much in the last few weeks, but area seems now definitively going south (and is now the lowest for the date).
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 04, 2017, 04:42:45 PM
Wipneus'  graph on area shows significant recent loss as opposed to some extent gain. I was looking at JAXA's sea ice concentration images over recent days and weeks which seemed to also show significant loss of solidity over much of the sea ice.
The Antarctic could be the place to watch this month?
Title: Re: Sea Ice Extent around Antarctica
Post by: Tigertown on October 04, 2017, 07:52:40 PM
Most likely, the recent gains in extent were from dispersion and not much from re-freezing. When the extent starts to fall, it will probably move fast.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on October 06, 2017, 05:55:34 PM
NSIDC extent increased +42k today. It is now only 38k below the 1986 (lowest maximum before 2017) annual maximum. Area is still safe: over +500k distance from the 1986 max.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on October 07, 2017, 05:14:15 PM
NSIDC extent on 6th Oct measured a remarkable 17.999996M. First time that five nines appeared in the extent or area data, Arctic or Antarctic.

It still is 27k below 1986 annual maximum.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on October 09, 2017, 03:33:47 PM
NSIDC extent went up +73k to 18.060M, highest value in 2017. Higher than the 1986 max.

So from an early maximum date, 2017 will now be among the latest ones. Next lowest maximum is held by 2002 at 18.116M (9-9-2002).

Area is still safely staying at the lowest maximum.
Title: Re: Sea Ice Extent around Antarctica
Post by: Feeltheburn on October 13, 2017, 06:24:01 PM
Antarctic sea ice extent (JAXA data) reached a maximum of 17.640 million km2 on 25th August. 7 days later it is 125,000 km2 less at 17.515 million km2. In this period the average gain is 250,000 km2.
However, there are often big ups and downs in September, so a surprise may be in store either way, especially given average date of maximum is more like around the 20th September. If 25th August ends up as the date of maximum (2016 was on 29th August) - good heavens.

So, like a fool I will prognosticate a maximum extent of less than 18 million km2.

The extent losses reversed themselves and have now reached a season high on October 9, 2017. See Wipneus graph below. Predicting ice is a dangerous bet sometimes!
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on October 13, 2017, 07:13:55 PM
According to NSIDC data, it seems like the seasonal maximum was reached at October 11 and possible also virtually tied by October 12. If October 12 is going to be a confirmed date by NSIDC it will be a tie of the absolutely latest date a seasonal maximum has occurred around Antarctica.

The other year this happened was 2002. If you compare 2002 with 2017 from the middle of May or so, you will see a remarkable similarity between these two years.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on October 13, 2017, 07:40:21 PM
According to NSIDC data, it seems like the seasonal maximum was reached at October 11 and possible also virtually tied by October 12. If October 12 is going to be a confirmed date by NSIDC it will be a tie of the absolutely latest date a seasonal maximum has occurred around Antarctica.

The other year this happened was 2002. If you compare 2002 with 2017 from the middle of May or so, you will see a remarkable similarity between these two years.

this post has been deleted because it was wrong (badly researched and not verified as correctly pointed out by LMV below) :-[
Title: Re: Sea Ice Extent around Antarctica
Post by: Lord M Vader on October 13, 2017, 10:44:00 PM
Mag: I'm sorry, but where do you get the number 2 Mn from? From June 1 and onward the biggest difference is only 500K.
Title: Re: Sea Ice Extent around Antarctica
Post by: magnamentis on October 14, 2017, 12:05:10 AM
i'm not one who has to be sorry, shame on me, i mixed something up and looked in an entirely wrong graph, even had a feeling but was to lazy to go back and verify, double fail  :-[

you are and were totally right, embarrasing but it happend ;)

thanks for correcting, ill alter the post now
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 15, 2017, 02:47:43 PM
JAXA DATA
Jaxa is having a day off but I show the graph below to illustrate the degree to which extent loss in the next month must exceed the average to match 2016.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on October 15, 2017, 11:50:02 PM
Things are getting hot and almost 5°C anomaly forecasted
Title: Re: Sea Ice Extent around Antarctica
Post by: kiwichick16 on October 17, 2017, 10:28:26 PM
looks like parts of the Ross Ice Sheet are close to + 20 degrees
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on October 18, 2017, 03:37:47 PM
Update of NSIDC NT extent and area graphs.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 18, 2017, 04:20:16 PM
Things are getting hot and almost 5°C anomaly forecasted
While SST anomalies are high on the Antarctic continent itself they are mostly zero to -ve offshore, i.e. where the sea ice is. This may be why sea ice extent loss is still moderate.
Title: Re: Sea Ice Extent around Antarctica
Post by: miki on October 18, 2017, 05:22:44 PM
Things are getting hot and almost 5°C anomaly forecasted
While SST anomalies are high on the Antarctic continent itself they are mostly zero to -ve offshore, i.e. where the sea ice is. This may be why sea ice extent loss is still moderate.

Can that also be because ice is melting over there, causing the temperature to cool and the anomalies to zero?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 21, 2017, 04:14:48 PM
JAXA DATA
So far extent loss has been very slow - just 0.46 million km2 to 20th October, compared with 1.29 million km2 last year and the 10 year average of 0.84 million km2. As a result extent on 20th October is nearly 0.4 million km2 greater than on that date in 2016.
If extent loss fails to markedly accelerate soon, it is likely that 2017 extent will merge into the pack.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 24, 2017, 01:02:41 PM
JAXA DATA

herewith table and graph re extent loss to date (23rd October). Very slow melt continues.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on October 27, 2017, 08:29:06 AM
Updating NSIDC NT extent and area: the way down has not really been found yet.

Unfortunately posting any graph gives:

Your attachment has failed security checks and cannot be uploaded. Please consult the forum administrator.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on October 27, 2017, 03:13:51 PM
Well, today both graphs seem to be accepted. Same comment: no on the way down yet.
Title: Re: Sea Ice Extent around Antarctica
Post by: steve s on October 27, 2017, 11:24:53 PM
Is there any time series tracking ice thickness or volume?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 28, 2017, 02:58:20 PM
Is there any time series tracking ice thickness or volume?
I have not found one. Perhaps 'tis because most Antarctic sea ice is First year, i.e. melts every year.

JAXA DATA

So far the story this year (to 27th October) is of very low extent loss since maximum, being 0.61 million km2 as opposed to the 10 year average of 1.19 million km2. This is the opposite of 2016, which had an extent loss of 1.8 million km2 by this date.
Only 2008-09 had a lower extent loss (0.47 million km2) at this date.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on October 31, 2017, 03:36:47 PM
Has the Antarctic melting season got properly underway at last?
We are almost at the point when 2016 melting went doo-lally. What will happen this year?
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on November 05, 2017, 03:20:17 PM
JAXA DATA

the Antarctic melting season HAS got properly underway at last, but whether it will match 2016 is very much an open question.
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on November 06, 2017, 12:49:13 PM
JAXA DATA

On this date one year ago Antarctic sea ice extent became the lowest in the satellite record. At the moment this is not being repeated.

On 6th October 2017 extent exceeded 2016 extent by 51,815 km2. That difference has increased to 707,854 km2 (4.4%). (5th November extent is 16,696,169 km2).
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on November 06, 2017, 04:45:09 PM
Update of the NSIDC NT extent and area graphs. The way down has been found, area is among the lowest years again.
Title: Re: Sea Ice Extent around Antarctica
Post by: Pavel on November 10, 2017, 08:40:56 AM
Hycom thickness product is now available for Antarctica
(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/antarcictn_nowcast_anim30d.gif)
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on November 10, 2017, 01:28:35 PM
Hycom thickness product is now available for Antarctica
Gosh - that is rather good - thick ice and strong northward drift  along Larsen C and then North East out of the Weddel Sea? Due to Weddell Sea Gyre posted by AbruptSLR?
Meanwhile:-
JAXA DATA

Average extent loss per day 125K km2 for the last 6 days. But not as much as 2016.

Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on November 14, 2017, 02:10:23 PM
JAXA DATA

Antarctic sea ice extent continues to decline at well above average but below that of 2016. The table below shows the variation compared with the previous 3 years. Extent at  15,510,324 km2 is some 270,000 less than the low year of 2002, but to put this in perspective, this is about 2 days average extent loss at this time of year.
Title: Re: Sea Ice Extent around Antarctica
Post by: Wipneus on November 14, 2017, 05:03:59 PM
Updating the NSIDC NT extent and area graphs. Both are second lowest for the day of year (but far above 2016 still).
Title: Re: Sea Ice Extent around Antarctica
Post by: gerontocrat on November 20, 2017, 03:32:58 PM
JAXA DATA as at 19 Nov 2017

Extent loss is still proceeding at well above average, but less than in 2016, which was just under 1.1 million km2 less at this date.
Title: Re: Sea Ice Extent around Antarctica
Post by: Buddy on November 20, 2017, 03:44:41 PM
Tough to catch up to 2016's very early start.  But angle of descent is now equal to or even slightly greater than 2016.  PDS (pretty damn steep)....😳