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Messages - Glen Koehler

Pages: [1] 2
1
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 26, 2020, 09:36:56 PM »
Quote from: philopek on February 26, 2020, 03:25:18 PM
Quote from: Hefaistos on February 26, 2020, 12:46:45 PM
hi.
I live on 60N in Scandinavia and this has been the 'new normal'  winter for a decade at least. Our winters are getting much shorter as a result.
<snip>

A few remarks:

- you may not feel the punch in cold air-masses and the frequent inversions where the air at ground level and close to it is colder than at some higher altitudes.

- nevertheless the energy that can be measured, even at low sun-angles IS SIGNIFICANT.
. In fact, compared to zero it's even huge while not TOP-Level of course.

- Said energy, meeting darker surfaces, makes a "HUGE" difference. Not only in absorbing
. energy but also by quicker melting of the remaining and/or existing snow cover.
<snip>

+1 to your +1;

I think to put it in context Hefaistos, you need to think not necessarily about what's happening now, but where conditions will be in 3-4 weeks.

What is happening is setup, much like how much running room you have leading up to a broad jump.  By losing snow this early, and picking up what are modest but still significant amounts of solar energy means that considerably more energy will
(1) ... be captured directly at Arctic latitudes
(2) ... be available early in the melt season
(3) ... not be required for/buffered by local phase change (e.g. melting snow locally)
(4) ... indirectly permit more transport of heat to the Arctic from lower latitudes. (primarily via
          increased moisture)

We are not necessarily increasing the amount of energy available, but we are extending the melt season by way of making it possible to capture that energy earlier.

Another way of looking at it is to think about melt rate at the peak of the season.  The difference between 2012 and pretty much every year starting with 2016 is 7-10 days of peak melt.  That's the razor's edge we are on.

The earlier the heat can be made available is that much more opportunity for us to have those peak melt days, and regardless (within reason) of the starting ice conditions that makes a 2012 event more likely.

If we have another "perfect" melt season like 2012, it means blowing past that year into the realm of sub-3 million km2 extent.  *Well* past.

We've been rolling dice with this for the best part of a decade.  Each additional year has loaded the dice progressively in favor of melt.

That's why lots of bare ground at high latitudes is concerning, even before the equinox.

2
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: February 26, 2020, 09:05:22 PM »
ascat, north of greenland, day51-56, forward and back. Fram/FJL gap intake drift extends as far as the Lomonosov ridge (vertical line to left of pole hole), temporarily.
Ice slips more easily on higher salinity water? or more turbulence along the ridge?

added an avi of ascat, lomonosov ridge area, 2010-2019 for those few that would like to see if there is a similar previous occurrence since 2010. mp4 quality after conversion and compression not really good enough.

3
Arctic sea ice / Re: What's new in the Arctic ?
« on: February 24, 2020, 06:42:42 AM »
Interesting article published by the Scripps institute about methane in permafrost.

https://scripps.ucsd.edu/news/climate-destabilization-unlikely-cause-methane-burp

Quote
“Anthropogenic methane emissions currently are larger than wetland emissions by a factor of about two, and our data show that we don’t need to be as concerned about large methane releases from old carbon reservoirs in response to future warming,” said Petrenko.  “Instead we should be more concerned about the methane that is being released from human activities now.”

4
Arctic sea ice / Re: Atmospheric connections, structure, and long range weather forecasting
« on: February 20, 2020, 03:49:23 PM »
I also noticed that ever since the Bering/chukchi region "joined the fun", NH midlatitude winters are milder. I compared those winters (since 2004) that had very low ice cover, to those that had high ice cover in the Chukchi/Bering region (on 12/01 each year) - eyeballing the NSIDC sea ice spatial comparison tool (http://nsidc.org/arcticseaicenews/sea-ice-comparison-tool/).
High ice years: 2004,5,8,9,10,11,12,13
Low ice years:2006,7, 2014....2019
In my country the "high years' " average winter temp is 1,4 C while the low years' average winter temp is 3,4 C !!!!
So, it seems that truly, the Bering/chukchi counterbalances the Barents, and the PV behaves better.
The conclusion seems to be that NH winters should by and large be mild going forward with a bigger chance of cold winters when the Chukchi ices over early and/or the Barents is very much ice free.

5
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 14, 2020, 11:09:56 AM »
JAXA ARCTIC SEA ICE EXTENT 13,903,299 km2（February 13, 2020）
Postscript - the Perils of Projections[/b]

I attach a table of the daily change of sea ice extent in February in recent years. Ups and downs like a demented yo-yo. It is the same in March.

Thus the plume of forward projections looks like the data came from a random number generator.

6
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 13, 2020, 11:38:05 AM »
And this is happening with a polar vortex on steroids and the Arctic Oscillation in an all-time, record-breaking maximum. What gives? Textbook says the Arctic should be very cold and the ice pack  expanding.

7
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 12, 2020, 11:43:13 AM »
 ^^ yes .. take a look at last year for example .. the ice leaving Fram or ridging must be replaced . This is where it mostly happens to happen .. b.c.

8
Arctic sea ice / Re: Gulf Stream stall
« on: February 08, 2020, 04:53:38 PM »
https://phys.org/news/2020-02-arctic-ice-ocean-currents.html

9
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 07, 2020, 09:24:38 PM »
I took the monthly extent value for January 2020 and added it into my long-term plot where I calculate the anomalies from 1979 up to now.
The average January extent is now 14,25 M km². January 2020 had an average extent of 13,65 M km², which is 0,60 M km² less than that average.
The higher than average extent gains in this month pushed the actual value well above the red long term linear trend line by 1,09 M km² (calculated from the linear trend line this January should have been at 13,16 M km²).
The slope of the linear trend line has thus decreased by two digits (-0,0558 instead of -0,0560).

See attached graph.

10
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: February 07, 2020, 09:14:55 PM »
It is time for the monthly update of my extrapolation when the extent [Extent], volume [Volumen], thickness [Dicke] and area [Fläche] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one almost constantly resulting in earlier times (valid for volume, area and thickness, not for extent in the winter months). The January value now includes 2020.
Extent, area and volume for January 2020 lie well above the long term trend lines whereas thickness is only slightly above it. The "BOE numbers" increased by averaged 8 years (extent) and 2 years (volume) whereas the "BOE number" for thickness has decreased by 3 years compared to January 2019.
The order (earlier → later BOE) generally is volume < thickness < area < extent.

Please note that this is not a forecast but a trend!
See attached table. stg = slope.

11
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 07, 2020, 03:01:08 PM »
Quote from: Lord M Vader on February 07, 2020, 05:41:11 AM
Juan C: which are the other years next to 2004? I.e the years at place 16-20.

12
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 06, 2020, 04:45:41 PM »
Quote from: Pavel on February 06, 2020, 03:14:49 PM
Quote from: weatherdude88 on February 06, 2020, 01:13:45 PM

There has been significant focus on the lack of snow extent cover, at lower latitude and easier to melt regions, even though we have near record snow/ice volume in the more difficult to melt regions.
In february and march the lower latitudes are more important in terms of albedo while the higher latitudes snow cover become important in May/June. We have now extra heat absorbing in 3 mln sq km of land

True, but how relevant is it to Arctic sea ice.  Much if the lower latitude snow cover can be correlated with temperatures (melt is significant as temperatures rise above freezing).  Using the average January temperature in Chicago (using other U.S. cities will yield comparable results), since 1998 (the year the ice started its precipitous decline), there is no correlation with Arctic sea ice.  The trend line is completely flat.  The warmest January averages (prior to this year) were 2006, 2002, 2012, 1998, and 2017 respectively. 2012 is a noteworthy year, but the others are unremarkable.  Two resulted in declining sea ice at minimum, while two yielded increasing sea ice.  The warmest year, 2006, was one of the highest year-over-year sea ice gains.  The coldest years were 2014, 2009, 2004, 2011, and 2019 respectively. 

One could argue that this analysis of increased temperatures and decreased snow cover only covers the lower latitudes of North America.  Interestingly enough, the warmest January in Chicago (2006) corresponded to the second coldest January in Fairbanks, Alaska, and the coldest (2014) was the second warmest.

13
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 04, 2020, 08:11:40 PM »
Quote from: Glen Koehler on February 04, 2020, 05:29:09 PM
Quote from: grixm on February 01, 2020, 09:15:14 AM
Therefore, I experimented with instead normalizing the years to their predicted average extent from a linear regression of all the years.
Quote from: Steven on February 01, 2020, 07:16:59 PM
Your method is skewed by the fact that the long-term extent losses are happening more rapidly in September than in January/February/March.

September extent in the last few years is about 40% lower than in the 1980s, whereas March extent has decreased by only 10%.  So your "normalized" March extent has an upward trend over the last few decades, whereas the normalized September extent has a downward trend.  So it's not surprising that you get a negative correlation between them.  But that correlation is spurious.

A more meaningful method is to detrend the data (see e.g. here for some background on detrending).  It turns out that the correlation between the detrended March extent and the detrended September extent is very weak: the correlation coefficient is  -0.029.

    Many thanks to grixm and Steven et al. for wrestling with the numbers.  It looks like the jury is still out on this one.  While counter-intuitve [more Extent early leads to less 8 months later (Jan-Sept), 7 (Feb-Sept.), or 6 March-Sept.)], the insulating ice theory at least sounds plausible. 
[..]

I normalized the months to the trend of its month alone, instead of to the whole year, like pointed out. And it seems Steven is correct. The correlation is gone..




14
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 04, 2020, 01:43:49 PM »
Quote from: Observer2019 on February 04, 2020, 10:00:59 AM
Quote from: gandul on February 04, 2020, 05:52:40 AM
In other words, the 17 years with lowest sea ice extent for the date are among the first 20 years of the 21st Century. A clear perspective of long-term trend of global warming, thanks weatherdude.

Take into account that this is all based on data from 1979 and on. There is no real data from before ( there are some very bad satellite pictures from 1975'ish). Before that there is reported anecdotal data from explorers and locals that in some cases point to low arctic ice.

You might want to look at this 1947 report from DMI on the state of the Arctic Sea Ice.

As you probably know, 1947 was at close height of the mid-19th century warm peak. The August extent in the DMI report is of a similar magnitude to what the winter extent is likely to be this year, so between 2 and 3 times more than this decade.

So any anectodal evidence for low sea ice extent from before 1979 will have to be taken with a ton of salt. Or rather, tied to a rock and thrown overboard. Any and all documentation from before 1979 shows greater sea ice extent than what we are seeing this last decade.

This paper from 2001 shows an estimate for the 20th century. August minimum in 1947 would have been around 12 million km2.

And another paper for 2009 seems to agree roughly, taking the estimate back to 1880, which may well have been the maximum sea ice extent since the last ice age.

Having said that, apparently we have to go at least back to around 1200 CE to see extent similar to what we have been seeing in the last decade.

15
Arctic sea ice / Re: Global sea ice area and extent data
« on: February 04, 2020, 12:29:19 PM »
JAXA GLOBAL SEA ICE EXTENT :  16,943,034 km2 as at 3 February 2020

3 days ago, I wrote..
Recently, mostly above average Arctic sea ice extent daily gains, and mostly below average Antarctic sea ice extent daily loss leading to recent days of extent gain. It is therefore possible that minimum was reached on the 29 January at sea ice extent of 17,046,068 km2, i.e 2 weeks earlier than the average of the last 10 years.

I was wrong. In the last 3 days Arctic Sea Ice gain has stalled, and Antarctic Sea Ice loss a bit above average. Predictions are a mug's game.

- On this day extent is 9th lowest in the satellite record since 1979,
- Extent LOSS on this day 55 k, 35 k MORE THAN the last 10 years' average loss of 20 k,
- Extent loss to date 7.66 million km2, 1.15 million (13.1%) less than the 10 year average of 8.81 million km2 by this day.
- Extent is 0.68 million km2 greater than 2006,
- Extent is 1.19 million km2 greater than 2017,
- Extent is 1.06 million km2 greater than 2018,
- Extent is 0.65 million km2 greater than 2019,
- Extent is just 9 k km2 greater than the 2010's average,

- 96.7% of the average ice loss of the season done, with on average 9 days to the average minimum date of 12 Feb.

The Perils of Projections

Average melt from this date would produce a minimum of 16.64 million km2, 1.09 million more than the record low in early 2018.
____________________________________________________________________

16
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 04, 2020, 10:48:55 AM »
"The coldest January on Kodiak is the forerunner of the big summer ice loss? Top 10 includes January 2007 and 2012."

I think there might be some truth to that. Alaska is cold during the winter and Europe/lower 48 US is warm when the polar vortex is well behaved and no "cold-spills" reach them. Due to this there is usually little snowcover in NH midlatitudes so when spring comes they should warm up fast. This could of course lead to a fast meltout of the periphery in the Arctic which - given good weather - would lead to fast ice loss especially as there is not much old ice nowadays.

There are many ifs though...but I think we have a good chance of seeing some "fireworks" during this summer in the Arctic

17
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 04, 2020, 05:52:40 AM »
Quote from: weatherdude88 on February 03, 2020, 06:48:27 PM
For 2.2.2020, the NSIDC northern hemisphere sea ice extent value is 14.42 millions of square kilometers. This is an increase of 116,000 square kilometers from the previous day.

NSIDC sea ice extent is in 15th place for the date. 2020 has more sea ice extent than 2004, 2005, 2006, 2007, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, and 2019 for the date.

The next 4 closest years are 2009, 2008,...

In other words, the 17 years with lowest sea ice extent for the date are among the first 20 years of the 21st Century. A clear perspective of long-term trend of global warming, thanks weatherdude.

18
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: February 02, 2020, 09:43:30 PM »
2019 was 2nd lowest minimum in the satellite record, and freezing was very late.

Did it make much difference ? Out of the cupboard comes my once a year graphs of the number of days when ice area for each sea was less than 15% of total area of each sea (or less than the 1980s maximum for seas bounded by open ocean, e.g. the Bering)

Some seas, e.g. the East Siberian Sea, had record numbers of days of very low or zero ice-free conditions. Others did not. There are 6 graphs, so 2 posts.



19
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: February 01, 2020, 01:53:35 PM »
JAXA ARCTIC SEA ICE EXTENT January Average

The first graph shows the simple average of JAXA Arctic Sea Ice daily extents for January, and the deviation from the linear trend.

The January 2020 deviation from the trend is the highest above the trend in the satellite record since 1979.

The table shows the current extent compared with previous year's maxima. Not far to go to pass by several of the previous years' maxima. As the days go by it will be interesting to see how many previous year's maxima will be exceeded and how early.

20
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 01, 2020, 09:15:14 AM »
Overnight I realized that my graphs has a big flaw, the fact that the years are normalized with themselves can induce a lot of autocorrelation. For example, if it is the case that a low september minimum is completely random, that would still increase the ratio of normalized winter extent vs normalized september extent, because the low september extent would drag the average for the whole year down, thus increasing the normalized winter extent. Furthermore, since calculating the normalized extent requires knowledge of the average for the whole year, it is not possible to predict anything with it beforehand.

Therefore, I experimented with instead normalizing the years to their predicted average extent from a linear regression of all the years. Now, it should be truly neutral, and also you can make predictions. Unfortunately, doing this does reduce the correlation a lot, but it is still there.

Now, we can make  a prediction for 2020 based on the january value. The high extent compared to the ever-decreasing trend makes this year stand out a lot, the normalized january extent is an all-time high: 1.322. See the red area on the january graph. Will this mean the september extent  will be very low like the graph suggests? Or does it mean the correlation will break down? If we trust the graph naively, the expected normalized september minimum average for this year is 0.42, which is 4.30 Mkm^2 (which is third lowest of all time, behind 2012 and barely 2007), with a lower uncertainty bound of ~2.97 Mkm^2 and a high bound of ~5.33 Mkm^2.




21
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 31, 2020, 10:39:56 PM »
Here I have plotted the normalized average extents in january, februrary and march, compared to september. Normalized meaning the value divided by the average value for the whole year. This means that the long-term trend of general melting is removed.

There seems to indeed be a strong correlation of high extent early season = low extent late season, for all three months graphed.






22
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 29, 2020, 10:26:15 AM »
Quote from: Glen Koehler on January 29, 2020, 12:12:04 AM
Is there some formula for translating the thickness of a single chunk of ASI ice into a relative or absolute melt resistance value?

Not that I'm aware of. Melting is a much messier process than freezing.

A "Great Arctic Cyclone" in August seems to have a significant effect on Arctic sea ice melt for example!

https://neven1.typepad.com/blog/2012/08/arctic-summer-storm-open-thread.html

23
Arctic sea ice / Re: Does El Niño affect Arctic sea ice?
« on: January 28, 2020, 06:01:43 PM »
Research Links Sea Ice Retreat With Tropical Phenomena, Including a New Kind of El Nino
https://phys.org/news/2020-01-links-sea-ice-retreat-tropical.html

Two researchers present evidence today in the journal Proceedings of the National Academy of Sciences that the accelerating melt of Arctic sea ice is linked to weather patterns near the equator in the Pacific Ocean.

the researchers said there is strong evidence that the ice melt sets a chain of events in motion that sends cold air equatorward in the upper atmosphere. The two used computer analysis of historical data to identify which atmospheric phenomena also change as Arctic ice diminishes, as it has steadily since 1999. Among the variables that seemed to move in lockstep with ice melt were intensifying trade winds at the equator in the Central Pacific Ocean. The study marks the first time that researchers have looked at both world regions together in this context.

... Though many researchers had thought that air originating in the Arctic couldn't make it to the equator, Kennel and Yulaeva said their work suggests it does.

One consequence is that the nature of El Niño storms changes. Classical El Niños feature build-ups of warm water at the eastern end of the Pacific Ocean off South America. Kennel and Yulaeva's analyses indicate that El Niños starting in the Central Pacific Ocean are the ones that respond to the arrival of Arctic air near the equator. Kennel suggested that since so much of California's rain comes from atmospheric river storms that develop in the Central Pacific, the Arctic-Tropics connection merits further study.

Open Access: Charles F. Kennel et al. Influence of Arctic sea-ice variability on Pacific trade winds, Proceedings of the National Academy of Sciences (2020).

24
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 28, 2020, 11:46:16 AM »
Quote from: oren on January 28, 2020, 11:34:02 AM
The extra volume this year is in the Barents (and the Kara)

I've done my due diligence this morning (UTC), and there's still a total absence of any ice >= 4m thick to be seen on the most recent CS2/SMOS reanalysis. Chapter and verse over at:

http://GreatWhiteCon.info/2020/01/wheres-the-thickest-arctic-sea-ice-gone/

including this (hopefully?) explanatory video:



Quote
Not unexpectedly that meant that ice in the northern Barents Sea was slow to melt out in the summer of 2019, whilst after a fast start the melt in the Beaufort Sea suffered a “brief hiatus” in June before ultimately melting out almost completely.

25
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 28, 2020, 11:34:02 AM »
Quote from: Glen Koehler on January 28, 2020, 01:54:24 AM
Jim -
     Both Thickness and Extent seem to be much less in 2020 than 2019 in those images.  But the December PIOMAS Volume data show Dec 31 2019 only about 3% below Dec 31 2018.
https://forum.arctic-sea-ice.net/index.php/topic,119.msg242997.html#msg242997

 The dramatic difference in Thickness and Extent in those maps look like a lot more than a 3% Volume decline. 

    Or is the January PIOMAS going to deliver a bombshell?  But that also seems unlikely given robust Extent gains in recent  weeks.  And there has only been 19 days between Dec 31, 2019 and the Jan. 19, 2020 graph. 

   CryoSat vs. PIOMAS difference doesn't explain it either, since both images are CryoSat.  Something is not lining up.   The only explanation I can think of is a re-calibration of CryoSat.  But I don't have any info pointing to that. 

   Bottom line:  the 2019 to 2020 difference in those maps is too huge to believe.  If it is real then it looks the Arctic is going to get blitzed in the 2020 melt season.

    Or am I missing/misinterpreting something?
The extra volume this year is in the Barents (and the Kara), as can be seen in Jim's image based on Cryosat/SMOS, as well as in Wipneus' diff map based on PIOMAS. The missing volume this year is next to the CAA, again seen both in Cryosat/SMOS data and in PIOMAS. These two sources are very different (one is mostly measured, one is mostly modeled), but are in general agreement. I do not expect a January bombshell, but the melting season could become interesting should there be an early meltout of the Barents.

26
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 28, 2020, 01:33:12 AM »
In the absence of the mid January PIOMAS update I'm being moaned at over at "Climate Etc.".

Hence please feel free to compare and contrast:

27
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: January 22, 2020, 03:24:39 PM »
Quote from: Tom_Mazanec on January 22, 2020, 01:28:32 PM
Thanks, pleun.
Should have looked closer.
Wow, the date is all the way from Feb 15 to 31 Mar. Why the wide variation, different air masses passing over the Pole? I don't recall, does the thaw have such a wide range of ending dates?
At maximum sea ice extent /area change is of thin ice in peripheral seas.  Thus a small variation in winds / temperatures can halt or increase sea ice extent enough for an early or late maximum date.

Note that for a month or so after extent/area maximum, the Arctic Ocean is damn cold, and ice thickness continues to increase at a greater pace than ice is lost in the periphery. Hence ice VOLUME maximum is in April.

28
Arctic sea ice / Re: Atmospheric connections, structure, and long range weather forecasting
« on: January 22, 2020, 09:50:56 AM »
Atmospheric superrotation is the endgame for the Earth we recognize.  As such, it's also probably decades off.  We're not at an instantaneous climate change moment, just abrupt.

What's interesting is that after all that time of low winds, it has corked positive with the greatest acceleration we have ever seen.

The atmospheres of Venus and Titan superrotate those planets.  https://journals.ametsoc.org/doi/full/10.1175/JAS-D-15-0030.1

It's expected that Earth, too, will abruptly transition to a superrotating atmosphere.  Angular momentum at zero essentially means that the planet's atmosphere is static relative to the surface with no prograde or retrograde net rotation.  It has no angular momentum to deposit or absorb.  You could say that any time vertical and zonal integral of relative AAM anomaly is positive, the atmosphere is rotating faster than the Earth, but this is not the same as the definition of superrotation applied to other planets.

In order to truly superrotate, you'd have to have the QBO westerly and endless convective plumes from the Tropics lined up just right.  At some point, when that happens, this planet should exhibit a bimodal stability and flip into the true hothouse mode where equatorial temperature differences East to West are eliminated because the Rossby waves flooding poleward introduce enough Westerly momentum equatorward that the Equatorial Easterly winds are reversed.  I was reading that this flip to superrotation occurs with Equatorial ocean temperatures around +33C.  That is... if the stratocumulus deck doesn't evaporate first.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008PA001652

https://journals.ametsoc.org/doi/abs/10.1175/JAS-D-19-0089.1

Either way, the completely Westerly tropical surface winds lately yielded an atmospheric acceleration faster than has ever before been observed.  This would be fascinating if it were happening on Mars.

29
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: January 21, 2020, 10:38:34 PM »
update of mercator 34m salinity, sep2017-jan2020
edit: forgot scale

30
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 15, 2020, 04:13:56 AM »
Hi all,

As an amateur observer, I've paid quite close attention to the Arctic this season, so maybe others can elaborate on some things i've noticed.

1) Cyclones in the North Atlantic. For the last 2-3 weeks, deep developing cyclones have been a constant. A couple have reached 940mbar, real monsters. Pulling right down the Greenland current, and undoubtedly affecting Arctic inflow with Atlantic water. Sidenote: I have to imagine these winds and 15m waves hitting Greenland, probably has some affect on underwater melting via mixing?
 
https://www.severe-weather.eu/recent-events/north-atlantic-onroll-intense-extra-tropical-cyclones-mk/

2) Incoming collapse of the Beaufort High. The typical anti-cyclonic gyre wind and pressure is getting increasingly encroached by cyclonic low-pressure. I don't know enough about this, but the research i've seen has insinuated the effect on ice formation in the Pacific ice, Beaufort/Chukchi/ESS, but can also affect the CAA.

Zack Labe actually had a picture in the melting season, that showed the significant meridional anomaly right up the Bering for the year (pic link right below). I'm guessing it was the high pressures from the Pacific contrasting with the Aleutian lows. I haven't watched enough years for precedent data, but there's also been some cyclone formation closer to the land masses on the Pacific this winter season. That can advect some real warmth.

https://pbs.twimg.com/media/EB5d4YuU4AAgalW.jpg

And just my opinion, but baroclinity and cyclone formation + the low pressure patterns they arise from (and contrasting high pressures) with baroclinity differences seem like they may be understated in the grand scheme of things. We've seen the effect in late summer, the effect it can have over the Barents, and the water flow + advection they can perform, which could serve to only exacerbate the situation. Long term, anyway.

The US has also been getting hit by severe weather, and more coming the next 5-7 days. So if you're interested in snow extent, snow depth, etc, may want to check on that the next week. There was also a minor chance of a vortex disruption, but who knows. The last few have occurred around early February for US weather, I believe.

https://www.severe-weather.eu/global-weather/15-day-outlook-ridge-cold-usa-europe-fa/

31
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 14, 2020, 02:14:46 PM »
Those ponds, together with "Last weeks 7-day hindsight means GIF (anomalies)" posted by Blumencraft just few posts above, confirm one big suspicion i had for this freezing season: namely, the huge winter mode shift for Arctic and subarctic regions. Which shift is more heat and moisture in the system causing more clouds remaining for much of the winter, which clouds then dramatically slow down winter-time heat loss from both the surface and lower athmosphere. Which slowing further massively extends duration and scale of "thickly clouded" areas - a runaway process.

Obviously, any prolonged periods of massively dwarfed heat-loss process in Arctic and adjucent regions - will have significant impact on following melting season(s), but there is yet one much more serious implication: the "albedo connection" as one may perhaps call it. The warmer things are, the less places are snow-covered by the time insolation starts to be a thing again (and the less snowcover's thickness / brightness is there in places which still retain some snowcover, too). Just like ArcticMelt2 just mentioned: "when the sun comes up", which for sub-arctic regions is already pretty much "now" or "very soon".

Right about now, we have much of the Arctic cloudy (good bye, "polar desert", eh), and even some parts of it - between Iceland and UK/Scandinavia - getting few millimeters of rain. If those cyclones would keep coming same way, then together with seriously positive SST anomalies around Scandinavia and all along US eastern coast - then i wouldn't be surprised to see Atlantic side of the Arctic going blue much much earlier than ever before, later this year.

32
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 14, 2020, 07:32:39 AM »
Quote from: Glen Koehler on January 14, 2020, 02:36:59 AM
Using a preliminary GISS-equivalent temperature for December and filtering out those short-term influences shows 2019 as the warmest year since modern records began.
Ocean temps apparently reached their highest levels yet, according to this article in the Guardian.

2019 shows a marked jump on the year before, also interesting is the apparent change in slope after 1990.


33
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 12, 2020, 06:58:01 PM »
Last weeks ice-drift map, 05th to 11th.

34
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 12, 2020, 05:57:29 PM »
Here the Histogramms:

09.01.2019

09.01.2020


In 2020, SIT above 3m not exists

35
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 12, 2020, 11:43:14 AM »
In other words:

mean thickness at this date:

2019: 1.137332m
2020: 1.000787899m

while extent is nearly the same

36
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 07, 2020, 07:43:17 PM »
gnnng sdlkto vlspto  ;)

37
Arctic sea ice / Re: Latest PIOMAS update (January 2020)
« on: January 06, 2020, 08:51:56 PM »
Quote from: RikW on January 06, 2020, 04:17:19 PM
To me, it appears reasonable stable for the last 8/9 years; Curious why that is the case, is it coincidence? A trend? Mechanics we don't understand yet (okay, that one is at least true ;) )

2010 was when virtually the last of the MYI went, so there haven't been large chunks of thick ice there to be lost since then.

38
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: January 06, 2020, 10:02:15 AM »
Quote from: Random_Weather on January 05, 2020, 09:30:55 AM
With PIOMAS

This one is especially nice. A slight disagreement appears between your index and PIOMAS, as to whether volume is cleaving to the 2011-18 mean. Statistically insignificant, perhaps, but fun nonetheless: red versus grayish blue!

39
Arctic sea ice / Re: Latest PIOMAS update (January 2020)
« on: January 05, 2020, 09:14:07 PM »
If you plot the annual mean value you get a linear (fits quite well) trend line with a slope of -0,305 kkm³ per year, which is roughly close enough to your estimation.

40
Arctic sea ice / Re: Latest PIOMAS update (January 2020)
« on: January 04, 2020, 11:49:34 PM »
Quote
around 1.5km3 per day
My reading of the graph suggests 1,000 km3 per 3 years ~ 1 km3/day or 3,000 km3 per 10 years ~ 1.2 km/year.

41
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 02, 2020, 10:37:32 AM »
https://twitter.com/zlabe

Quote
Standardized anomalies of annual regional #Arctic sea ice extent - now updated through 2019. New record low this year for the Chukchi Sea.

[Data from @NSIDC; Bright blue = maximum year, bright red = minimum year, vertical lines = 2007/2012/2016/2019]



https://twitter.com/AlaskaWx

Quote
The Bering Sea average ice extent for December was second lowest in the 42-year from @NSIDC passive microwave data, only 41% of 1981-2010 average. Good weather now for ice growth but late start sure to reduce thickness. #akwx #Arctic #seaice @Climatologist49 @KNOMnews @KYUKNews


42
Arctic sea ice / Re: "Stupid" Questions :o
« on: December 31, 2019, 12:26:19 AM »
Quote
The contribution of waste heat to the global climate is 0.028 W/m2. In contrast, the contribution from human greenhouse gases is 2.9 W/m2. Greenhouse warming is adding about 100 times more heat to our climate than waste heat.

https://skepticalscience.com/waste-heat-global-warming.htm

200 years at 3% growth gets to nearly 370* current level of waste heat - so 3.7 times current GHG effect, but that is hardly warming the earth to the level of the surface of the sun.

43
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 27, 2019, 06:05:44 PM »
Also to note, as thicker the ice gets, as greater becomes the uncertainy of
the measurement. Here Scatterplot for the Mean of 2011-2018:
SIT= Sea Ice Thickness
SITU=Sea Ice Thickness-Uncertainy



44
Arctic sea ice / Re: The 2019/2020 freezing season
« on: December 25, 2019, 05:00:57 PM »
Deleted thickness up to 2 metres.
2012, 2016, 2019 compared.

http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume/#c23629

45
Arctic sea ice / Re: The 2019/2020 freezing season
« on: December 25, 2019, 04:59:02 PM »
Although sea-ice extent is not the lowest right now, volume appears to be low, and might influence extent to become a low maximum this winter.
2012, 2016, 2019 compared.

http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume/#c23629

46
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: December 24, 2019, 08:40:34 PM »
Because I am bored (crap on the TV), and some of you may be desperate for your JAXA data fix, here is some methadone.

NSIDC ARCTIC SEA ICE EXTENT :-  12,168,920 km2（December 23, 2019）
5 days trailing average data
- Extent gain on this day 80 k, 44 k more than the average gain (of the last 10 years) of 36 k,
- Extent gain in this freezing season to date is 8,016 k, 337k (4.4%) MORE than the average last 10 years gain to date of 7,679 k.
- Extent is 6th lowest in the satellite record,
- Extent is 389 k more than 2016
- Extent is 42 k more than 2018
- Extent is 18 k (0.1%) less than the 2010's average.

- on average 75.9 % of extent gain for the the season done, 79 days on average to maximum.

We are well into the period when usually extent gains slow down

Projections.

Average remaining extent gain in the last 10 years from this date produces a maximum of 14.57 million km2, above the lowest in the satellite record by 0.33 million km2.
____________________________________________________________
Ice Gain Outlook??

Who knows?
____________________________________________________________

47
Arctic sea ice / Re: "Stupid" Questions :o
« on: December 19, 2019, 08:09:30 PM »
Quote from: gerontocrat on December 19, 2019, 07:36:37 PM
Quote from: kassy on December 19, 2019, 07:06:55 PM
No the days were shorter because the planet turned faster.

Bonus question did years exist before calendars?
Stonehenge is a calendar.
Is it? Well as a minimum it shows that they had celendars back then. But I prefer to see Stonehenge as an early silicon based computer running at 1 Hz / annum.

48
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 19, 2019, 02:37:47 PM »
Its also possible to make Sea Ice Snow Mass (SISM) for the arctic: ftp://ftpsrv2.awi.de/sea_ice/product/cryosat2/v2p2/nh/l3c_grid/monthly/

- Use Snow Thickness
- Use Snow Density
- Use NSIDC Extent

You get:


In other words, arround 190-200 Gigatonnes (Gt) Snow Mass every year on arctic sea ice, before melt saison beginns. This is quite stabile, havent though its that low variance

49
Arctic sea ice / Re: Near Real Time Sea Ice Volume
« on: December 18, 2019, 08:00:25 PM »
And perhaps the Scattern Plots for Cyrosat 2 and PIOMAS for 2011 to 2019(april) mon_mean

PIOMAS vs. NRT SIV



Cyrosat2 vs. NRT SIV


No surprise, Correlation must better against Cyrosat2 because its related to it in main fraction, besides the infill from SMOS. Also to note, on higher SIV, products beginn to have larger variances

50
Arctic sea ice / Near Real Time Sea Ice Volume
« on: December 18, 2019, 06:01:09 PM »
Hi,

I build up an Near Real Time Sea Ice Volume (NRT SIV) product based on merged data from SMOS and Cyrosat2. To make it very simple, i decide to use mean sea ice thickness(SIT) and extent(SIE) data from NSIDC, beside this, it would also be possible by grid by grid methode, but since in winter, sea ice concentration (SIC) has not much variance over the domain, its seem unlikely that much differences would occur.

First things first, some Explantion:

SIV:  Daily
SIT:  5 five-day trailing average
SIE:  5 five-day trailing average

Its because of the merged SIT is just in a 5 five-day trailing average format accessible, therefor its also used for SIE and the final product SIV. What does this mean?

SIV(5 Nov): SIT(mean(1-5Nov))*SIE(mean(1-5Nov))


Some Plots:


SIV 2011-2018


NRT SIV vs. Cyrosat2 and PIOMAS (Okt to May)



Open Points for Future:
- Uncertainy-Bads from merged SMOS-Cyrosat2
- Testing other SIE like Uni-Bremen
- Melt-Saison-Model

Data-Source:
ftp://ftpsrv2.awi.de/sea_ice/product/cryosat2_smos/v202/nh/ ->analysis_sea_ice_thickness CS2SMOS merged sea_ice_thicknes
https://nsidc.org/arcticseaicenews/sea-ice-tools/ -> ea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx -> 5 five-day trailing average

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