Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Tigertown on August 13, 2017, 10:38:34 PM

Title: Global sea ice area and extent data
Post by: Tigertown on August 13, 2017, 10:38:34 PM
I think this to be important overall, but especially interesting to watch over the next few months. As the extent around Antarctica sputters trying to making nominal gains, the Arctic chugs away at making losses. By the time the Arctic starts freezing, Antarctica's sea ice will start to drop in extent. If the Arctic freezing season is very slow at all about taking off, Wipneus' global extent chart could see larger gaps developed than ever imagined. I expect it(+related charts) to be a main feature in this thread, though if some one wants to do a JAXA chart, that would be great also.

Here we can see how the global extent starts to tail off over the last couple of years or so. I can't help but wonder what far reaching effects this may have on weather.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 13, 2017, 10:42:15 PM
You really have to look at the year to year chart to get the overall idea, which is why it is the one seen the most.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 14, 2017, 05:51:16 AM
JAXA numbers are in for the 13th and doing the math, roughly, global sea ice extent is down by another 70k plus. Will be interesting to see what the NSIDC numbers show when these come in. Any combination than has greater losses than gains leaves global extent down. Basic math, sure, but we are now in uncharted territory. This can easily continue with minor exceptions for a couple months.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 14, 2017, 04:17:44 PM
Down another 48,000 km2 per NSIDC, leaving the total at 22.347 x 106.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on August 15, 2017, 12:22:13 PM
 JAXA total extent as at 14 Aug is 22.228 million km2, some 0,12 million km2 less than the NSIDC figure, i.e. insignificant.

JAXA data says that on average (2007-2016) remaining Arctic extent loss is 0.2 million km2 greater than Antarctic extent gain. However, the end dates of freezing and melting are unlikely to be the same. This complicates matters. So it is with some trepidation, misgivings and a BEWARE notice that I include the little table below of some possible end of season outcomes.

added a graph
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 15, 2017, 03:59:35 PM
NSIDC is at 22.451 x 106 km2. Up somewhat, and the Arctic sea ice extent actually contributed to the increase.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 16, 2017, 05:36:30 AM
JAXA extents add up to 22,226,175 km2. Down ever so little.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 16, 2017, 02:07:12 PM
NSIDC is up, landing at 22.498 x 106. Antarctic sea ice gained more than the Arctic lost.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 17, 2017, 06:35:33 AM
JAXA lands at 22,225,953 km2, down by a mere 222 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on August 17, 2017, 01:01:17 PM
A Confession:-

Two days ago I posted a table concerning Global Sea Ice Extent with the following warning.

JAXA data says that on average (2007-2016) remaining Arctic extent loss is 0.2 million km2 greater than Antarctic extent gain. However, the end dates of freezing and melting are unlikely to be the same. This complicates matters. So it is with some trepidation, misgivings and a BEWARE notice that I include the little table below of some possible end of season outcomes.

The table was arithmetically correct, but wrong. The methodology of just looking at remaining extent loss and extent gain misses further losses due to the timing of events.
The sequence of events over the next one to 5 weeks seems to be (on average) :-
- arctic extent loss exceeds antarctic extent gain up to the antarctic maximum. Global extent reduces.
- antarctic maximum is reached a few days before arctic minimum meaning further global extent reduction.
- for a few days after arctic minimum (until mid-September) arctic extent gain is still less than antarctic ice loss.
- Arctic freezing gets into high gear and exceeds antarctic extent loss until end-October/Mid-November, at which point Global Sea Ice Extent is at the maximum.
- Then the Antarctic Spring Summer ice extent loss far exceeds arctic winter gain. Global Sea Ice Extent drops.

However, the sequence of events is highly variable. The new table below shows that in the last 10 years the Autumn minimum of global sea ice has happened as early as 23 Aug and as late as the 20 September.

Methinks 'tis the Antarctic that will decide - if 2017 repeats the 2016 low maximum and early rapid extent that made it lowest in the satellite record by November 5th then........
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 17, 2017, 03:22:04 PM
NSIDC numbers are in for the 16th. SIE for the Arctic is 5.310 x 106 and for the Antarctic is 17.171 x 106. Total being 22.481 x 106 km2. Again, down ever so little.

Looking at Antarctic SIE, mentally extrapolating the graph, I look for a peak very early in September.(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 18, 2017, 04:00:01 PM
NSIDC total is 22.483 x 106 km2. JAXA comes in at 22,229,087 km2. Both up just a tad.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 19, 2017, 04:29:26 PM
NSIDC totals to 22.44 x 106 km2 for the 18th. Down 43k.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 20, 2017, 11:37:19 AM
JAXA lands at 22,263,805 km2 for the 19th.

NSIDC numbers total 22.466 km2 for the 19th.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on August 21, 2017, 02:29:02 PM
From JAXA data
Since 14th August Arctic sea ice extent loss has been less than average, while Antarctic extent gain has been greater than average. This has resulted in global extent gains as opposed to "normal" global extent losses. This is obvious in the graph below.

In every year except one, the maximum global extent occurs in late October / early November.
The exception is 2016. The maximum global extent that year was on 7th July, at 23.76 million km2. The Oct/Nov minimum happened on 6th November at 23.64 million km2, within a day or two that Antarctic sea ice extent his a new low in the satellite record.
Is this the future? Are the patterns of global extent and gain changing for good ?

The first table shows some possible outcomes of the end of season (Aug/Sept) minimum.
The second table shows some possible outcomes of the Oct/Nov maximum.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 21, 2017, 02:53:13 PM
NSIDC totals in at 22.514 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 22, 2017, 01:56:47 PM
NSIDC totals for the 21st add up to 22.609 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on August 22, 2017, 02:20:53 PM
From JAXA Data - just when one thought it was all over.

This end-of-season is getting odder and odder.  Arctic extent loss is well below average, Antarctic extent gain well above average.
The average for the last 7 days is a global extent loss of nearly 300,000 km2. This year sees a global extent gain of well over 200,000 km2, i.e over 500,000 variation from the "norm". It is now in the realms of possibility that the Aug/Sep minimum has already happened at 22.2 million km2 on 13 August.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 23, 2017, 03:40:17 PM
NSIDC totals for the 22nd add up to 22.774 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on August 24, 2017, 11:30:43 AM
JAXA data.
Global sea ice extent continues to increase, not decrease.
From 14th August to 23rd August average (2007-2016) extent loss was 350 thousand km2.
In 2017 it has been an extent gain of 300 thousand km2,
i.e. a difference of 650 thousand km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 24, 2017, 03:25:49 PM
NSIDC totals for the 23rd add up to 22.759 x 106 km2. Actually down slightly.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 25, 2017, 03:19:04 PM
NSIDC totals for the 24th add up to 22.694 x 106 km2. Down 65 k.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 26, 2017, 02:10:07 PM
NSIDC totals for the 25th add up to 22.579 x 106 km2. One of those rare occasions of late with both numbers down.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 27, 2017, 02:45:46 PM
NSIDC totals for the 26th add up to 22.543 x 106 km2.  The Antarctic SIE dropped more than the Arctic gained.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on August 27, 2017, 03:14:09 PM
JAXA had an Arctic K35  km2 extent loss + Antarctic extent loss of K25 reducing the  total to 22.427 million km2.
End of season is going to produce differences in daily changes twixt JAXA and NSIDC. Clearer picture after a few days more?
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on August 28, 2017, 02:39:11 PM
Jaxa global extent down 60 on 27th August entirely due to extent loss in the Antarctic.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 28, 2017, 02:56:42 PM
NSIDC SIE is up for the Arctic and down for Antarctica. The total is 22.567 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 29, 2017, 06:35:58 AM
JAXA shows Arctic SIE running in place for the most part and Antarctic SIE starting to take another downturn. Although, it does seems to me that the Arctic sea ice is still thinning in some places like the Beaufort Sea. A couple big drops left there, maybe???(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 29, 2017, 02:38:06 PM
22.608 x 106 km2 is where NSIDC comes in for the 28th. Up a little despite JAXA being down.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 30, 2017, 06:36:16 AM
JAXA totals are in for the 29th at 22,283,729 km2. Down for a couple days in a row now.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 30, 2017, 02:08:06 PM
NSIDC comes in at 22.584 x 106 km2 for the 29th. Down ever so little.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on August 31, 2017, 02:37:14 PM
NSIDC comes in at  22.597 x 106 km2 for the 30th. Up slightly.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 01, 2017, 02:58:58 PM
NSIDC comes in at 22.537 x 106 km2 for the 31st. Down 60k.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 02, 2017, 10:35:40 AM
JAXA comes in at 22,143,633 km2 for Sept. 1st. Down in both hemi's.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 03, 2017, 02:34:03 PM
NSIDC after a couple days of overall drops, lands at 22.353 x 106 km2, for Sept. 2nd.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 04, 2017, 06:34:17 AM
JAXA comes in at 22,114,192 km2 for the 3rd.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 04, 2017, 01:48:20 PM
NSIDC SIE totals are up by 14k to 22.367 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 07, 2017, 02:33:38 PM
After two days of gains the NSIDC totals are back down to 22.448 x 106 km2 for September 6th.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 10, 2017, 05:22:52 PM
NSIDC is at 22.6 x 106 km2 for the 9th, down a little after several increases. Also, a good deal above 2016 at the moment, for the day of year.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 11, 2017, 03:55:44 PM
NSIDC is at 22.558 x 106 km2 for the 10th.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 14, 2017, 05:05:18 PM
NSIDC total SIE  for the globe comes to 22.651 x 106 km2 for the 13th.

JAXA comes in at 22,522,227 km2 for the 13th.

NSIDC shows 22.233 x 106 km2 for 9-13-16. which was about 418,000 less than the current, with about 310,000 of that due to the Arctic's being higher this year. The Antarctic is only about 108,000 above last years extent, and has started dropping; We will see if that continues or not.

I am expecting, through a combination of slow Arctic SIE increase in the near future and normal+ decrease in Antarctica SIE, to see the global extent drop back below 2016 numbers and grow a gap. I think this is what we need to keep an eye on instead of one total alone. Time may prove me wrong, but I really think Wipneus was on to something when starting this chart.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 15, 2017, 02:55:31 PM
NSIDC drops a little to 22.614 x 106 km 2 for the 14th.
Add 8k for the 15th.

JAXA drops to 22,466,783 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on September 16, 2017, 02:20:53 PM
JAXA Data

Oct/Nov maximum in recent years is as follows:-
      2013                2014                 2015                2016
 27,036,458     27,008,379     26,077,710     23,635,821 km2

Extent as at 15 Sept 2017 is  22,469,481 km2. If previous years are any guide (???) staying less than 2016 seems very unlikely (see table below).
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 17, 2017, 04:13:01 PM
NSIDC lands at 22.577 x 106 km2. Antarctic SIE seems to be steady dropping now vs. the Arctic SIE which is fluctuating in an almost stall.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 18, 2017, 05:45:18 AM
For the 17th JAXA comes in at 22,437,011 km2.

22.611 x 106 km2 is the NSIDC totals for the 17th.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: charles_oil on September 18, 2017, 05:50:41 AM

TT - Any chance that on the main graph the last 2 years - 2016 / 2017 could be differentiated a bit as they are almost identical colour / thickness?  Thanks.

Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 18, 2017, 08:11:18 AM

TT - Any chance that on the main graph the last 2 years - 2016 / 2017 could be differentiated a bit as they are almost identical colour / thickness?  Thanks.
Wipneus makes the graph. What I do myself is to zoom in really good at which point you can tell there is more difference in the colors than first appears. Right at the moment, things are kind of clumped up. In a couple of weeks, that should no longer be the case, making it easier to see.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 19, 2017, 03:14:49 PM
For the 18th, JAXA totals come to 22,407,836 km2.

And NSIDC comes in at 22.622 x 106 km2.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: oren on September 19, 2017, 06:06:25 PM
Thanks for the updates. In 2 weeks we will get to the divergence point - with 2016 or with the pack.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 20, 2017, 07:34:42 AM
The JAXA total drops again to 22,369,382 km2.

NSIDC comes in at 22.563 x 106 km2 for the 19th.

@ oren,
 Yeah, just the virtual flatline, if it continues will get us back into record territory in a few days. I am scared to think what it will look like if the Antarctic SIE starts to really fall before the Arctic takes off, which might be a good minute.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on September 20, 2017, 02:45:20 PM
JAXA Data

Oct/Nov maximum in recent years is as follows:-
      2013                2014                 2015                2016
 27,036,458     27,008,379     26,077,710     23,635,821 km2

In recent days Arctic flat, Antarctic declines even though Antarctic SST and temp anomalies are, if anything, -ve.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 22, 2017, 04:10:08 PM
JAXA comes in at 22,392,913 km2 for the 21st.

NSIDC  comes in at 22.615 x 106 km2 for the 21st.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Paddy on September 22, 2017, 09:24:10 PM
It will be interesting to see whether or not we get something similar to last year over the next few months. I'm betting it won't be quite so far from the norm as last year, but what do I know?
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 22, 2017, 10:54:09 PM
It will be interesting to see whether or not we get something similar to last year over the next few months. I'm betting it won't be quite so far from the norm as last year, but what do I know?
  My guessomatic model predicts something along this line;
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: TerryM on September 23, 2017, 12:40:36 AM
Jeez you make nasty guesses!


 I hope we break away from last years path and head back to something not quite as scary. By the end of next month we should have some idea of whether last year was an aberration or the beginning of a whole new global ice regime.


I swing over to Wipneus's charts my get my daily horror fix, but I'd be happy to discover that all had reverted to those halcyon days of 2012, when we didn't worry about the global effects of ice loss, and the resulting changes in albedo.


Terry
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 23, 2017, 01:17:05 AM
TerryM,
Quote
Jeez you make nasty guesses!

Sorry, but the Arctic got off way too easy this summer. The heat has to go somewhere at some point, and I don't expect a great freezing season for the Arctic. And it is just a general guess.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 23, 2017, 03:06:29 PM
NSIDC totals continue the virtual flat-line for the 22nd, adding up to 22.606 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 24, 2017, 05:44:49 AM
JAXA totals come in at 22,388,678 km2 for the 23rd. Down again after a temporary increase.


NSIDC comes in at 22.629 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on September 24, 2017, 02:39:42 PM
Not sure if I can go along with Tigertown's "nasty guesses" when looking at history. But having humiliated myself frequently recently, I make no predictions, merely present what has happened in recent years.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 25, 2017, 05:39:06 AM
@gerontocrat,
I fear that history may be in the making. Thanks for the great info and charts by the way.

JAXA totals are down to 22,312,091 km2 for the 24th.

NSIDC  comes in at 22.555 x 106 km2. Down over one day.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 26, 2017, 04:22:05 PM
For the 25th,

JAXA comes in at 22,330,772 km2.

NSIDC comes in at 22.590 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 27, 2017, 03:09:29 PM
All is up today.

JAXA is at 22,473,632 km2.

NSIDC is at 22.762 x 106 km2.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 28, 2017, 03:05:58 PM
Moving up again, but it's just a matter of for how long?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: TerryM on September 28, 2017, 06:45:26 PM
Moving up again, but it's just a matter of for how long?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)


That said, it's still either the lowest, or the second lowest ever recorded for this date. Area is firmly in place at second lowest, but with a much larger gap between 2nd and 3d.
October will tell an interesting tale.
Terry

Title: Re: Global Sea Ice Extent According to NSIDC
Post by: RikW on September 29, 2017, 03:17:59 PM
Moving up again, but it's just a matter of for how long?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)


That said, it's still either the lowest, or the second lowest ever recorded for this date. Area is firmly in place at second lowest, but with a much larger gap between 2nd and 3d.
October will tell an interesting tale.
Terry

If area will continue the trend of the last couple of days it will in the pack soon.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on September 30, 2017, 02:07:21 PM
What will happen in October ?
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on September 30, 2017, 03:15:35 PM
NSIDC totals for the 29th add up to 22.992 x 106 km2. The last increase being nominal compare to the two prior ones.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 03, 2017, 06:00:25 PM
For Oct. 2nd, NSIDC global SIE totals add up to 23.187 x 106 km2.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 08, 2017, 02:49:35 PM
NSIDC  totals are now at 23.635 x 106 km2 with a recent climbing trend.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 10, 2017, 04:32:43 PM
2017 remains unpredictable. All the home-made models are in the trash can, uh, I mean recycling bin, now.
Up, up, and away!
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Paddy on October 11, 2017, 09:22:49 AM
Not looking like a repeat of last winter then.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 11, 2017, 11:40:38 AM
Antarctica's SIE has stalled again. It should begin to fall soon, being this late in the year. We will see soon how this will affect the global numbers.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 14, 2017, 03:04:39 PM
24.283 x 106 km2 is where NSIDC comes in for the 13th. Down by 14 km2 from the 12th.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on October 15, 2017, 02:58:26 PM
JAXA DATA
Jaxa is having a Sunday off so here is a table as at 13th October. Remaining extent gain in just the next 3 weeks is on average 1.5 million km2, but varies from a mere 0.25 million km2 in the 1980's to over 2 million km2 in 2008.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on October 21, 2017, 04:21:31 PM
JAXA DATA
Average arctic ice extent gain and very slow antarctic ice extent loss has resulted in combined extent as at 20th October of  24,626,679 km2, compared with the absolute maximum last year on 6th November of  23,635,821 km2, i.e. a tad short of 1 million km2 additional extent.

This is likely to increase by up to another 1 million km2 unless something major happens.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 22, 2017, 04:30:50 PM
Things are looking so normal(comparatively) this year; where is the heat going?
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: TerryM on October 22, 2017, 07:16:16 PM
Can I now exhale?
Terry
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 23, 2017, 03:51:25 AM
Can I now exhale?
Terry
Depends on where you are. Here, we are still waiting for summer to end, already a month past the expected calendar timeline. So I don't really think everything is ok. I just think maybe the ice didn't do what what some of us expected, and am beginning to wonder if it will entirely.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: TerryM on October 24, 2017, 01:12:43 AM
Can I now exhale?
Terry
Depends on where you are. Here, we are still waiting for summer to end, already a month past the expected calendar timeline. So I don't really think everything is ok. I just think maybe the ice didn't do what what some of us expected, and am beginning to wonder if it will entirely.


Here in Southern Ontario at 7PM my air conditioner is still spinning, as it has for the past few days. I recall many snowy Halloweens from my long ago childhood, but that's still a week away.
I am more than somewhat relieved that this winter's global ice doesn't seem to be following last year's track. Wipneus's chart scared the bejesus out of me.
Everything will never be "OK" again, but I'm grateful that we didn't slide off on that track.


Terry
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on October 24, 2017, 01:31:22 PM
Can I now exhale?
Terry
JAXA DATA

One should exhale and inhale occasionally to remain extant. However, one should note that while the very unusual events of 2016 have not been repeated, global extent is very low and global area is 2nd lowest.

If the moderate slowdown in arctic extent gain over recent days is matched by a moderate increase in Antarctic extent loss then the graph will go sideways instead of up.  Note that this is not a prediction, merely an observation.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Buddy on October 28, 2017, 05:38:25 PM
Gerontocract:

You are so right....there is not much reason to relax and enjoy "only" being in second place.  And as Tigertown has noted...the additional heat is going somewhere...so it is only a matter of time that combined sea ice worldwide is at record level lows.  Whether it is this year or next year really doesn't matter.  The trend is in place.

Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Tigertown on October 31, 2017, 02:33:36 PM
It looks like we have possibly reached a peak.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Daniel B. on October 31, 2017, 03:11:10 PM
It looks like we have possibly reached a peak.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)

Possibly.  We will see.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on October 31, 2017, 04:03:21 PM
It looks like we have possibly reached a peak.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)

Possibly.  We will see.
JAXA DATA
The table and graph below show the variation in remaining extent gain and date of maximum. As they would say in Melanesia - "wait small".
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on November 05, 2017, 03:47:09 PM
NSIDC DATA - Nearing the end?

https://www.theguardian.com/science/2017/nov/05/donald-trump-accused-blocking-satellite-climate-change-research

It seems that NASA have decided that DMSP satellite F-19 cannot be made operational, and has been abandoned.
DMSP satellite F-20 was destroyed by order of Congress.
The current satellites are already working beyond their shelf-life and the earliest replacement data is 2023.
It is highly likely that NSIDC data will be interrupted temporarily or permanently.

“This is like throwing away the medical records of a sick patient,” said David Gallaher of the National Snow and Ice Data Center in Boulder, Colorado. “Our world is ailing and we have apparently decided to undermine, quite deliberately, the effectiveness of the records on which its recovery might be based. It is criminal.”

However, this criminal act lies not with Trump but at the door of Rep. US Senator Lamar Smith, current chairman of the U.S. House Science, Space and Technology Committee.
He is not standing for re-election next year, and the hurrahs vs eulogies have already started.

http://beta.latimes.com/business/hiltzik/la-fi-hiltzik-lamar-smith-20171103-story.html
https://www.texastribune.org/2017/11/02/lamar-smith-retiring-congress/

JAXA DATA

It now looks likely the Jaxa Extent maximum was on 28th October 2017 at 25,148,160 km2.
The table below shows that with current extent at 25,010,697 km2, no previous year had sufficient extent gain to go over that maximum. (After which 2017 will no doubt behave uniquely).
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on November 06, 2017, 01:02:37 PM
JAXA DATA

5th November: Extent increases by 30 k km2 to 25,042,178 km2, due to
- faster Arctic extent gain,
- slower Antarctic extent loss.
Still 108k km2 less than max on 28th October.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Wipneus on November 08, 2017, 02:36:10 PM
Apologies for mentioning area. NSIDC NT area is definitely making the impression of a nose dive. It dropped 4-sigma below the 1981-2010 mean, which happened before ( during the satellite era) only during one year: 2016.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Shared Humanity on November 08, 2017, 03:32:48 PM
Apologies for mentioning area.

Perhaps you could change the title of this thread and speak to both area and extent in one place.
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: Dharma Rupa on November 08, 2017, 04:43:08 PM
Apologies for mentioning area.

Perhaps you could change the title of this thread and speak to both area and extent in one place.

I agree.  How about: Global Sea Ice According to NSIDC
Title: Re: Global Sea Ice Extent According to NSIDC
Post by: gerontocrat on November 08, 2017, 04:54:53 PM
Apologies for mentioning area.

Perhaps you could change the title of this thread and speak to both area and extent in one place.

I agree.  How about: Global Sea Ice According to NSIDCj
How about global sea ice data ( I post JAXA data), and not buried in the Arctic Sea Ice section?
Title: Re: Global sea ice area and extent data
Post by: Neven on November 08, 2017, 06:37:21 PM
I've changed the thread title.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 08, 2017, 09:18:38 PM
I've changed the thread title.
Merci
Title: Re: Global sea ice area and extent data
Post by: Dharma Rupa on November 09, 2017, 02:07:26 AM
I've changed the thread title.

This is inviting in non-NSIDC data.  I'm guessing you know recent threads well enough that restricting to NSIDC wasn't seen as reasonable.

I would like to see a separate discussion of data providers, but I wouldn't even know how to frame the headline.
Title: Re: Global sea ice area and extent data
Post by: Tigertown on November 09, 2017, 06:55:58 AM
A most excellent idea!
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 10, 2017, 01:41:32 PM
JAXA DATA
9th November Extent  25,039,173 km2, just 109k km2 less than max on 28th October. But Global Area per NSIDC  (merci Wipneus) keeps on going down stongly! Methinks that difference is in the Antarctic.

But 2017 extent is currently nearly 1.6 million km2 GREATER THAN 2016, and it looks to me as if that difference is going to grow.
Title: Re: Global sea ice area and extent data
Post by: Daniel B. on November 10, 2017, 02:15:35 PM
JAXA DATA
9th November Extent  25,039,173 km2, just 109k km2 less than max on 28th October. But Global Area per NSIDC  (merci Wipneus) keeps on going down stongly! Methinks that difference is in the Antarctic.

But 2017 extent is currently nearly 1.6 million km2 GREATER THAN 2016, and it looks to me as if that difference is going to grow.

Me think you are right.
Title: Re: Global sea ice area and extent data
Post by: Tigertown on November 13, 2017, 11:23:07 PM
I jumped the gun earlier this season, but I think maybe now we are in the global extent dive that I feared all along. Maybe.(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 14, 2017, 02:40:13 PM
JAXA DATA

The extent reduction from the Oct 28 maximum to the minimum expected in Feb 18 has barely started - just 5% of the average total extent loss of 9 million km2 done to date  (13th November).Using the previous years' data gives possible minima ranging from 14.75 to 17.25 million km2 c.f. an average (last 10 years) of 16.9 million km2 and the Feb 2017 lowest minimum of 15.6 million km2. The data does point to somewhere between these two values but this is merely an observation, NOT A PREDICTION.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 20, 2017, 03:22:40 PM
JAXA DATA as at 19th Nov 2017

Net extent loss is now well underway. However, 2017 extent is 2.1 million km2 greater than last year, an increase from 1.5 million km2 just 10 days ago.
On the other hand, extent loss on average still has 90% to go.
Title: Re: Global sea ice area and extent data
Post by: Tor Bejnar on November 20, 2017, 03:37:12 PM
If daily ice loss hoovers around the 200K/day (duplicating the last day reported) for the next two weeks, the deficit with 2016 will be erased.  I'm not expecting this to happen (I make no forecast one way or the other), but it shows how insignificant 2 million square kilometers of ice is in the scheme of things.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 23, 2017, 01:48:21 PM
If daily ice loss hoovers around the 200K/day (duplicating the last day reported) for the next two weeks, the deficit with 2016 will be erased.  I'm not expecting this to happen (I make no forecast one way or the other), but it shows how insignificant 2 million square kilometers of ice is in the scheme of things.
JAXA DATA as at 22 Nov. - Extent =  23,467,908 km2

Extent loss per day remains well above average. Difference with 2016 reduced by 360 k km2 in 3 days to +1.76 million km2. The graph suggests that difference is likely to reduce further over the next ten days.
N.B. On average extent loss is only 11% complete as yet.

Title: Re: Global sea ice area and extent data
Post by: Tigertown on November 23, 2017, 04:20:10 PM
Not looking good at all.(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 02, 2017, 03:59:51 PM
Extent is gradually moving towards the pack - slightly slow Antarctic Loss and slightly high Arctic gain. But extent change from max only 12% done.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 03, 2017, 02:00:05 PM
Whoops - table posted yesterday was 23 November. Sorry. Below is corrected table.
Title: Re: Global sea ice area and extent data
Post by: kiwichick16 on December 03, 2017, 08:13:37 PM
@  gerontocrat......moving back towards the pack......agreed.....but still well below average
Title: Re: Global sea ice area and extent data
Post by: RikW on December 04, 2017, 10:07:11 AM
It is funny to see how my mind works with these graphs, when seeing it I think "the global sea ice area is okay/ it's somewhat recovering" while if you only remove 1 year it's crushing all records probably and the forum (and my mind) would be full of blue-ocean-event-next-melt-season posts ;)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 07, 2017, 04:08:45 PM
Mainly JAXA DATA as at 6 Dec

The image below (from NSIDC / Wipneus) shows that extent is still drifting towards the pack. However, extent loss from max to min is only about 25% done..

The table, however, shows the possibility of a very low minimum.

The graph shows that last year the extent loss stalled at the end of December.

One can only wait and see.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 14, 2017, 05:45:45 PM

Another week gone. Herewith mainly JAXA DATA as at 13 Dec

The image below (from NSIDC / Wipneus) shows that extent is still drifting towards the pack. However, extent loss from max to min is only about 33% done..

The table, however, still shows the possibility of a very low minimum.

The graph shows that last year the extent loss stalled at the end of December, after very strong extent loss early

One can only wait and see.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 16, 2017, 11:58:37 AM
JAXA DATA as at 15 Dec

The extent is dropping like a stone - at the moment, though only 37 percent done on average.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 21, 2017, 12:59:17 PM
JAXA DATA as at 20 December 2017
and image from sites.googlegroups.com/site/arctischepinguin/

On average we are 45% down the road from extent max to extent min.
Extent is second lowest in the satellite record.

Last year extent loss slowed sharply from around Xmas day. This shows up well on the image and graph below.

If extent loss from now to minimum is average, it would result in a new record low. (This is an observation, not a prediction.)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 28, 2017, 01:05:08 PM
JAXA DATA as at 27 December 2017
and image from sites.googlegroups.com/site/arctischepinguin/

On average we are 58 % down the road from extent max to extent min.
Extent is second lowest in the satellite record.

Last year extent loss slowed sharply from around Xmas day. This year it hasn't, so far. This shows up well on the image and graph below.

If extent loss from now to minimum is average, it would result in a new record low. (This is an observation, not a prediction.)

The final table shows how global sea ice extent is declining over time.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 31, 2017, 07:41:09 PM
JAXA DATA as at 30 December 2017
and image from sites.googlegroups.com/site/arctischepinguin/

On average we are 63 % down the road from extent max to extent min.
Only about 50 days to go.
The gap with 2016 narrows.
Title: Re: Global sea ice area and extent data
Post by: solartim27 on January 06, 2018, 06:06:45 PM
Some nice charts from the Copernicus program here:
https://climate.copernicus.eu/products/monthly-sea-ice-maps/monthly-maps/december-2017
From their Twitter post
https://mobile.twitter.com/CopernicusECMWF/status/949317113214390272
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 06, 2018, 08:16:55 PM
JAXA still not showing the graphs and the data for 2018, so I had a look at the NSIDC daily data spreadsheet and , of course image from sites.googlegroups.com/site/arctischepinguin/

Note the blip (but is it just a blip) on extent reduction, due to 130 k increase in Arctic sea ice on 5 Jan.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 08, 2018, 03:01:22 PM
NSIDC DATA AS AT 7 JAN

JAXA still not showing the graphs and the data for 2018, so so here again is the NSIDC daily data and, of course, the extent image from sites.googlegroups.com/site/arctischepinguin/

Note the blip was just a blip of extent reduction, now replaced by extent loss in the Arctic and strong extent loss in the Antarctic. Note, for example that on Jan 1 Antarctic Sea Ice extent was 0.85 million greater than 2017, on 7 Jan it is down to 0.53 million.

If this continues a dramatic end to the season in both hemispheres.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 09, 2018, 05:23:37 PM
NSIDC DATA AS AT 8 JAN

JAXA still not showing the graphs and the data for 2018, so so here again is the NSIDC daily data and, of course, the extent image from sites.googlegroups.com/site/arctischepinguin/

Be afraid, be very afraid ?
Title: Re: Global sea ice area and extent data
Post by: Ktb on January 09, 2018, 06:43:55 PM
I think it is worth noting that this is the closest global sea ice has been to the previous year since (record lows) since the divergence of 2017 and 2016 in October.

AND will 2018 be the year that global sea ice extent dips below 16 million sq km??
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 10, 2018, 03:07:20 PM
JAXA DATA AS AT 9 JAN 2018.   At last..

Although extent loss on average is 76% done and on average there are 36 days to go to the minimum on 14th February, over the last 10 years minimum has been reached any time from the 25 th anuary to the 23rd February. Extent is getting closer to the lowest in the satellite record.

Historical data suggests a low or record low minimum, but the table shows the high yearly variation in remaining extent loss and the resulting extent that would cause - anything from 12.8 to 17 million km2.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 10, 2018, 07:59:16 PM
I think it is worth noting that this is the closest global sea ice has been to the previous year since (record lows) since the divergence of 2017 and 2016 in October.

AND will 2018 be the year that global sea ice extent dips below 16 million sq km??
On 9th January with over a month to go, global sea ice extent is below many previous year's minima.

If nothing else, this strongly suggests that the long-term trend is  ↓↓
Title: Re: Global sea ice area and extent data
Post by: Buddy on January 10, 2018, 08:33:42 PM
Quote
On 9th January with over a month to go, global sea ice extent is below many previous year's minima.

First...nice chart!!!  Love the info...

Second....not quite 1.7 mill to go in order to set new record low min.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 12, 2018, 02:36:42 PM
Quote
On 9th January with over a month to go, global sea ice extent is below many previous year's minima.

First...nice chart!!!  Love the info...

Second....not quite 1.7 mill to go in order to set new record low min.

Just for you, Buddy, updated table as at 11 Jan. 1.4 million for new record low. (See how I respond to being stroked).
Title: Re: Global sea ice area and extent data
Post by: Buddy on January 12, 2018, 02:43:04 PM
Quote
Just for you, Buddy, updated table as at 11 Jan. 1.4 million for new record low. (See how I respond to being stroked).

Sweet....:)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 12, 2018, 03:14:50 PM
Latest  graph from sites.googlegroups.com/site/arctischepinguin/.

A little closer every day?
Title: Re: Global sea ice area and extent data
Post by: magnamentis on January 12, 2018, 05:43:17 PM
Latest  graph from sites.googlegroups.com/site/arctischepinguin/.

A little closer every day?

i'm curious whether we shall see such a steep increase in SIE and SIA in the arctic like last year during February?

should that not happen, the global curve as well as arctic Volume would bring us very close to the imminent record summer minimum that will most probably occur during the next sunny (melt friendly) summer season.
Title: Re: Global sea ice area and extent data
Post by: harpy on January 12, 2018, 06:33:08 PM
Would anyone be able to estimate the arctic sea ice extent on that graph which would represent an "ice free arctic"?  Looks like the lowest level was around 16, what number would represent a blue ocean event?

Thanks.
Title: Re: Global sea ice area and extent data
Post by: Tor Bejnar on January 12, 2018, 06:47:33 PM
Harpy,
I think you go to the Arctic Sea Ice Graphs (ASI Graphs (https://sites.google.com/site/arcticseaicegraphs/)) page and look at the several graphs made available there.  Included in the "Daily Graphs" tab are Arctic only graphs, Antarctic only graphs and global graphs, and many others. An ASIG link can be found at the top of every ASI Forum page ("Watch all Graphs on ASI Graphs").  Visitors should also, of course, regularly visit Neven's ASI Blog ("Read All About Arctic on ASI Blog").
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 12, 2018, 07:07:56 PM
Would anyone be able to estimate the arctic sea ice extent on that graph which would represent an "ice free arctic"?  Looks like the lowest level was around 16, what number would represent a blue ocean event?

Thanks.
Often the Arctic and Antarctic extents work in opposite directions. A period of years in which Arctic Sea Extent is reducing quickly sometimes is when the Antarctic is freezing up. At this moment in time(and last year) the Antarctic extent is dropping rapidly while the Arctic is gaining extent slowly - hence the total extent is dropping like a stone. In two months we will be looking at Arctic melt and Antarctic gain.

BUT - to predict, as I know toooo well, is to invite scorn, hollow laughter and other remarks conducive to total humiliation.

BUT - every year CO2 concentrations increase, more solar radiation is  collected by the oceans.

But when a blue ocean event (in the Arctic)? "je ne sais pais".
Title: Re: Global sea ice area and extent data
Post by: oren on January 13, 2018, 12:14:09 AM
Would anyone be able to estimate the arctic sea ice extent on that graph which would represent an "ice free arctic"?  Looks like the lowest level was around 16, what number would represent a blue ocean event?

Thanks.
A blue ocean event in the Arctic would not be on that graph. It would happen in August/September, not in February, so it would be at a different level of global extent. Take typical Aug/Sep Antarctic extent, add 1mil for the usual Arctic "blue ocean" definition, and you'll get your answer.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 13, 2018, 12:19:43 PM
Would anyone be able to estimate the arctic sea ice extent on that graph which would represent an "ice free arctic"?  Looks like the lowest level was around 16, what number would represent a blue ocean event?

Thanks.
A blue ocean event in the Arctic would not be on that graph. It would happen in August/September, not in February, so it would be at a different level of global extent. Take typical Aug/Sep Antarctic extent, add 1mil for the usual Arctic "blue ocean" definition, and you'll get your answer.
For me, looking at global sea ice is really about how much less ocean is covered by ice, with consequences for positive feedback into global warming and other climate changes, and something to stick up the nose of climate change denier trolls.

so here is JAXA DATA as at 12th February. About 33 Days to go =/- 10 days?

Title: Re: Global sea ice area and extent data
Post by: RikW on January 13, 2018, 12:32:59 PM
A finish not in the top 3 would be a miracle, even 3rd place would surprise me
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 14, 2018, 04:14:52 PM
JAXA having a day off - so here is NSIDC daily data (Arctic, Antarctic, Global) plus extent and area graphs from arctischepinguin.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 19, 2018, 10:44:38 AM
JAXA DATA AS AT 18 JAN 2018

On average, extent loss to minimum is about 88% done. 2017 extent at this date was 0.56 million km2 less than 2018, but extent loss in 2017 from this date was a very low 0.37 million km2 compared with the average of 1.1 million km2.

A record low is thus still very possible, but extent gain in the Arctic and extent loss in the Antarctic is entering the period of transition.
Title: Re: Global sea ice area and extent data
Post by: RikW on January 19, 2018, 11:19:30 AM
I still guess it will be a 2nd or 3rd place finish. There isn't many ice to melt left in the antarctic
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 20, 2018, 05:01:42 PM
JAXA on holiday today. Herewith are artischepinguin images from NASA for 19 Jan for area and extent.

Arctic ice gain stalled, Antarctic ice loss slowed. Global extent looks about 2nd lowest with some more loss to go?



Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 21, 2018, 01:14:48 PM
JAXA DATA AS AT 20 JAN

On average extent reduction from maximum is 90 % done, just 1 million km2 to go, which would produce a new record low minimum. Extent has now narrowed to just 0.25 million greater than 2017, the year of record low that was so astonishing at the time.  Only 4 years have ended up with a lower low than the 20 Jan 2018 extent.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 22, 2018, 11:31:38 AM
JAXA DATA 21 JAN

Another day, another 140 k km2 extent drop. Extent on 21 jan now lower than the minimum for all years except two, 2006 (98k km2) and 2017 (555k km2).

First or second lowest minimum now almost certain.
Title: Re: Global sea ice area and extent data
Post by: Ktb on January 22, 2018, 06:29:05 PM
According to NSIDC any decrease in extent today will push 2018 below 2017, into first place
Title: Re: Global sea ice area and extent data
Post by: Buddy on January 22, 2018, 07:05:57 PM
Quote
First or second lowest minimum now almost certain.

Fascinating to watch as always....especially now that the Antarctic is heading "south" with a good head of steam over the last couple of years.

Will also be interesting to see how much this impacts the POLITICAL "climate"  ;) in the US and elsewhere.  Let's face it....its not IF most people are going to change their mind on global warming....it is WHEN.  There are the early adopters.....and there are the late adopters.

Mathematical and physical FACTS don't go away.  And SLOWLY people are being peeled away from the dark side.  Impacts like new record lows in sea ice continue to beat on the other side.....and they have a LOSING proposition that they are clinging to.   
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 22, 2018, 07:21:25 PM
It is getting late for old fogies like me on this side of the Atlantic, so here are two images extracted from https://sites.google.com/site/arctischepinguin/home/global-sea-ice, NSIDC global area and global extent.

I do not remember another time when for two years in a row the data and graphs left the pack behind in the dust.

Title: Re: Global sea ice area and extent data
Post by: Tigertown on January 22, 2018, 09:32:29 PM
We knew this was coming. Its just a matter of how low it will get to now. Will the global extent drop below 16M km2? It may even approach 15M km2. How big of a sputter like this can a global system survive?
Title: Re: Global sea ice area and extent data
Post by: Buddy on January 22, 2018, 09:53:32 PM
Quote
We knew this was coming. Its just a matter of how low it will get to now. Will the global extent drop below 16M km2? It may even approach 15M km2. How big of a sputter like this can a global system survive?

You are so right.  More dark ocean...... = more heat. 



Title: Re: Global sea ice area and extent data
Post by: magnamentis on January 22, 2018, 10:27:29 PM
Quote
First or second lowest minimum now almost certain.

Fascinating to watch as always....especially now that the Antarctic is heading "south" with a good head of steam over the last couple of years.

Will also be interesting to see how much this impacts the POLITICAL "climate"  ;) in the US and elsewhere.  Let's face it....its not IF most people are going to change their mind on global warming....it is WHEN.  There are the early adopters.....and there are the late adopters.

Mathematical and physical FACTS don't go away.  And SLOWLY people are being peeled away from the dark side.  Impacts like new record lows in sea ice continue to beat on the other side.....and they have a LOSING proposition that they are clinging to.   

yeah, i thought along the same lines, trump with his childish tweets about where the climate change is must have seriously pissed of saint peter, at least one could get the impression when looking at the latest development and temp anomalies. (partly kidding the St. P. Part LOL i'm not sure about other countries but here in europe st. peter is the guy responsible for the weather ;) )
Title: Re: Global sea ice area and extent data
Post by: Paddy on January 22, 2018, 11:06:12 PM
We knew this was coming. Its just a matter of how low it will get to now. Will the global extent drop below 16M km2? It may even approach 15M km2. How big of a sputter like this can a global system survive?

My guess is that it'll be a similar minimum to last year, but naturally, nobody knows.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 24, 2018, 01:47:48 PM
JAXA DATA Global Extent as at 23 Jan

With, on average, just 3 weeks and 9 % (0.8 million) of extent loss to go, Jan 23 extent today is now lower than all previous years' minima except 2017. Jan 23 2017 extent was just 2.370 km2 less than 2018.

If, always a very big if, extent reduction is average, the 2017 extent minimum would be nearly 400,000 km2 less than the 2017 record low minimum.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 24, 2018, 02:56:32 PM
BUT -

NSIDC showing the opposite over the last couple of days - i.e. increasing global extent.

Once more into the waiting game

https://sites.google.com/site/arctischepinguin/home/global-sea-ice
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 25, 2018, 04:57:31 PM
NSIDC data says that due to increases in Arctic extent, global extent going up - while JAXA says extent has stalled (but down a tiny bit).

https://sites.google.com/site/arctischepinguin/home/global-sea-ice
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 25, 2018, 08:41:31 PM
I thought I would step back and have a look at global annual averages over the last few years using JAXA data as relief from the microscope of daily changes.

I think the graph below is OK. Note the dips around 2007 and 2012 (Arctic Sea Ice major losses) and the 2015 high - Antarctic record highs. The overall trend is, obviously - down.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 27, 2018, 12:54:42 PM
JAXA DATA - Global Extent as at 26 Jan

Extent reduction a bit lower than average over the last two days.

With, on average, less than 3 weeks and 7 % (0.64 million km2) of extent loss to go, Jan 23 extent today is now lower than all previous years' minima except 2017, which was at minimum 280k lower.

If, always a very big if, extent reduction is average, the 2017 extent minimum would be about 360k km2 less than the 2017 record low minimum.
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on January 29, 2018, 01:25:13 PM
I thought I would step back and have a look at global annual averages over the last few years using JAXA data as relief from the microscope of daily changes.

I think the graph below is OK. Note the dips around 2007 and 2012 (Arctic Sea Ice major losses) and the 2015 high - Antarctic record highs. The overall trend is, obviously - down.

About time the Antarctic fresh runoff meets normal temperatures. The deniers have had too much visibility and spewed too much crap with this one.
Title: Re: Global sea ice area and extent data
Post by: Sterks on January 29, 2018, 10:50:42 PM
I thought I would step back and have a look at global annual averages over the last few years using JAXA data as relief from the microscope of daily changes.

I think the graph below is OK. Note the dips around 2007 and 2012 (Arctic Sea Ice major losses) and the 2015 high - Antarctic record highs. The overall trend is, obviously - down.
Not so obviously, when you cut the plot about somewhere 2015 and was, "obviously", up.
Unsettled I'd say, which is the same as no freaking idea.
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on January 30, 2018, 03:36:24 AM
I thought I would step back and have a look at global annual averages over the last few years using JAXA data as relief from the microscope of daily changes.

I think the graph below is OK. Note the dips around 2007 and 2012 (Arctic Sea Ice major losses) and the 2015 high - Antarctic record highs. The overall trend is, obviously - down.
Not so obviously, when you cut the plot about somewhere 2015 and was, "obviously", up.
Unsettled I'd say, which is the same as no freaking idea.

Yeah, I remember cussing at that graph (and thus to reality) in 2014, but it prevented me from taking a rampage at deniers on select sites. I'm glad that the casual observer of sciency stuff no longer can throw this at the less casual observer. Not good of course, but some engineering types won't response to a graph of greenland melt until this had been explained to their satisfaction. You try to explain fluid mechanics to a classical mechanical engineer.

If you try that, one possible way might be comparing the sea ice destruction to a shell of a car which is almost rusted through. Ok, the mechanism in this case is chemical degradation as opposed to thermal rotting of the ice but the end result is the same, one day the car still resembles a shell of a car, and after the next storm you have a pile of rust, similarly a rain storm over ice might destroy the whole area of ice it rains onto.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 30, 2018, 01:50:51 PM
JAXA GLOBAL EXTENT DATA AS 29 JAN

Extent is  15,784,434 km2, just 197k km2 above the 2017 recird low

On average about 17  days, just 0.47 million km2 and 5% of extent loss to go. Extent minimum date in the past has ranged from 8 days to to 25 days from Jan 29. Note that days to go do not seem to correspond to min and max extent loss from now. So who knows the final result, though a record low is still on the cards.

In the last three days daily extent loss has nearly stalled - slower Antarctic extent loss, higher Arctic extent gain.
Title: Re: Global sea ice area and extent data
Post by: magnamentis on January 30, 2018, 08:09:58 PM
I thought I would step back and have a look at global annual averages over the last few years using JAXA data as relief from the microscope of daily changes.

I think the graph below is OK. Note the dips around 2007 and 2012 (Arctic Sea Ice major losses) and the 2015 high - Antarctic record highs. The overall trend is, obviously - down.
Not so obviously, when you cut the plot about somewhere 2015 and was, "obviously", up.
Unsettled I'd say, which is the same as no freaking idea.

please put into account the time spans we should have in mind here;

what we are observing now withing let's say (arbitrary) 100 years has taken place before over
thousands and at times millions of years so just cutting out a few years that suit a point is not a valid approach to deny the trend which is DOWN of course and obvious as well.

it's really like politics, even though most people are aware what happens and what's to do, the moment one guy comes to the point someone with a basically similar point of view would try to deny that. must be some kind of reflex, based on........ (not saying it)

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 03, 2018, 12:24:43 PM
JAXA DATA - Extent as 2 Feb is  15,917,505 km2
Extent gain in the last three days due to Arctic sea ice gain continuing to accelerate.  Average loss of 0.35 million in  these last two weeks (or as little as 4 days or as many as 21 days) would produce a near equal result to 2017 (a record low) .
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 05, 2018, 12:05:27 PM
JAXA GLOBAL SEA ICE EXTENT as at at 4 February 15,846,535 still about 56 k above the minimum so far this year on the 30th January, and 137k above the

However, in the last two days extent has begun to drop, due to less gain in the Arctic, where the current drama unfolding will be impacting extent (though it could temporarily increase extent as ice is spread out).

If extent loss in the average last 10 days, 3%, 0.3 million km2 occurs, the minimum would be just 40,000 km2 less than the 2017 record low. 2nd lowest has already happened.
Title: Re: Global sea ice area and extent data
Post by: Ktb on February 07, 2018, 02:34:05 PM
On mobile right now so I won't bother linking images but according to NSIDC and Wipneus: significant drops in both area and extent yesterday, appears to have been lead by decent drops in the arctic. Both now below 2017.
Title: Re: Global sea ice area and extent data
Post by: RikW on February 07, 2018, 04:49:14 PM
yeah, Area and extent lowest since start of measurements:

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_area_byyear_b.png

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_extent_byyear_b.png

For area it's the first time since august/september last year
Title: Re: Global sea ice area and extent data
Post by: Thomas Barlow on February 07, 2018, 06:13:55 PM
If I was to cite ArctischePinguin elswhere (because global sea-ice is at record low again today), how should I cite him? I don't know his background, so far I just said "a blogger known for his skill with this, and verified by other data experts"
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on February 07, 2018, 07:54:53 PM
"Wipneus@asiforum graphing&calcuöating from direct satellite data"?
There's very little preventing people w/ skill doing the exactly same.
Title: Re: Global sea ice area and extent data
Post by: Thomas Barlow on February 07, 2018, 09:46:43 PM
"Wipneus@asiforum graphing&calcuöating from direct satellite data"?
There's very little preventing people w/ skill doing the exactly same.
Thanks !
Title: Re: Global sea ice area and extent data
Post by: harpy on February 07, 2018, 10:17:11 PM
Why is it that the lowest extent is during January and the highest during the summer months on the above graph?
Title: Re: Global sea ice area and extent data
Post by: josh-j on February 07, 2018, 10:42:16 PM
Why is it that the lowest extent is during January and the highest during the summer months on the above graph?

That graph is for global sea ice, so includes both Arctic and Antarctic sea ice. So the low period is during the antarctic summer.  :)
Title: Re: Global sea ice area and extent data
Post by: oren on February 08, 2018, 01:58:10 AM
Why is it that the lowest extent is during January and the highest during the summer months on the above graph?

That graph is for global sea ice, so includes both Arctic and Antarctic sea ice. So the low period is during the antarctic summer.  :)
And the Antarctic, for several reasons, has much higher seasonal variability than the Arctic, therefore the global graph's min and max follow the Antarctic graph.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 08, 2018, 11:10:00 AM
JAXA Arctic + Antarctic Extent as at 7 Feb 2018 15,619,229 km2

The last two days have seen a 97k ( Feb) and 102 k (7Feb) km2 extent loss, due to extent losses in both the Arctic (the cyclone) and the Antarctic (" a bit of a puzzle"  NSIDC Jan 18 Arctic Sea Ice News.

With just 7 days, 0.23 million km2, 2.5% of average extent loss to go, a new record low is now very much on. However, previous years say that the season could be finished already or up to 16 days to go. Nevertheless another paltry 31k km2 extent loss would equal 2017's record low, and on 7 Feb was 87k km2 below the 2017 extent on that date.
Title: Re: Global sea ice area and extent data
Post by: Lord M Vader on February 08, 2018, 01:46:08 PM
The daily global sea ice extent for February 7 is now 16,055 Mn km2 according to NSDIC numbers. Is this the lowest global sea ice extent ever or is 2017 still in charge?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 08, 2018, 02:42:02 PM
The daily global sea ice extent for February 7 is now 16,055 Mn km2 according to NSDIC numbers. Is this the lowest global sea ice extent ever or is 2017 still in charge?
NSIDC says 2018 is 134k < 2017, and 80K < the 2017 minimum
JAXA says 2018 is 87k < 2017, and 32 K > the 2017 minimum (with 7 days to go).

But that, methinks, is not in charge due to extreme volatility at this time of transition.
Title: Re: Global sea ice area and extent data
Post by: Ktb on February 08, 2018, 03:33:05 PM
Record low NSIDC, who's got the champagne? Gotta celebrate even though it is similar to those depressing movies where a kid throws a birthday party and nobody shows up.
So...yay? :-\
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 08, 2018, 03:51:39 PM
Record low NSIDC, who's got the champagne? Gotta celebrate even though it is similar to those depressing movies where a kid throws a birthday party and nobody shows up everybody throws up
So...yay? :-\
Ok, so after last year's total humiliation over the JAXA poll for Arctic maximum, I suppose there is some sort of satisfaction in being in the right ball park on something.
Title: Re: Global sea ice area and extent data
Post by: Thomas Barlow on February 08, 2018, 06:02:53 PM
The daily global sea ice extent for February 7 is now 16,055 Mn km2 according to NSDIC numbers. Is this the lowest global sea ice extent ever or is 2017 still in charge?
Looks like it is the lowest global sea-ice extent on record.
(thanks for graph, Wipneus)
https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_extent_byyear_b.png?attachauth=ANoY7crdcunJV8CYQX88KM7F2XEyb-Sl00hFVW9aFdA1CbyMImk3CCcm1oksnGAW7bX2asq04Ed1JXwRLIWANxFPmq2oDzT3PKmO_pr-JEAWxu5LwdMv9mugH-Mse6KsknROvHqo-DfohUTkM_BIAB6mrMtaaR0DjG32DH8aJsf7KYXZNgUJuvgnD761ewmQZD92PJlAml7pHKjQ4gKxy1SN5oMGNKgZ5tF7X4Q47oW06P4wvqG0eToy5AyApNT_E5PzgB6Eby2wAmTFvxqQSEu4tPcyxast4c9X-_Ah-RS9kKYsBEvqBeY%3D&attredirects=0
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 09, 2018, 10:44:11 AM
JAXA Arctic + Antarctic Extent as at 8 Feb 2018  15,596,102 km2

A modest 26 k km2 extent loss, due to small extent losses in both the Arctic and the Antarctic

With just 6 days, 0.20 million km2, 2.2% of average extent loss to go, there is just 8k km2 loss to go for a new record low.  NSIDC data says it already is a new record.
Title: Re: Global sea ice area and extent data
Post by: BenB on February 09, 2018, 11:00:31 AM
Given the huge year-to-year variability, it's pretty striking that the two most recent years are in a statistical dead heat for the lowest on record (and have been dominating the daily record lows for extended periods). You might even be tempted to think that something is happening to our climate and to the cryosphere...
Title: Re: Global sea ice area and extent data
Post by: charles_oil on February 09, 2018, 11:23:34 AM

Luckily the EPA may think that's great ..... wonder who will take credit ?


https://edition.cnn.com/2018/02/08/politics/scott-pruitt-climate-change/index.html


Sorry - should probably be in Trump assaults section !
Title: Re: Global sea ice area and extent data
Post by: PSJ on February 09, 2018, 11:29:07 AM
Marking the new NSIDC global extent low, this graph is what really knocks me off my feet. Are we in new quasi-equilibrium of -3 standard deviations? How long will we be here for?


Source
https://sites.google.com/site/arctischepinguin/home/global-sea-ice

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 09, 2018, 12:16:32 PM
Marking the new NSIDC global extent low, this graph is what really knocks me off my feet. Are we in new quasi-equilibrium of -3 standard deviations? How long will we be here for?
The table below (JAXA DATA) shows how 2016 and 2017 are completely outliers compared with the previous years. One outlier may be just a one-off - but two. But I guess 3 years is needed to start making a series.
Title: Re: Global sea ice area and extent data
Post by: Buddy on February 09, 2018, 01:45:31 PM

Quote
Quote
Marking the new NSIDC global extent low, this graph is what really knocks me off my feet. Are we in new quasi-equilibrium of -3 standard deviations? How long will we be here for?


The table below (JAXA DATA) shows how 2016 and 2017 are completely outliers compared with the previous years. One outlier may be just a one-off - but two. But I guess 3 years is needed to start making a series.

I'm afraid "old MO" (momentum) is awfully difficult to stop or even slow down now that we are this far along.  Next 10 years surely will be more "gobsmacking" than the last 10.

Although....I see that Scottie Pruitt thinks that global warming may be a good thing.  He spent 15 years lying about global warming happening.....but now that he can't spin that lie any longer...he is off to his next lie.  Too bad Scottie isn't very good at math and physics.  Wonder what the folks in Boston, NY City, Miami, Shanghai, Seattle, and billions of people on coasts around the world are going to think of Scottie's new take on things?   ;)


Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 09, 2018, 03:04:54 PM
NSIDC daily global extent UP 62K, Arctic +3k, Antarctic 59K.

But, tomorrow is another day.
Title: Re: Global sea ice area and extent data
Post by: Thomas Barlow on February 10, 2018, 12:43:11 AM
NSIDC daily global extent UP 62K, Arctic +3k, Antarctic 59K.

But, tomorrow is another day.
Looks like both Arctic and Antarctic are both at lowest extent for Feb. 8th
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: Global sea ice area and extent data
Post by: DavidR on February 10, 2018, 02:59:08 AM
NSIDC daily global extent UP 62K, Arctic +3k, Antarctic 59K.

But, tomorrow is another day.

A slight correction to the above figures is needed!
Arctic +59K, Antarctic +3k.
The Antarctic is currently 244K above the record low

The Antarctic is just  55K above the 2nd lowest in the record 1997 @ 2.264.

The smallest decline to minimum from this date is 175K and the average  is 374K.

Three quarters of the declines from this date will lead to a new record low minimum while 60% would lead to a below 2 M figure.  In the Arctic three quarters of the increases from today to the max would also lead to a record low maximum.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 10, 2018, 11:41:19 AM
Thanks DavidR for the correction (Nurse! Where are you?).

As JAXA is on holiday today, I though why not another look back at history. The graphs below are from the NSIDC spreadsheet. They are looking back, each measurement being the average of the previous 365 daily extents.

If nothing else, the graph does show that there is only one direction for Arctic Sea Ice - down. Of note also is the way Antarctic Sea ice rose and fell over the last 6 years to an extent not seen before.

The last point is that despite record low or nearly record low extents currently in both Arctic and Antarctic extents, the average is going up at the moment.

Sea ice going down - yes, ice apocalypse - not yet.
Title: Re: Global sea ice area and extent data
Post by: Alexander555 on February 10, 2018, 01:25:14 PM
Thanks DavidR for the correction (Nurse! Where are you?).

As JAXA is on holiday today, I though why not another look back at history. The graphs below are from the NSIDC spreadsheet. They are looking back, each measurement being the average of the previous 365 daily extents.

If nothing else, the graph does show that there is only one direction for Arctic Sea Ice - down. Of note also is the way Antarctic Sea ice rose and fell over the last 6 years to an extent not seen before.

The last point is that despite record low or nearly record low extents currently in both Arctic and Antarctic extents, the average is going up at the moment.

Sea ice going down - yes, ice apocalypse - not yet.


What is your opinion about the solar cycle. If i understand it well , than we are now at the coldest point. If it has an impact at all. But they are talking about the little ice age in Europe at a moment there were no sun spots. If you look at the result of ice volumes from the last six years, and we are going into a periode with warmer conditions. If my interpretation is good. Than it sounds like we are going to lose some more ice in the future.

https://eos.org/research-spotlights/model-of-solar-cycles-impact-on-climate-gets-upgrade
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 10, 2018, 01:51:32 PM
Not a clue, Alexander 555.

Looking at the (I have to say, classy) image, the 2007 big Arctic ice melt happened nearly at the bottom of the sunspot cycle, while in 2012 it was near the top. So no correlation there.

And then you have nothing from the article to tell us on likely variable effects in high latitudes, mid-latitudes and the tropics. Without a scientist to tell me, I have not and will not have a clue.

Meanwhile, things like aerosols (will India and China reduce coal and their industries) and permafrost, (will the Eastern Siberian Arctic Shelf start burping methane big-time in the near future) are but two more of many variables that could overwhelm the gradual downwards trend in sea ice.

People like me can only watch, wonder, and inform and educate the wider world when possible (for me, since about 1990).
Title: Re: Global sea ice area and extent data
Post by: Sleepy on February 10, 2018, 02:22:48 PM
If my interpretation is good. Than it sounds like we are going to lose some more ice in the future.
We will loose more ice, but not because of the sun.
http://spot.colorado.edu/~koppg/TSI/#TSI_data_record (http://spot.colorado.edu/~koppg/TSI/#TSI_data_record)
http://solar-center.stanford.edu/sun-on-earth/glob-warm.html (http://solar-center.stanford.edu/sun-on-earth/glob-warm.html)

A couple of years back there were discussions about a new little ice age spurred by deniers. But we have effctively disarmed ice ages for many thousands of years to come. Unless something truly drastic happens.
Title: Re: Global sea ice area and extent data
Post by: Alexander555 on February 10, 2018, 02:34:28 PM
And do you know if there is a correlation between these sunspots and the temperature on earth ? I'm not a denier. Even without all the carbon pollution i think the earth will warm. By cutting all these forest on the equator we transform them into an oven. So if you take everything together, fossil fuel warming, the ovens on the equator, and maybe some extra from the sun. But i haven't read much about that sun cycle. That's why i ask, i was just wondering.
Title: Re: Global sea ice area and extent data
Post by: Alexander555 on February 10, 2018, 02:40:50 PM
I have seen the link now, they are talking about a small difference. That means it can add a little.
Title: Re: Global sea ice area and extent data
Post by: Gray-Wolf on February 10, 2018, 02:43:43 PM
We do have a link between northern blocking and low solar ( our winter of 09/10 in the UK arrests to that! ) so does this 'blocking' run into spring?
We are just having a major SSW and , in the UK at least, folk are wondering if this will lead to northern blocking and so put the UK under easterlies and cold out of Siberia? Us running down into low solar might help with the process?
This High pressure would produce a good start to the melt season allowing a sunny start to the season?
07' was in the period of losing sun spot numbers and 2010's volume loss was at minimum. 2012 was as the sun spot numbers were slowly increasing so still within the 'solar min'
So I wonder if the high pressure's associated with low solar bring a good melt momentum to a melt season and so allow low number finishes even if July/Aug are cloudy/cool/stormy?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 10, 2018, 02:47:54 PM
Meanwhile, back to the present.

NSIDC DATA as at Feb 9th

Extent down 106k to 16.011 million km2, 124k below the 2017 record low.

Arctic exactly reversed the previous day gain of 57k,
Antarctic dropped by 49k, at 2.270 million km2, now 195k to go to match the 2017 record low.
Title: Re: Global sea ice area and extent data
Post by: Sleepy on February 10, 2018, 04:09:47 PM
I have seen the link now, they are talking about a small difference. That means it can add a little.
First, I never called you a denier, just tried to keep it short because this is OT here.

From the second link I posted and the top link:
Solar Influences on Climate
http://solar-center.stanford.edu/sun-on-earth/Solar%20Influences%20on%20Climate-2009RG000282.pdf (http://solar-center.stanford.edu/sun-on-earth/Solar%20Influences%20on%20Climate-2009RG000282.pdf)
Section 6.4 Climate Change
Quote
A value of 0.24 W m−2 solar radiative forcing difference from Maunder Minimum to the present is currently considered to be more appropriate.

Remember, the current cycle (24) is not as low as during the Maunder minimum, not even Dalton, it's similar to those around 1900. As of December 2017 the strength and trend of the southern polar field hints at a cycle 25 with a magnitude slightly stronger than that of cycle 24.
Title: Re: Global sea ice area and extent data
Post by: FishOutofWater on February 10, 2018, 04:34:42 PM
The effect of a prolonged solar minimum would be modest - tenths of a degree C. It could affect weather patterns, however, as ocean heat would be redistributed in response to the slightly shifted regional radiation balance.

There was a regional "little ice age" that primarily affected Europe. It was mainly caused by northern hemisphere volcanoes. The Maunder minimum in sunspots had an modest impact. Southern hemisphere temperatures dropped slightly.

A deep and long solar minimum would cause a modest drop in forcing that would be significantly less than the increase in forcing caused by increasing levels of GHGs.

I'm writing this from memory based on reading many research papers and discussions.
Title: Re: Global sea ice area and extent data
Post by: DavidR on February 10, 2018, 04:43:31 PM
And do you know if there is a correlation between these sunspots and the temperature on earth ? I'm not a denier. Even without all the carbon pollution i think the earth will warm. By cutting all these forest on the equator we transform them into an oven. So if you take everything together, fossil fuel warming, the ovens on the equator, and maybe some extra from the sun. But i haven't read much about that sun cycle. That's why i ask, i was just wondering.
The correlation between the solar cycle and temperatures on earth is well established.  At the top of a solar cycle temperatures on earth are roughly  0.3 degrees hotter than at the bottom, The same range holds for ENSO.  However both of these are overlaid on a rising background temperature of 0.15 degrees per decade  The consequence is that  we see periods of rapid increase followed by  longer periods of slow decline that do not return temperatures to their previous levels.

With the current cycle being quite small the impact on temperature are lessened and rise will be more consistent. If we get a maunder minimum as predicted by some, there will be no period of temporary cooling and temperatures will rise with fewer fluctuations over the next  few decades.
Title: Re: Global sea ice area and extent data
Post by: Alexander555 on February 10, 2018, 05:14:14 PM
I have seen the link now, they are talking about a small difference. That means it can add a little.
First, I never called you a denier, just tried to keep it short because this is OT here.

From the second link I posted and the top link:
Solar Influences on Climate
http://solar-center.stanford.edu/sun-on-earth/Solar%20Influences%20on%20Climate-2009RG000282.pdf (http://solar-center.stanford.edu/sun-on-earth/Solar%20Influences%20on%20Climate-2009RG000282.pdf)
Section 6.4 Climate Change
Quote
A value of 0.24 W m−2 solar radiative forcing difference from Maunder Minimum to the present is currently considered to be more appropriate.

Remember, the current cycle (24) is not as low as during the Maunder minimum, not even Dalton, it's similar to those around 1900. As of December 2017 the strength and trend of the southern polar field hints at a cycle 25 with a magnitude slightly stronger than that of cycle 24.


Thanks for the link, i'm going to read it this evening. For the moment i'm only at page six, and i have a few things to do. But it looks interesting. But when i look at the pics i can imagine there is a little correlation. And probably it would be more clear if we could filter the other effects out. If you look at the points where there are few sun spots, just after 87 there is a little uptick in extent. In 97 it looks like there was only a moment with zero spots, and extent stayed flat for almost 4 years. In 2008-2010 it was a much longer periode with only very few spots. And in the years after extent went up like 1,5 million square kilometers. And what do you mean with a magnitude slightly stronger ? More sun spots, or a longer time without spots ?
Title: Re: Global sea ice area and extent data
Post by: Neven on February 10, 2018, 07:05:39 PM
On-topic, please. Take it elsewhere, or open a separate thread.
Title: Re: Global sea ice area and extent data
Post by: Thomas Barlow on February 10, 2018, 08:16:11 PM
Meanwhile, back to the present.

NSIDC DATA as at Feb 9th

Extent down 106k to 16.011 million km2, 124k below the 2017 record low.

Arctic exactly reversed the previous day gain of 57k,
Antarctic dropped by 49k, at 2.270 million km2, now 195k to go to match the 2017 record low.
Did global sea ice reach the lowest extent ever recorded on the day Elon Musk put more than 500,000 kgs of CO2 into the atmosphere to launch a 2,000kg payload into space?
The irony is mind-blowing.
Title: Re: Global sea ice area and extent data
Post by: harpy on February 10, 2018, 08:23:21 PM
Meanwhile, back to the present.

NSIDC DATA as at Feb 9th

Extent down 106k to 16.011 million km2, 124k below the 2017 record low.

Arctic exactly reversed the previous day gain of 57k,
Antarctic dropped by 49k, at 2.270 million km2, now 195k to go to match the 2017 record low.

Wow, that's incredible. 

What is the current global average temperature above the pre-industrial baseline right now (Mid February 2018)??
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 11, 2018, 03:34:21 PM
Meanwhile, back to the present.

NSIDC DATA as at Feb 9th

Extent down 106k to 16.011 million km2, 124k below the 2017 record low.

Arctic exactly reversed the previous day gain of 57k,
Antarctic dropped by 49k, at 2.270 million km2, now 195k to go to match the 2017 record low.

Wow, that's incredible. 

What is the current global average temperature above the pre-industrial baseline right now (Mid February 2018)??
daily data not available. A shade over 1 degree celsius, about 1.8 degrees fahrenheit, but currently increasing at about 0.13 degrees per decade (i.e. faster). The Arctic is warming faster - no data but Alaska just had its warmest December on record, with a statewide average temperature anomaly of 15.7 degrees Fahrenheit above average for the month.

Meanwhile, NSIDC revised its daily extents for the Antarctic down a bit. Global extent now at 16.066 million km2, still going down and still a record low.

With luck JAXA will return tomorrow.
Title: Re: Global sea ice area and extent data
Post by: harpy on February 11, 2018, 04:25:46 PM
Where do you find that information on global average temperature exactly?

I've seen 1.5C above baseline, 1C is a bit low.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 11, 2018, 04:31:27 PM
Where do you find that information on global average temperature exactly?

I've seen 1.5C above baseline, 1C is a bit low.

Google.
Title: Re: Global sea ice area and extent data
Post by: harpy on February 11, 2018, 04:34:19 PM
Where do you find that information on global average temperature exactly?

I've seen 1.5C above baseline, 1C is a bit low.

Google.

Google is not a reliable source.  No wonder you think we're only at 1C above baseline.
Title: Re: Global sea ice area and extent data
Post by: harpy on February 11, 2018, 04:36:56 PM
For example look at this graph from NASA of all places:

https://climate.nasa.gov/vital-signs/global-temperature/

This is 100% crap because they're skewing the entire graph and reporting a false final figure based on a baseline that is not accurate.  The temperature data is fine, but it's shifted down nearly .5C to represent a screwed up baseline (What the F NASA?).    Baseline is 1750-1850, not 1950-1980+ anything.  This is 100% political - only a mentally challenged scientist would use a false baseline like this and present the data to the public.

They're obviously not mentally challenged at NASA, so this is almost certainly political.

If you look on the graph you can clearly see that it's skewed down, and temperatures are currently hovering around 1.5C, not 1C.
Title: Re: Global sea ice area and extent data
Post by: Tetra on February 11, 2018, 04:44:07 PM
For example look at this absolute garbage graph:

https://climate.nasa.gov/vital-signs/global-temperature/

This is 100% crap.  First of all, they're using a screwed up baseline.  Baseline is 1750-1850, not 1900+ anything.

If you look on the graph you can clearly see that it's skewed down, and temperatures are currently hovering around 1.5C, not 1C.

There's a reason why measuring is kept at 1900+. The little ice age. https://en.m.wikipedia.org/wiki/Little_Ice_Age

Temps were already naturally down, so measuring from them would be anomalous.

1900+ is when large industrial kicks in anyway. And all the IPCC reports and such, when they say 1C use this time period.

And we don't have reliable data for pre 1900. 1951 was when proper documentation by NASA started.

The 1951-1980 is a good thirty year scientific baseline because a) the 1980s were way warmer on a 0.2c+ Per decade trend, and b) it gives us a good average to measure from.

You're comparing apples and oranges. Your 1.5C is a very, non scientific anomalous claim. Please back it up with an actual source by a documented scientist arguing against the NASA claim.

They are literally going with their own data.

If we were at that measurement, current warming would be 1/2x worse.
Title: Re: Global sea ice area and extent data
Post by: binntho on February 11, 2018, 05:32:31 PM
Where do you find that information on global average temperature exactly?

I've seen 1.5C above baseline, 1C is a bit low.

Google.

Google is not a reliable source.  No wonder you think we're only at 1C above baseline.
I'm not sure why you think there should be a particular "baseline" - but palaeotemperatures are typically shown against baseline 1950-1980 or "1970". HadCRUT which has the longest contiguous temperature record, since 1850, uses 1960-1990 as baseline. But if recalculated against a 1850-1880 baseline shows approximately 1 degree warming.

Global temperature estimates for the holocene show the lowest temperatures appr. 300-500 years ago, see https://en.wikipedia.org/wiki/Little_Ice_Age#/media/File:2000_Year_Temperature_Comparison.png , but mid 19th century was pretty cool as well. the period 1850-1880 apparently slightly colder than 1750-1850 from eyeballing the graph.

All in all a 1 degree warming over the last 150 years or so, although I have seen on occasion the number 1,5 mentioned.

This graph from Wikipedia is probably based on NASA GISS (although it doesn't say), if you were to pick 1900-1930 as a baseline (slightly colder than 1850-1880) you might get around 1,2 degrees warming.https://en.wikipedia.org/wiki/Global_warming#/media/File:Global_Temperature_Anomaly.svg
Title: Re: Global sea ice area and extent data
Post by: harpy on February 11, 2018, 05:37:08 PM
There's no way that 1950-1980 is a baseline, that's pure garbage.  Anyone who thinks that an acceptable baseline is anything beyond 1850 is wrong.

PRE INDUSTRIAL is the correct baseline, that's 1750-1850 or earlier, nothing after that point.  Using data before that point is acceptable, preferably average data from the past 5000 approximately (post glacial period) years PRIOR to 1750.  Any point since CO2 emissions began to rise due to human causes is not a baseline, and is false data and garbage.

IDK if you are having a difficult time understanding or not, but those data below 0 are wrong - the entire graph is being skewed upwards.  The 1880-1990 data should be around or slightly above 0, not below zero.

IDK why people have such a hard time understanding what an accurate baseline is.

Current global average temperature above pre industrial baseline is 1.5C above baseline in 2018.  We hit nearly 2C above baseline in 2015-2016.
Title: Re: Global sea ice area and extent data
Post by: FishOutofWater on February 11, 2018, 06:40:29 PM
For everyday climatology 30 year baselines are used. Therefore the relatively warm period 1980 to 2010 is used. In fact, you see all different baselines on the net. You need to be very careful to compare equivalent baselines.

Most of this is not political. It's the way things were done before the climate started changing so rapidly.
Title: Re: Global sea ice area and extent data
Post by: harpy on February 11, 2018, 08:15:23 PM
The climate started to change rapidly beginning in mid 1900s.  Using incredibly misleading baselines of 1980-2010 is nothing more than delusion, and is purely deception.

Using a 1980-2010 baseline right now to claim that we're currently at less than 1C above baseline is the equivalent of the below analogy:

That's like having a body temperature of 104, and using your temperatures YESTERDAY when your body temperature was 102 as baseline.  Sure, a 2F increase in body temperature in a day is alarming, but when you compare that to a 5F increase from your actual baseline, it's time to get to a hospital ASAP.

Pure delusion at this point. 

NASA knows that 1980-2010 is not the baseline, they use it for political reasons.  There's perfectly good data available pre 1950, but they choose not to use it because EVERYTHING would be significantly above average and the common people would start scratching their heads and wondering.

So long as they use the 1980-2010 baseline, everyone just keeps going to work, keeps buying stuff, keeps having children, keeps pretending that everything is just slightly above average.

Title: Re: Global sea ice area and extent data
Post by: Ktb on February 11, 2018, 09:59:13 PM
On topic please!
Title: Re: Global sea ice area and extent data
Post by: Iceismylife on February 11, 2018, 11:02:28 PM
<snip>

There's a reason why measuring is kept at 1900+. The little ice age. https://en.m.wikipedia.org/wiki/Little_Ice_Age

Temps were already naturally down, so measuring from them would be anomalous.
<snap>
sorry for off topic I'll keep it short.

IMHO The end of the little ice age was the soot addition into the sea ice from the start of the industrial revolution. That would be ~1700.  The feedback loops we are seeing now in the Arctic would've been playing out on the edge of the sea ice 35 miles north of the coast of Denmark. 
Title: Re: Global sea ice area and extent data
Post by: Neven on February 11, 2018, 11:11:49 PM
On topic please!

Yes! Show some respect for the new lowest global sea ice extent minimum on record!  :P

Any off-topic comments in this thread will be deleted for a while to come.
Title: Re: Global sea ice area and extent data
Post by: Iceismylife on February 11, 2018, 11:27:12 PM
Record low NSIDC, who's got the champagne? Gotta celebrate even though it is similar to those depressing movies where a kid throws a birthday party and nobody shows up.
So...yay? :-\
A moment of silence for the new minimum.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 12, 2018, 11:42:58 AM
FROM JAXA DATA AS AT 11 FEB - Global Extent  15,604,595 km2.

On 9th Feb while the JAXA website was on holiday, global extent dropped to  15,550,781 km2, some 53,814 (Correction -) 36,831 km2 less than 2017's record low on 11th Feb.

Since then extent has risen. there are (average last 10 years) 3 days (from zero to 12), 1.3%, 120,000 km2 extent loss to go, or that could be the end of the extent loss period.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 12, 2018, 03:15:55 PM
NSIDC Data updated. They made some changes to previous days extents. The result is that on 10th February global extent was exactly 16.000 million km2. Will this be the record low ?(extent on 11th Feb up by 126 k km2).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 13, 2018, 10:59:28 AM
JAXA extent as at 12th Feb  15,586,027 km2, down 18,568 km2,  just 1,585 km2 below the 2017 minimum. For 3 out of the last 4 days 2018 has been at a record low.

There are on average just 2 more days to go before minimum, with perhaps another 100,000 extent loss. With Arctic Sea Ice gains low or negative and high Arctic temperature anomalies expected at both ends of the CAB, this could be extended a few days.

The fat lady has not sung yet?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 13, 2018, 12:28:15 PM
Forgot to add the graph and tables.

the red coloured boxes in the first table highlight those years where minimum has already passed.

the second table shows the extent to which both 2017 and 2018 are completely outside the range of previous years. As I've said before, one year may be dismissed as an outlier, two years in a row may be the start of a trend.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 14, 2018, 10:00:28 AM
FROM JAXA DATA AS AT 13 FEB - Global Extent   15,607,331  km2.

On 9th Feb global extent dropped to it's lowest to date, 15,550,781 km2, some 36,831 km2 less than 2017's record low on 11th Feb.

Since then extent has risen, due to small increases in Arctic extent and low decreases in Antarctic extent. There is (average last 10 years) just 1 day (from zero to 10), 1.1%, 100,000 km2 extent loss to go, or that could be the end of the extent loss period.

The first table now shows its limitations, basically of little use while extent is above its minimum. Time to look at Sept/Oct minimum and Oct/Nov maximum? Wait a few days, methinks. 
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 14, 2018, 03:13:40 PM
NSIDC daily extent data for 13th Feb

Extent 16.031 million km2, down 72 k
Arctic down 16 k, Antarctic down 56k.

That's seven days 2018 daily extent has been below the 2017 record low - not by a lot, but less.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 15, 2018, 01:01:05 PM
FROM JAXA DATA AS AT 14 FEB - Global Extent 15,634,526  km2, up 33k on the day and now 52k above the minimum to date on 9th Feb.

There is (average last 10 years) zero days (max 9 days), 0.9%, 84,000 km2 extent loss to go. But unless there is an oddity (e.g. a big Arctic drop) methinks that might be it. So the first table will be put on the shelf until late in the year unless something happens. Also note from the graph how last year extent gain was very low in the next month.

What next ? A first look look at the Oct/Nov maximum is posted below.
Title: Re: Global sea ice area and extent data
Post by: Sigmetnow on February 15, 2018, 07:31:39 PM
“Our planet reached another miserable milestone earlier this week: Global sea ice fell to its lowest level since human civilization began more than 12,000 years ago. ”
https://mobile.twitter.com/ericholthaus/status/964184575822921731
Image and link below.

SNAP, CRACKLE, DROP
Polar ice is lost at sea
https://grist.org/article/polar-ice-is-lost-at-sea/ 
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 16, 2018, 12:25:44 PM
FROM JAXA DATA AS AT 15 FEB - Global Extent  15,651,409  km2, up 11k on the day and now 64k above the minimum to date on 9th Feb.

On average (last 10 years) the season is over,  methinks that might be it. The extent on 15th Feb was 253 k below the 2017 extent on that date due to 134k increase in 2017. But note from the graph how last year extent gain was very low in the next month.

What next ? Still a chance that Arctic extent could drop sharply over the next few days. The fat lady may not have yet sung the last chorus.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 16, 2018, 02:04:33 PM
NSIDC daily extent data for 15th Feb

Extent 16.031 million km2, up 23k on the day (not a lot).
Arctic up 22 k, Antarctic up 1 k.

That's 9 days in a row 2018 daily extent has been below the 2017 record low - not by a lot, but less. And more significantly, global extent on 15th Feb 2018 0.331 million less than 2017 extent on that day.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 17, 2018, 01:28:16 PM
And here is JAXA's graph for global extent since 1978.

What the image tells me is how for many years extent was in a tight pack. The bottom two lines are 2017 and 2018. So much farther apart from the pack. This separation started in October 2016 and has never really stopped.

Although Jaxa data has only one day with 2018 extent at a record low, of perhaps greater significance is that for 11 days this year it has been lower than the 2017 daily extent (on 16th Feb 287K less than the 2017 extent on that date.

As always, what happens next? Flash in the pan? or the start of a new trend? or gradual decline resumes ?
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on February 17, 2018, 02:39:12 PM
<snip>


Any off-topic comments in this thread will be deleted for a while to come.

Title: Re: Global sea ice area and extent data
Post by: liefde on February 17, 2018, 03:42:37 PM
<snip>
Title: Re: Global sea ice area and extent data
Post by: Shared Humanity on February 17, 2018, 03:53:46 PM
<snip>
Title: Re: Global sea ice area and extent data
Post by: liefde on February 17, 2018, 10:04:02 PM
NASA knows that 1980-2010 is not the baseline, they use it for political reasons.
Hmm.. I doubt it. The bad thing is, if even that baseline shows anomalies 8 years later, it proves in how much trouble we are, since that means nothing more or less than exponential rise.
Which is exactly what it reveals.
Climate Reanalyzer, for one, uses a 1979-2000 climate baseline (for their 2m T anomaly maps), derived from the reanalysis of the NCEP Climate Forecast System (CFSR/CFSV2). This baseline is chosen over the more typical 1981-2010 climate normal for the simple reason that it better approximates historical climatology. 
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 18, 2018, 05:02:44 PM
JAXA on holiday today (they say maintenance. Huh)

NSIDC daily extent data for 17th Feb 16.031 million km2 , bouncing around at the bottom

That's 11 days in a row 2018 daily extent has been below the 2017 record low - not by a lot, but less. And more significantly, global extent on 17th Feb 2018 is 0.481 million less than 2017 extent on that day. That is a lot.

A table on events in the last 10 days attached, and of course that graph.
Title: Re: Global sea ice area and extent data
Post by: harpy on February 18, 2018, 06:21:06 PM
<snip>
Title: Re: Global sea ice area and extent data
Post by: prairiebotanist on February 18, 2018, 06:34:40 PM
<snip>
Title: Re: Global sea ice area and extent data
Post by: harpy on February 18, 2018, 07:02:39 PM
<snip>

I was just responding to a post, am I not allowed to do that?  Should I just send posts directly to the users?

I'm just trying to figure out how the format works here.

<edit Neven: When I warn that I'm going to delete off-topic comments for a while (because things get out of hand), it's better not to write off-topic comments. Invite others to go to more appropriate threads, which you can either search or open yourself.>
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 20, 2018, 11:08:57 AM
FROM JAXA DATA AS AT 19 FEB - Global Extent   15,648,652  km2, -322,949 km2 less than 2017 on that day.

Methinks the season is over. So here is a table showing how the minimum of 15.55 on the 9th Feb compared with previous years, the graph on where we are, and a first look at the Oct/Nov maximum. ( Note that it was in 2016 that the maximum hit a low low maximum)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 20, 2018, 03:47:47 PM
NSIDC Data as at 19th February Global Extent 16.191million Km2, Arctic up 85k, Antarctic 18k. Lower than 2017 by 337k, (previous day was 437k), but still the 13th day at a record low.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 21, 2018, 01:42:26 PM
JAXA Data as at 20th February Global Extent  15,709,074 million Km2, up 60k.
Lower than 2017 by 267k, (previous day was 323k).

Now looking forward at 2 events,
- the Aug / Sep minimum,
- the Oct / Nov maximum.

too early to make any comments.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 23, 2018, 02:07:46 PM
Global Extent is going up - mostly because of above average increase in the Arctic sea ice extent.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 26, 2018, 05:27:31 PM
NSIDC Data 25th Feb

Global extent still less than 2017. That's quite a few days.
Title: Re: Global sea ice area and extent data
Post by: Ktb on February 26, 2018, 10:45:32 PM
~2 weeks scraping the bottom of the barrel
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 28, 2018, 02:19:00 PM
NSIDC Daily Extent Data 27th Feb - Global extent 16.393 million km2, 106 k Greater Than 2017 (first time for a good few days).

Extract from Wipneus' graph attached

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 01, 2018, 12:58:59 PM
JAXA Data as at 28th February Global Extent   16,135,063 km2, up 100k. 2018 overtook 2017 extent on 26th Feb, and is now 234k greater than 2017. Extent gain since minimum has been 0.58 million km2, compared with the 10 year average of 0.47 k.

This is due to larger than average extent increases at both poles. Table attached looking forward to the Oct/Nov maximum - far too early to make comments.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 01, 2018, 01:54:42 PM
NSIDC Daily Extent data at 28th Feb - table attached. Confirms JAXA trends
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 03, 2018, 12:00:34 PM
And then JAXA produces a surprise, a 17K drop on March 2nd to  16,194,553 km2, from a 5k increase in Antarctica and a 22k drop in the Arctic. 2018 extent is 257k above 2017, but 1.17 million below the 2010's average.


Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 03, 2018, 02:28:48 PM
NSIDC Extent 2nd march also shows a drop
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 04, 2018, 02:49:12 PM
NSIDC 3rd March. Arctic down but Antarctic up more
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 05, 2018, 02:54:33 PM
NSIDC DAILY DATA at 4th March

Arctic down 2k, Antarctic up 5k.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 10, 2018, 02:01:32 PM
NSIDC DAILY DATA at 9th March

and https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_extent_byyear_b.png?attachauth=ANoY7cql91hHLkwhjd8elE-dSxMxj5xmzEyMfLxThlgyPnaUUIMJKS06dxAiHsNshf5gYC7tG0Hei8DgQcOMxaF4TjZPzdCi_1v7oa6l43KtvJBT0hTiRO8rXGUpSBnB1HQFY1BNSSEejIMkwtLgcfEJbwEVmlQgTKHBjVvH3cGLMPcReP5VRhP7kzhiuVQvXaLfvcpotjuYQBTaoShtRE6b7NZlcLrdnKn8d9igMUmBCmrWDnQ67pbjk-y1AmKupEj0ZGU2H2tUM-Kfxhusg3w5vYTG_Xj_07wKAyz1ssedyAbn3ykm9vg%3D&attredirects=0

Strong increases in extent continue - from both Arctic and Antarctic

(Note: JAXA on holiday today)

Title: Re: Global sea ice area and extent data
Post by: colchonero on March 13, 2018, 08:22:39 PM
Very big increases over the last few days.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 14, 2018, 10:04:42 AM
JAXA DATA AS AT 13TH MARCH Extent 17,190,450 km2, some 819 k greater than 2017 on that date. Record lows feel but a distant memory.

Extent gain from minimum is 310k greater than average, reflecting relatively high daily increases in both hemispheres.



Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 14, 2018, 01:19:26 PM
NSIDC DAILY DATA at 13th March

and https://sites.google.com/site/arctischepinguin/home/global-sea-ice

The table and graph say it all.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 18, 2018, 02:09:40 PM
NSIDC DATA AS AT 17TH MARCH Extent 17.989 million km2, some 1.053 million km2 greater than 2017 on that date. Near record lows feel but a very distant memory, but just 11 days ago on 6th March difference with 2017 was 0.093 million km2.

Title: Re: Global sea ice area and extent data
Post by: Dharma Rupa on March 18, 2018, 04:10:31 PM
Feels like last Summer finally (and suddenly) petered out on roughly day 60.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 24, 2018, 02:56:12 PM
Feels like last Summer finally (and suddenly) petered out on roughly day 60.

Didn't it just.

NSIDC data and graph 23 March below
Title: Re: Global sea ice area and extent data
Post by: Tor Bejnar on March 24, 2018, 11:23:43 PM
See, the problem appears to be going away.  At the current rate, we'll have maximum global ice later this year.   ::) :P
But i do not expect the current rate of 'overtaking' previous year's 'current day' values to continue very long.  It appears the NH melting might accelerate earlier than previous years (soon), dampening whatever ice growth happens in the SH.
Title: Re: Global sea ice area and extent data
Post by: Archimid on March 25, 2018, 01:51:06 AM
Although I don't follow Antarctic sea ice as closely as I follow the arctic, my bet is that record high Antarctic sea ice will return soon. I think that when the Arctic is ice free there will be record antarctic growth. I really can't justify that belief.
Title: Re: Global sea ice area and extent data
Post by: oren on March 25, 2018, 08:57:33 AM
Now would be a good time for a gentle reminder that the global sea ice metric is not really that interesting scientifically. Antarctic sea ice extent is highly variable, with a huge max to min range.  And it has a glaciated continent right in the middle. Hansen's predictions are that when the glaciers melt, sea ice will actually grow due to freshening of the top layer of the southern ocean. And this sea ice growth could actually increase glacial melt as it keeps a lid on the ocean and helps increase the temperature of the water lapping at the marine glaciers. So the metric will fare fine while SLR is accelerated.
In addition, antarctic sea ice at maximum (=zero insolation) is no replacement for arctic sea ice at minimum (=high insolation). Again, poor metric.
In my view, this metric has always been the denier's trick, but when it suddenly turned on its head two years ago it was "on our side". I admit it was nice when Wipneus' chart made the rounds. Now this metric might be going back. But it still doesn't change the fundamental fact that it's simply not a good scientific metric.
Title: Re: Global sea ice area and extent data
Post by: Sleepy on March 25, 2018, 10:20:00 AM
Adding that Antarctic sea ice extent was highly variable even in the 60's:
https://earthdata.nasa.gov/new-data-from-old-satellites-a-nimbus-success-story (https://earthdata.nasa.gov/new-data-from-old-satellites-a-nimbus-success-story)
Quote
“We were shocked by what we discovered in these images,” says Gallaher. “We thought, OK, all reports from the 1960s were that it was colder, so we expected to see a lot more sea ice. In fact, 1964 was the largest sea ice extent until 2014. Then in 1966 we saw the lowest ice extent that was ever seen. This was totally unexpected. There’s a lot more variability in sea ice extent than we ever could have imagined.”
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 25, 2018, 10:47:17 AM
Data does not request to be a good scientific metric - it simply is.

Yes, Antarctic Sea Ice varies enormously in extent - and this has corresponding high impacts on insolation and why does it switch so violently?

Ok, and the Sea ice surrounds a continent with about 90% of the world's fresh water on top of it.
And yes, Hansen's predictions are that when the glaciers melt, sea ice will actually grow due to freshening of the top layer of the southern ocean. And this sea ice growth could actually increase glacial melt as it keeps a lid on the ocean and helps increase the temperature of the water lapping at the marine glaciers. But this is speculation? hypothesis?

We know more and more about the Northern Hemisphere cryosphere, and the comparison with our lack of knowledge of the Southern Hemisphere cryosphere (and the oceans) gets more and more extreme even as we know that in the long-term Antarctica and the Oceans may well be the real drivers of our climate.

So ignoring Antarctic Sea Ice data as not a good metric seems a bit odd. Unconscious bias to select  data that is a good metric for the opinions of those on ASIF?
Title: Re: Global sea ice area and extent data
Post by: oren on March 25, 2018, 11:44:32 AM
A. Hansen's is published research, not mere speculation or hypothesis. I can't find the link atm but it's here on the site and was discussed ad nauseum in a dedicate thread.
B. I'm not saying Antarctic sea ice extent isn't a good metric. I am saying bunching it together with arctic sea ice, though they are of opposite seasons by definition, to create Global sea ice extent, is not a good metric.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 25, 2018, 12:03:03 PM
A. Hansen's is published research, not mere speculation or hypothesis. I can't find the link atm but it's here on the site and was discussed ad nauseum in a dedicate thread.
B. I'm not saying Antarctic sea ice extent isn't a good metric. I am saying bunching it together with arctic sea ice, though they are of opposite seasons by definition, to create Global sea ice extent, is not a good metric.
My understanding was that the field data about the Antarctic was extremely limited - so while Hansen (and other scientists) are able to produce predictions based on closely worded argument and mathematics, testing these predictions against field data was a big problem.

Even Einstein had to wait for the eclipse of the Sun and the better astronomical instruments then available before he could demonstrate that gravity bent light and from that the theory of relativity was tested against real world data.

I would not be surprised if Hansen in his paper or abstract made an impassioned plea for more resources to get the data ? Meanwhile here is my data.

JAXA GLOBAL EXTENT AS AT 24 MARCH

The increases since minimum are nearly all down to the Antarctic. I have seen no convincing explanation of these radical changes in recent years that is backed by data. Vague references to the PDO etc but nothing to get hold of and try to understand.
Title: Re: Global sea ice area and extent data
Post by: oren on March 25, 2018, 12:07:45 PM
Gerontocrat, don't take me wrong. First, I agree with what you say, there's a lot of unknown about Antarctic sea ice, and Hansen is not a prophet. And I do look in this thread mostly every day out of curiosity anyway... in spite of my scientific misgivings.
Title: Re: Global sea ice area and extent data
Post by: Sleepy on March 25, 2018, 03:14:47 PM
The recovered Nimbus data covers both poles. The link to the paper can also be found here:
https://forum.arctic-sea-ice.net/index.php/topic,904.msg36905.html#msg36905 (https://forum.arctic-sea-ice.net/index.php/topic,904.msg36905.html#msg36905)
There are posts about the Hansen paper all over but Lennart van der Linde was probably the first poster in the Sea Level Rise and Social Cost of Carbon thread in 2015, then Sigmetnow started the dedicated thread, Hansen et al paper: 3+ meters SLR by 2100. Both under Consequences.

And here's the link:
https://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016-discussion.html (https://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016-discussion.html)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 25, 2018, 03:32:51 PM
Gerontocrat, don't take me wrong. First, I agree with what you say, there's a lot of unknown about Antarctic sea ice, and Hansen is not a prophet. And I do look in this thread mostly every day out of curiosity anyway... in spite of my scientific misgivings.

Sorry about the crabby tone of my post. Having a crabby day. Sometimes I think the concentration on Arctic Sea Ice (and yes, I know it is the Arctic Sea Ice Forum) could be like looking out left and right for traffic while the truck out of control is coming up the rear.

When my brain comes to rest I will have to have another read of Hansen's stuff,  and also look at all the new data - e.g.s the astonishing depth of bedrock being shown on the new maps, the evidence for relatively warm water at considerable depth gnawing away at the glaciers from below (which might make the assumption that the circumpolar vortex stops ocean heat heading South at least partly invalid?) .......
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 05, 2018, 03:28:36 PM
JAXA DATA AS AT 4 April 2018

Since my last post on 24th March data, what a difference. Antarctic extent gain well below average and Arctic sea ice extent at a new record low for the date has made a new record low global maximum a real possibility. (and another week could change it all back again).

On 24th March global extent was 1.4 million greater than 2017, now it is 0.8 million.
Title: Re: Global sea ice area and extent data
Post by: Archimid on April 06, 2018, 02:42:59 AM
I'm glad to see you up and running again gerontocrat.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 06, 2018, 04:44:49 PM
I'm glad to see you up and running again gerontocrat.

Me 50%, Technology 25%.

NSIDC Daily Extent Data 5 April

The attached table shows how 2018 global sea ice extent maxed out at 1.5 million km2 greater than 2017 on 26th March and how in the 10 days since then the difference has shrunk to 0.6 million km2.

This could go into reverse just as quickly or the low Antarctic increases could be matched by persistent Arctic decreases.
Title: Re: Global sea ice area and extent data
Post by: Ktb on April 07, 2018, 02:14:56 PM
Another ~7 days of this and 2018 would be pushing for 1st lowest once again.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 13, 2018, 02:29:45 PM
NSIDC DATA AS AT 12 APRIL

(JAXA is on holiday today)

2017's extent above 2017 has gone down from 1.5 million on 26 March to 0.6 million km2 on 12 April. Extent is on a par with 2006 (a very low extent year).

Graph from https://sites.google.com/site/arctischepinguin/home/global-sea-ice
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 14, 2018, 11:31:28 AM
JAXA DATA AS AT 13 APRIL  18,978,219 KM2

Extent gain continues well below average.
2018 now just 0.77 million km2 greater than 2017.
On average 41% of extent gain done.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 17, 2018, 11:19:53 AM
JAXA DATA AS AT 16 APRIL  19,058,671  KM2

Extent gain continues well below average.
2018 now just 0.53 million km2 greater than 2017.
On average 44% of extent gain done.

The data history suggests a second lowest November maximum is likely, though getting lower than the 2016 maximum looks unlikely.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 19, 2018, 11:17:34 AM
JAXA DATA AS AT 18 APRIL  19,096,469  KM2
Extent gain continues well below average. On 18th April was an extent reduction of 11k, and extent gain to date since the minimum is 530,000 km2 less than the average of the last 10 years. In addition, during this period in 2017 extent gain was greater than average.

As a result 2018 is now just 0.44 million km2 greater than 2017, compared with a maximum of 1.44 million on 27th March.

On average 46% of extent gain done. The historical data  suggests a second lowest November maximum is likely of around 24 million.
Title: Re: Global sea ice area and extent data
Post by: Ktb on April 20, 2018, 08:39:16 AM
Global area once again threatening to be lowest on record
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 20, 2018, 09:44:57 AM
JAXA DATA AS AT 19 APRIL - EXTENT  19,087,420  KM2

What a difference even one day can make. On 18 April 2018 was 0.44 million km2 greater than 2017, on the 19th April 0.33 million km2, (compared with a maximum of 1.44 million on 27th March).

The graph shows well the contrast between what is happening at the moment compared with "normal".
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 20, 2018, 02:30:31 PM
NSIDC DATA says the same

closing on 2017 very quickly.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 21, 2018, 09:00:26 AM
JAXA DATA AS AT 20 APRIL - EXTENT 19,104,604   KM2

I was not expecting to post every day at this time of year, but the data is changing significantly every day.  What a difference even one day can make.
On 18 April 2018 extent was 0.44 million km2 greater than 2017, on the 19th April 0.33 million km2, and on the 20th April 0.21 million km2, (compared with a maximum of 1.44 million on 27th March). Extent gain from minimum is 0.68 million (15%) less than the average of the last ten years..

The graph shows well the contrast between what is happening at the moment compared with "normal".
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 21, 2018, 03:34:33 PM
NSIDC GLOBAL daily EXTENT AS AT 20 APRIL 2018 19.886 million km2

Just a mere 6k increase. See the graph!
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 22, 2018, 02:46:29 PM
NSIDC GLOBAL daily EXTENT AS AT 21 APRIL 2018 19.934 million km2

Now only 0.232 million km2 above 2017 extent (down another 100k)
Title: Re: Global sea ice area and extent data
Post by: Neven on April 22, 2018, 08:32:12 PM
Area seems to be lowest on record:
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 23, 2018, 01:12:31 PM
JAXA DATA AS AT 22 APRIL - EXTENT 19,225,891 KM2

Daily increases going up over the last 2 days, however 2018 extent is now reduced to 0.17 million km2 greater than 2017 - down from 0.22 million on 20 April. It looks more likely than not that 2018 extent will become lowest by the end of the month.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 23, 2018, 03:12:02 PM
NSIDC GLOBAL daily EXTENT AS AT 22 APRIL 2018 19.865 million km2

Now only 0.135 million km2 above 2017 extent (down another 100k)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 24, 2018, 02:34:41 PM
NSIDC GLOBAL daily EXTENT AS AT 23 APRIL 2018  19.952 million km2

Now only 0.087 million km2 above 2017 extent (down another 47 k)
Title: Re: Global sea ice area and extent data
Post by: Neven on April 24, 2018, 03:11:18 PM
Area clearly lowest now:
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on April 24, 2018, 04:35:50 PM
*** Flashbacks from 1998...***  Sorry, I don't know what that was.

But, that global graph looks like the freezing over on southern ocean and melting of ice in northern ocean do not work as they used to.
Title: Re: Global sea ice area and extent data
Post by: Buddy on April 24, 2018, 05:04:36 PM

Quote
But, that global graph looks like the freezing over on southern ocean and melting of ice in northern ocean do not work as they used to.

I certainly can't disagree with that....

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 25, 2018, 11:19:18 AM
JAXA DATA AS AT 24 APRIL - EXTENT  19,392,904 KM2

Daily increases a bit above average due to low extent loss in the Arctic, but arewell below 2017.  , 2018 extent is now reduced to 0.15 million km2 greater than 2017 - It looks more and likely than not that 2018 extent will become lowest by the end of the month.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 26, 2018, 08:23:37 AM
JAXA DATA AS AT 25 APRIL - EXTENT   19,419,695  KM2

Daily increases return to below average, and below half that of 2017.   2018 extent is now 0.087 million km2 above 2017 compared with 1.438 million km2 on the 27th March.  It looks more and likely than not that 2018 extent will become lowest in the satellite record by the end of the month.
[/quote]
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 27, 2018, 11:35:21 AM
JAXA DATA AS AT 26 APRIL - EXTENT  19,419,695  KM2

Daily increases remain well below average, and actually reduced by 1,513 km2 on the 26th.   2018 extent is now 7,395 km2 below2017 compared with 1.438 million km2 above on the 27th March. 

On average, extent gain is 50% complete. A record low maximum is definitely a possibility. That the maximum will be amongst the lowest in the satellite record seems almost inevitable. (Another hostage to fortune?)

Interesting times.
Title: Re: Global sea ice area and extent data
Post by: charles_oil on April 27, 2018, 12:31:31 PM
Gero.. your graph in the above post is quite hard to read - could 2018 be highlighted (bold / dashed maybe) or could the one from 26th be used (less individual years)?   Thanks for keeping these coming in!
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 27, 2018, 12:36:40 PM
Quote
Posted by: charles_oil
« on: Today at 12:31:31 PM » Insert Quote
Gero.. your graph in the above post is quite hard to read - could 2018 be highlighted (bold / dashed maybe) or could the one from 26th be used (less individual years)?   Thanks for keeping these coming in!

JAXA Graphs are a bit of a pain to work with.  Might do my own to match the daily extent change graph.
Title: Re: Global sea ice area and extent data
Post by: HapHazard on April 28, 2018, 10:16:30 AM
Gero.. your graph in the above post is quite hard to read - could 2018 be highlighted (bold / dashed maybe) or could the one from 26th be used (less individual years)?   Thanks for keeping these coming in!

Yeah, it's kinda cluttered - took me a bit to find the 2018 track. I took the liberty of doing a quick edit to help out, though:

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 28, 2018, 02:17:35 PM
NSIDC GLOBAL daily EXTENT AS AT 27 APRIL 2018  20.289 million km2

Now 0.017 million km2 below 2017 extent (cf with 1.467 million km2 above 2017 on 26th March)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 29, 2018, 02:55:37 PM
NSIDC GLOBAL daily EXTENT AS AT 28 APRIL 2018  20.307 million km2

Now 0.063 million km2 below 2017 extent (cf with 1.467 million km2 above 2017 on 26th March)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 01, 2018, 03:49:11 PM
NSIDC GLOBAL daily EXTENT AS AT 30 APRIL 2018  20.307 million km2

Now 0.065 million km2 below 2017 extent (cf with 1.467 million km2 above 2017 on 26th March)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 03, 2018, 03:30:35 PM
JAXA DATA - Extent as at 2 May =  19,924,895 km2, 109k above 2017

On average, a maximum of 24 million km2, second lowest, is on the cards.
On average, 55% of extent gain done, but with 6 months to go.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 09, 2018, 02:36:10 PM
JAXA DATA - Extent as at 8 May =   20,346,216 km2, 73k above 2017

On average, a maximum of 24 million km2, second lowest, is on the cards, with a relatively low range of 23 million to 25.2 million outcomes from the last 10 years remaining extent gain.
On average, 59% of extent gain done, but with 6 months to go.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 09, 2018, 06:53:47 PM
NSIDC Global Extent as at 8 May 20.88 Million Km2, 0.2 million Km2 below 2017

Interesting difference with JAXA.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 11, 2018, 11:10:27 AM
JAXA DATA - Extent as at 10 May =    20,375,167 km2, 110k below 2017

In the last two days above average extent loss in the Arctic and below average extent gain in the Antarctic has meant that global extent gain has stalled.

On average, a maximum of 24 million km2, second lowest, is on the cards, with a relatively low range of 23 million to 25 million km2 outcomes from the last 10 years remaining extent gain.
On average, 60% of extent gain done, but with 6 months to go.
Title: Re: Global sea ice area and extent data
Post by: kiwichick16 on May 11, 2018, 11:26:48 PM
la nina/ neutral year .....yet again flirting with lowest on record levels .....Miocene here we come?
Title: Re: Global sea ice area and extent data
Post by: jdallen on May 12, 2018, 06:49:44 PM
la nina/ neutral year .....yet again flirting with lowest on record levels .....Miocene here we come?
That's on my mind as well.  I will hasten to add that 2010, 2011 and 2012 were La Nina years.
Title: Re: Global sea ice area and extent data
Post by: litesong on May 12, 2018, 08:46:14 PM
la nina/ neutral year .....yet again flirting with lowest on record levels .....Miocene here we come?
That's on my mind as well.  I will hasten to add that 2010, 2011 and 2012 were La Nina years.
Its best to consider that the solar TSI has been languid for 50 years & low for 11+ years (including a 3+ year period, setting a 100 year record low radiation level). Yet, global sea ice continues near its least quantities.
Title: Re: Global sea ice area and extent data
Post by: kiwichick16 on May 13, 2018, 03:35:20 AM
Historical reconstruction of  TSI

http://lasp.colorado.edu/home/sorce/files/2011/09/TIM_TSI_Reconstruction-1.png
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 13, 2018, 12:06:14 PM
JAXA DATA - Extent as at 12 May =     20,498,076  km2, 166k below 2017

In the last two days above average extent loss in the Arctic but above average extent gain in the Antarctic has meant that global extent gain has increased again.

On average, a maximum of 24 million km2, second lowest, is on the cards, with a relatively low range of 23 million to 25 million km2 outcomes from the last 10 years remaining extent gain.
On average, 61% of extent gain done, but with 6 months to go.

ps:- Due to the different timings of Antarctic gain and Arctic loss, there is a secondary minimum of global extent in late August or September. At the moment, this also looks like a record low is very possible. See last table attached.
Title: Re: Global sea ice area and extent data
Post by: josh-j on May 13, 2018, 02:35:56 PM
Quote from: litesong
Its best to consider that the solar TSI has been languid for 50 years & low for 11+ years (including a 3+ year period, setting a 100 year record low radiation level). Yet, global sea ice continues near its least quantities.

Forgive the straying off topic but just one question for litesong - I don't see a languid 50 years in kiwichick's link. But I don't know much about the subject; could you link your source?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 19, 2018, 01:08:53 PM
JAXA DATA - Extent as at 18 May =      21,044,896 km2, 67k below 2017


On average, a maximum of 24.25 million km2, a bit higher but still second lowest, is on the cards, with a relatively low range of 23 million to 25 million km2 outcomes from the last 10 years remaining extent gain.
On average, 65% of extent gain done, but with 170 days to go.

ps:- Due to the different timings of Antarctic gain and Arctic loss, there is a secondary minimum of global extent in late August or September. At the moment, this also looks like a record low is very possible. See last table attached.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 19, 2018, 02:06:26 PM
NSIDC Global Extent as at 18 May 21.195 Million Km2, 0.284 million Km2 below 2017

Graph from https://sites.google.com/site/arctischepinguin/home/global-sea-ice


Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 23, 2018, 08:27:56 PM
NSIDC Global Extent as at 22 May 22.064 Million Km2, 0.079 million Km2 above 2017

Strong sea ice gain in the Antarctic has changed the picture somewhat.

Graph from https://sites.google.com/site/arctischepinguin/home/global-sea-ice
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 25, 2018, 02:18:10 PM
NSIDC Global Extent as at 24 May 22.012 million km2, 0.189 million Km2 below 2017

Sea ice gain in the Antarctic sort of stopped and changed the picture again.

Graph from https://sites.google.com/site/arctischepinguin/home/global-sea-ice
Title: Re: Global sea ice area and extent data
Post by: Ktb on May 25, 2018, 02:32:00 PM
Gerontocrat, do you know the total number of days 2018 has spent at the lowest position in global extent?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 25, 2018, 02:41:36 PM
Gerontocrat, do you know the total number of days 2018 has spent at the lowest position in global extent?
34 out of 144, I think.
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on May 25, 2018, 08:54:04 PM
Getting exciting, does it flatline or not?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 28, 2018, 09:33:30 AM
JAXA DATA - Extent as at 27 May = 21,536,004 km2, 18k above2017

On average, a maximum of 24.31 million km2, a bit higher but still second lowest, is on the cards, with a relatively low range of 23.5 million to 25.2 million km2 outcomes from the last 10 years remaining extent gain.
On average, 69% of extent gain done, with 161 days to go.

ps:- Due to the different timings of Antarctic gain and Arctic loss, there is a secondary minimum of global extent in late August or September. At the moment, this also looks like a record low is very possible. See last table attached.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 01, 2018, 11:32:15 AM
JAXA DATA - Extent as at 31 May =  21,863,760 km2, 18k above2017

On average, a maximum of 24.44 million km2, a bit higher but still second lowest, is on the cards, with a relatively low range of 23.7 million to 25.2 million km2 outcomes from the last 10 years remaining extent gain.
On average, 71% of extent gain done, with 157 days to go.

ps:- Due to the different timings of Antarctic gain and Arctic loss, there is a secondary minimum of global extent in late August or September. At the moment, this also looks like a record low is very possible. See last table attached.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 05, 2018, 03:16:13 PM
JAXA DATA - Extent as at 4th June =   22,111,119 km2, 38k below2017 and 34k greater than 2016 - i.e. 2nd lowest by a teeny bit.

On average, a maximum of  24.43 million km2, a bit higher but still second lowest, is on the cards, with a slightly lower range of 23.8 million to 25.1 million km2 outcomes from the last 10 years remaining extent gain.
On average, 74% of extent gain done, with 153 days to go.

ps:- Due to the different timings of Antarctic gain and Arctic loss, there is a secondary minimum of global extent in late August or September. At the moment, this also looks like a record low is very possible. See last table attached.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 08, 2018, 12:37:31 PM
JAXA DATA - Extent as at 7th June =    22,237,997 km2, 145k below2017 and 262k below 2016 - i.e. lowest by a significant bit.

On average, a maximum of  24.39 million km2, a still second lowest, is on the cards, with a slightly lower range of 23.5 million to 25.0 million km2 outcomes from the last 10 years remaining extent gain.
On average, 76% of extent gain done, with 150 days to go.

ps:- Due to the different timings of Antarctic gain and Arctic loss, there is a secondary minimum of global extent in late August or September. At the moment, this also looks like a record low is very possible. See last table attached.
[/quote]
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 10, 2018, 08:50:40 AM
JAXA DATA - Extent as at 7th June = 22,469,175 km2, 30k below2017 and 200k below 2016 - i.e. still lowest- just.

A combination of high Antarctic gains and low Arctic losses over the last three days has changed the picture somewhat.

On average, a maximum of  24.52 million km2, still second lowest, is on the cards, with a slightly lower range of 23.6 million to 25.1 million km2 outcomes from the last 10 years remaining extent gain. To be a record low, remaining extent gain would have to be about 40% less than the average remaining extent gain of 2 million km2.
 
On average, 77% of extent gain done, with 148 days to go.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 14, 2018, 02:02:16 PM
NSIDC Global Daily Extent as at 13th June + Jaxa image (https://ads.nipr.ac.jp/vishop/#/extent/&time=2018-05-29%2000:00:00)

NSIDC and Jaxa extent data show the same story - high Antarctic gains and low Arctic losses.


Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 15, 2018, 11:11:37 AM
JAXA DATA - Extent as at 14th June =  23,085,478 km2, 640k above2017 and 116k below 2016

A combination of high Antarctic gains and low Arctic losses over the last 10 days or so has changed the picture somewhat.

On average, a maximum of  24.94 million km2, 1.2 million km2 above the record low of 2016, still second lowest (just), with a range of 23.7 million to 25.8 million km2 outcomes from the last 10 years remaining extent gain.

A record low is looking about impossible as remaining extent gain would have to be about 70% less than the average.
 
On average, 80% of extent gain done, with 143 days to go.
Title: Re: Global sea ice area and extent data
Post by: Ktb on June 16, 2018, 02:16:33 AM
Global area has managed to punch back into +/-2 standard deviation range for the first time since July 2016.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 18, 2018, 12:43:04 PM
JAXA DATA - Extent as at 17th June =   23,103,875 km2, 457k above 2017 and 200k below 2016

A combination of high Antarctic gains and low Arctic losses over the last 10 days or so changed the picture somewhat and then in the last three days reversed to very low Antarctic gains. 17th June saw a 27k drop in total extent, (a bit earlier than the average year start in early July).

On average, a maximum of  24.82 million km2, 1.1 million km2 above the record low of 2016, still second lowest, with a range of 23.6 million to 25.6 million km2 outcomes from the last 10 years remaining extent gain.

A record low is looking about impossible as remaining extent gain would have to be about 70% less than the average (as happened in 2016).
 
On average, 81% of extent gain done, with 140 days to go.

The last table shows the Sept/Oct "false minimum" caused by the different timing of Arctic extent loss and Antarctic extent gain. A record low is still very possible.
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on June 18, 2018, 12:53:40 PM
No flatline to the summer secondary peak then, still possible to have a flatline in autumn of course.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 02, 2018, 12:54:10 PM
JAXA DATA - Extent as at 1st July 2018 = 23,767,558 km2, 1.130 million km2 above 2017 and 4th lowest in the satellite record

A combination of high Antarctic gains and low Arctic losses in June makes a record low look somewhat unlikely to impossible.

On average, a maximum of  25.38 million km2 is the result from average remaining extent gain, 1.6 million km2 above the record low of 2016. The previous 10 years remaining extent gain gives outcomes ranging from 23.84 to 26.28 million km2..

On average, 82% of extent gain done, with 1 days to go.

The last table shows the Sept/Oct "false minimum" caused by the different timing of Arctic extent loss and Antarctic extent gain. A record low is still just about possible. But note this assumes that as usual for a period of time from about now, daily Arctic Sea Ice extent loss is greater than Antarctic Sea Ice gain, as happened in 2016.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 02, 2018, 12:55:16 PM
And a graph from JAXA.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 08, 2018, 08:59:48 AM
JAXA DATA - Extent as at 7 July 2018 =  23,860,328 km2, 1.024 million km2 above 2017 and 5th lowest in the satellite record

A combination of high Antarctic gains and low Arctic losses in June makes a record low look somewhat unlikely to impossible.

On average, a maximum of  25.52 million km2 is the result from average remaining extent gain, 1.6 million km2 above the record low of 2016. The previous 10 years remaining extent gain gives outcomes ranging from 23.86 to 26.6 million km2..

On average, 82% of extent gain done, with 120 days to go.

At this point in time, Arctic loss is, on average, greater than Antarctic gain. This is not happening so far this year to any meaningful extent.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 17, 2018, 02:25:36 PM
JAXA DATA - Extent as at 16 July 2018 =   23,720,655 km2, 1.116 million km2 above 2017 and 6th lowest in the satellite record

A combination of average Antarctic gains and low Arctic losses in June and July makes a record low look unlikely to impossible, given that extent is now only 40 k below that record.

On average, a maximum of  25.64 million km2 is the result from average remaining extent gain, 1.9 million km2 above the record low of 2016. The previous 10 years remaining extent gain gives outcomes ranging from 23.94 to 26.65 million km2.

On average, 79% of extent gain done, with 111 days to go.

At this point in time, daily Arctic loss is, on average, greater than daily Antarctic gain. This is not happening so far this year to any meaningful extent. (see garph and table re Sept/Oct false minimum)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 17, 2018, 02:27:49 PM
And a graph from JAXA to complete the picture
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 21, 2018, 11:07:25 AM
JAXA DATA - Extent as at 20 July 2018 = 23,533,468 km2, 0.760 million km2 above 2017 and 6th(?) lowest in the satellite record

In recent days high Arctic losses and low Antarctic gains has made a bit of a difference.
On average, a maximum of  25.54 million km2 is the result from average remaining extent gain, 1.8 million km2 above the record low of 2016. The previous 10 years remaining extent gain gives outcomes ranging from 23.88 to 26.33 million km2.

On average, 78% of extent gain done, with 107 days to go.

Table re the Sep/Oct false minimum also attached.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 21, 2018, 11:09:47 AM
And a graph from JAXA.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 28, 2018, 01:39:09 PM
JAXA DATA - Extent as at 20 July 2018 =  23,167,525 km2, now only 0.139 million km2 above 2017 and 2nd(?) lowest in the satellite record

In recent days high Arctic losses and low Antarctic gains has made a large difference.

Looking at the Sep/Oct temporary minimum, if Arctic extent losses continue above average, and Antrctic gains low, a record low temporary minimum is a real possibility.

Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on July 28, 2018, 05:43:45 PM
JAXA DATA - Extent as at 20 July 2018 =  23,167,525 km2, now only 0.139 million km2 above 2017 and 2nd(?) lowest in the satellite record

In recent days high Arctic losses and low Antarctic gains has made a large difference.

Looking at the Sep/Oct temporary minimum, if Arctic extent losses continue above average, and Antrctic gains low, a record low temporary minimum is a real possibility.


Whee!! Where's the heat off, that was redistributed by atmosphere, 2015 El Nino? Has it stayed in south (New Zealand heat in 2016-7), or is there a northern component to it ( like 2 weeks of +30°C weather in northern Europe.)
 On the yard, in the shade, 31 degrees, sweating, having beer. (At least it's windy today. Soon to water the lawn, surprised the city hasn't yet complained of the water usage of the citizens.
Title: Re: Global sea ice area and extent data
Post by: harpy on July 29, 2018, 01:31:29 AM
Record low:

Unlikely to impossible on July 17th.

Real possibility.  July 28th.



Title: Re: Global sea ice area and extent data
Post by: gerontocrat on July 31, 2018, 03:11:54 PM
Record low:

Unlikely to impossible on July 17th.

Real possibility.  July 28th.
As the US SeaBees (Construction Battalion) used to say - "the impossible will take a little longer".

Harpy, you were out by 2 days (NSIDC Daily Extent Data).

https://sites.google.com/site/arctischepinguin/home/global-sea-ice
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on August 07, 2018, 09:45:24 AM
JAXA DATA - Extent as at 6 Aug 2018 =   22,854,878  km2, now 0.349 million km2 above 2017 and 2nd(?) lowest in the satellite record

A mixture of variable gains and losses have kept an unchanged picture. Extent and a likely maximum of around 25 million are well below historical averages for a third year. Three years in a row at least suggest the beginning of a significant change.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on August 11, 2018, 12:10:27 PM
JAXA DATA - Extent as at 10 Aug 2018 =   22,854,878  km2, now 0.327 million km2 (1.4%) above 2017 and 2nd lowest in the satellite record

A bit above average arctic sea ice losses and well below average Antarctic sea ice gains have changed the picture somewhat. Extent is now 856k (3.8%) below the 2010's average.

The September interim minimum from the remaining average net sea ice loss in this period is on 5 Sept, just 27 days from now.  The average result is 21.96 million, just 0.05 million above the record low in 2012 on the 25 August.

But this measure is subject to highly volatile change.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on August 21, 2018, 11:54:15 AM
JAXA DATA - Extent as at 20 Aug 2018 =  22,554,294 km2, now 0.237 million km2 (1.0%) above 2017 and 4th lowest in the satellite record

Extent is now 698 k (3.1%) below the 2010's average.

The September interim minimum from the remaining average net sea ice loss in this period is on 5 Sept, just 17 days from now. However, this minimum could be in 5 days or as many as 31 days from now. The average result is 22.11 million, just 0.20 million above the record low in 2012 on the 25 August.

But this measure is subject to highly volatile change.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on August 29, 2018, 09:49:27 AM
JAXA DATA - Extent as at 28 Aug 2018 =   22,507,019  km2, now 0.180 million km2 (0.8%) above 2017 and 4th lowest in the satellite record

Extent is now 604 k (2.7%) below the 2010's average.

The September interim minimum from the remaining average net sea ice loss in this period is on 5 Sept, just 9 days from now. However, this minimum was reached earlier in 3 years, and could have been reached already, or be in as many as 23 days from now. The average result is 22.27 million, 4th lowest, and 0.36 million above the record low in 2012 on the 25 August. But for the very slow arctic melt this year, a new record low would have been possible.

This measure is subject to highly volatile change, and at this time especially projections of outcomes are of little value.
[/quote]
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on August 29, 2018, 07:17:41 PM
Entering the exiting other season when global ice may flatline. The northern hemisphere heat didn't reach arctic this year but the build-up of new ice may still be slow. Or the antarctic ice might leave fast.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on August 29, 2018, 11:58:18 PM
Entering the exiting other season when global ice may flatline. The northern hemisphere heat didn't reach arctic this year but the build-up of new ice may still be slow. Or the antarctic ice might leave fast.

Having both Arctic and Antarctic to consider gives one double the chances of being wrong. And I should know.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 01, 2018, 12:17:29 PM
JAXA DATA - Extent as at 31 Aug 2018 =    22,471,089  km2, now 0.241 million km2 (1.1 %) above 2017 and 3rd lowest in the satellite record

Extent is now 594 k (2.6%) below the 2010's average.

The September interim minimum is on average on 5 Sept, just 5 days away. However, this minimum was reached earlier in 2011, 2012, and 2014, and could have been reached already, or be in as many as 20 days from now. The result from average further extent loss is 22.29 million, 4th lowest, and 0.38 million above the record low in 2012 on the 25 August. But for the very slow arctic melt this year, a new record low would have been possible.

This measure is subject to highly volatile change, and at this time especially projections of outcomes are of little value.
Title: Re: Global sea ice area and extent data
Post by: Ktb on September 09, 2018, 06:18:01 AM
Big loss in the antarctic today should push global sea ice extent to lowest on record. First time since late July.

Edit: don't ice while intoxicated
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 09, 2018, 09:28:16 AM
JAXA DATA - Extent as at 8 Sep 2018 = 22,240,985 km2, now 96k km2 (0.4 %) below 2017 and 2nd lowest in the satellite record  (45k > 2012 - not quite a record low Ktb)

Extent is now 779 k (3.5%) below the 2010's average.

The September interim minimum was on average on 5 Sept, 3 days before. However, this minimum was reached earlier in 2011, 2012, 2013,2014 and 2017, and could be  be in as many as 12 days from now (2008, 2010). The result from average further extent loss is 22.11 million, just 4th lowest, and 0.20 million above the record low in 2012 on the 25 August. But for the very slow arctic melt this year, a new record low would have been probable.

This measure is subject to highly volatile change, and at this time especially, projections of outcomes are of little value.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 10, 2018, 10:29:38 AM
JAXA DATA - Extent as at 9 Sep 2018 = 22,227,260 km2, now 159k km2 (0.7 %) below 2017 and lowest in the satellite record 

Extent is now 812 k (3.7%) below the 2010's average.

The September interim minimum was on average on 5 Sept,4 days before. However, this minimum was reached earlier in 2011, 2012, 2013,2014 and 2017, and could be  be in as many as 11 days from now (2008, 2010).

The result from average further extent loss is 22.10 million, just 4th lowest, and 0.19 million above the record low in 2012 on the 25 August. But for the very slow arctic melt this year, a new record low would have been probable.

This measure is subject to highly volatile change, and at this time especially, projections of outcomes are of little value.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 10, 2018, 10:32:14 AM
Extract from JAXA Graph attached. Over the coming days, the trend to watch will be against 2016 into 2017, the year in which Antarctic sea ice extent completed the collapse from the record highs of 2013 and 2014.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 10, 2018, 02:58:53 PM
NSIDC Daily Extent Data - Record low by 194k at 22.405 million Km2 on 9th September.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 11, 2018, 02:18:07 PM
JAXA DATA - Extent as at 10 Sep 2018 =  22,174,535 km2, now 259k km2 (1.2 %) below 2017, 57k (0.3%) below 2016 and lowest in the satellite record 

Extent is now 905 k (4.1%) below the 2010's average.

The September interim minimum was on average on 5 Sept, 5 days before. However, this minimum was reached earlier in 2011, 2012, 2013,2014 and 2017, and could be  be in as many as 10 days from now (2008, 2010).

The minimum result from average further extent loss is 22.04 million, 3rd lowest, and 0.13 million above the record low in 2012 on the 25 August. But for the very slow arctic melt this year, a new record low would have been certain.

This measure is subject to highly volatile change, and at this time especially, projections of outcomes are of little value. However, the data does tell us that currently global sea ice is extremely low, and has been for some time. The graphs are impressive.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 11, 2018, 02:20:09 PM
Extract from JAXA Graph attached. Over the coming days, the trend to watch will be against 2016 into 2017, the period in which Antarctic sea ice extent completed the collapse from the record highs of 2013 and 2014.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 11, 2018, 03:52:26 PM
NSIDC Daily Extent Data -  at 22.259 million Km2 on 10th September, Record low by 299k.
[/quote]
Title: Re: Global sea ice area and extent data
Post by: Stephan on September 11, 2018, 08:21:09 PM
The second graph within a few days where the pen is writing its line on previously untouched areas...
Title: Re: Global sea ice area and extent data
Post by: Dharma Rupa on September 11, 2018, 09:42:55 PM
The second graph within a few days where the pen is writing its line on previously untouched areas...

Yes, but with the tendency of North and South to see-saw, if it hard to say exactly what this means.

I guess we can at least say exactly that -- previously untouched.
Title: Re: Global sea ice area and extent data
Post by: DavidR on September 13, 2018, 02:21:09 PM
NSIDC Daily Extent Data -  at 22.259 million Km2 on 10th September, Record low by 299k.
The previous record global low on Sept 10th occurred in 2016 and was just 113 K km^2 above 2018. By the 12th, 2016  is record lowest again by just  26 K km^2.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 16, 2018, 03:25:42 PM
NSIDC GLOBAL Daily Extent Data -  at 22.241 million Km2 on 15th September, a dead heat with 2016.

I have switched the comparison of extent from 2017 to 2016, as we are almost at the time of year when in 2016 Global extent dropped like a stone - very much due to Antarctic melt.
Title: Re: Global sea ice area and extent data
Post by: charles_oil on September 16, 2018, 09:17:23 PM
Ger - any chance you could differentiate 2018 a bit better - dotted / thicker line / contrasting colour ?  Many thanks
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 16, 2018, 09:34:25 PM
Ger - any chance you could differentiate 2018 a bit better - dotted / thicker line / contrasting colour ?  Many thanks
Not my graph! As the name says, it is by Wipneus
Title: Re: Global sea ice area and extent data
Post by: DavidR on September 17, 2018, 06:53:15 AM
Ger - any chance you could differentiate 2018 a bit better - dotted / thicker line / contrasting colour ?  Many thanks
Here's a more focussed look at this month. I  have taken out the years before 2001 but included them in Max Min and Average from 1988 - 2017.  2018 in black 2016 in red.
Title: Re: Global sea ice area and extent data
Post by: charles_oil on September 17, 2018, 09:19:35 AM
Thanks !
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 28, 2018, 10:07:23 AM
JAXA DATA - Extent as at 27 Sep 2018 =   22,746,339  km2,

Extent is
- 830 k (3.6%) below the 2010's average.
- 228k km2 (1.0 %) above 2017,
- 16k km2 (0.1 %) above 2008,
- 184k (0.8%) below 2016 and
- 3rd lowest in the satellite record

There are on average 38 days to maximum. Average remaining extent gain would produce a maximum of 25.11, 2nd lowest in the satellite record. This measure is subject to highly volatile change, and projections of outcomes are of little value. However, the data does tell us that currently global sea ice is extremely low, and has been for some time.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on September 30, 2018, 11:05:58 AM
JAXA DATA - Extent as at 29 Sep 2018 =    22,789,041 km2,

Extent is
- 918 k (4.0%) below the 2010's average.
- 63k km2 (0.3 %) above 2017,
- 154k (0.7%) below 2016 and
- 2nd lowest in the satellite record

While Antarctic ice extent is dithering around the maximum (i.e. melt very slow), Arctic ice extent increase is very slow.

There are on average 36 days to maximum. Average remaining extent gain would produce a maximum of 25.04, 2nd lowest in the satellite record. This measure is subject to highly volatile change, and projections of outcomes are of little value. However, the data does tell us that currently global sea ice is extremely low, and has been for some time.
Title: Re: Global sea ice area and extent data
Post by: GoSouthYoungins on October 01, 2018, 03:34:22 AM
2018 global extent looks set to test the 2016 lows for the rest of the year. Particularly the next 6 weeks will be very interesting.
Title: Re: Global sea ice area and extent data
Post by: Stephan on October 01, 2018, 07:12:56 PM
My guess is that it will follow more likely the 2017 pathway. But let's see what really happens...
Title: Re: Global sea ice area and extent data
Post by: jacksmith4tx on October 01, 2018, 11:50:54 PM
A new visualization tool called PolarGlobe was just released.
https://asunow.asu.edu/20181001-creativity-illustrating-dance-earth
Quote
PolarGlobe is a large-scale, web-based four-dimensional visualization tool allowing climate data access to anyone with an internet connection. It’s capable of illustrating changes in the atmosphere vividly in real time.

Designed specifically for polar scientists seeking to understand the ice caps, the tool is also useful for high school science teachers and weather fanatics.

The technology is called m-cubed: “Multi-dimensional, multi-faceted, multi-variate.”

Historical data in the tool goes back to 2010. Current data is updated every six hours. The tool uses artificial intelligence and machine learning so it continues to learn on its own as new data is generated.

It’s a huge amount of data: 350 terabytes

http://cici.lab.asu.edu/polarglobe/

Maybe someone will find it useful in predicting polar ice conditions.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 03, 2018, 08:39:29 PM
NSIDC GLOBAL Daily Extent Data -  at 23.135 million Km2 on 2nd October

This is a record low (just) due to Antarctic Sea Ice dithering around the maximum and Arctic sea ice gain so far below average.

The time has almost arrived when 2016 Antarctic melt went crazy. What will 2018 do?

ps: The little wobbles in the 1980's line due to my inability to be bothered to smooth out the early years when NSIDC only posted data every 2 days.
Title: Re: Global sea ice area and extent data
Post by: Stephan on October 03, 2018, 10:22:05 PM
Once again the pen draws a line on previously untouched areas of this graph.
The closest years in global SIE are 2017, 2016 and 2012. This is not by chance, but a trend.
I wonder whether SIE loss in the Antarctic will start soon (then we may see a global SIE like 2016) or whether it will be delayed (then the global curve should more look like 2017).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 04, 2018, 09:55:21 AM
JAXA DATA - Extent as at 3 Oct 2018 =     22,783,227 Km2,

Extent is
- 1,087 k (4.8%) below the 2010's average.
- 174k km2 (0.8 %) below 2017,
- 194k (0.8%) below 2016,
- Lowest in the satellite record,
- 6k LESS than extent on 30 September.

Antarctic ice extent is dithering around the maximum though declining in the last 2 days,(i.e. melt very slow), Arctic ice extent increase is still very slow.

There are on average 32 days to maximum. Average remaining extent gain would produce a maximum of 24.83 million km2, 2nd lowest in the satellite record. Higher by just over 1 million  than the 2016 record minimum maximum.

This measure is subject to highly volatile change, and projections of outcomes are of little value. However, the data does tell us that currently global sea ice is extremely low, and has been for some time.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 05, 2018, 09:38:02 AM
JAXA DATA - Extent as at 4 Oct 2018 = 22,795,223 km2   

Extent is
- 1,127 k (4.9%) below the 2010's average.
- 308k km2 (1.3 %) below 2017,
- 280k (1.2%) below 2016,
- Lowest in the satellite record,


Antarctic ice extent, after dithering around the maximum, is now declining , Arctic ice extent increase is still below average.

There are on average 31 days to maximum. Average remaining extent gain would produce a maximum of 24.79 million km2, 2nd lowest in the satellite record. Higher by just over 1 million  than the 2016 record minimum maximum.

This measure is subject to highly volatile change, and projections of outcomes can change greatly in a very few days. However, the data does tell us that currently global sea ice is extremely low, and has been for some time. The last graph makes it obvious that the cryosphere is shrinking.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 05, 2018, 09:43:31 AM
And here is an extract from the JAXA Global Graph, to show that the pen is still writing on the unused part of the paper.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 06, 2018, 07:29:09 AM
And here is an extract from the JAXA Global Graph, to show that the pen is still writing on the unused part of the paper.
Title: Re: Global sea ice area and extent data
Post by: GoSouthYoungins on October 09, 2018, 08:11:47 AM
My guess is that it will follow more likely the 2017 pathway. But let's see what really happens...

I think it is quite likely that we stay in record territory for much of the freezing season (possibly indefinitely). The Laptev Sea is typically experience a rapid freeze during October, but we currently look quite far out from that due to SSTs. As it catches up in November, the Chukchi Sea will be resisting its typically rapid freeze.

Antarctica can always surprise and the Hudson is set up to freeze early, but I think there is a good chance record low is the new normal.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 11, 2018, 07:10:19 PM
JAXA DATA - Extent as at 10 Oct 2018 =  22,912,826 km2   

Extent is
- 1,456 k (6.0%) below the 2010's average.
- 989k km2 (4.1 %) below 2017,
- 132k (0.6%) below 2016,
- Lowest in the satellite record.

Antarctic ice extent, after dithering around the maximum, is now declining but very slowly , Arctic ice extent increase is still below average. Global sea ice extent is at the moment following 2016.

As a result, the pen has written on the unused part of the graph paper for 9 days in a row.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 12, 2018, 09:56:09 AM
As of 11th October Global Sea Ice Extent for the day is no longer the lowest in the satellite record - higher than average extent gain in the Arctic plus an extent gain (instead of loss) in the Antarctic.
Title: Re: Global sea ice area and extent data
Post by: Stephan on October 12, 2018, 05:48:10 PM
This is probably another spike, such of those we see almost every year (see e.g. the green curve for 2017). I guess global sea ice data will return down to record values next week.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 20, 2018, 11:17:32 AM
Global Sea Ice Extent as 19th October   23,640,213 km2

This is
- second lowest in the satellite record,
- 1.423 million km2 (5.7%)  below the 2010's average,
- 0.925 million km2 (3.8%)  below 2017,
- 0.373 million km2 (1.6%)  above 2016 (the record year).

There are on average just 16 days to the maximum, with 91% of the season's extent gain done.
The likelihood from past years is a 2nd lowest maximum.
Title: Re: Global sea ice area and extent data
Post by: Aluminium on October 22, 2018, 12:21:41 AM
More graphs (https://sites.google.com/site/arctischepinguin/home/global-sea-ice). Global extent anomaly descended below -4σ again.
Title: Re: Global sea ice area and extent data
Post by: lurkalot on October 22, 2018, 12:21:51 PM
To my elderly eyes it appears that, in both area and extent, this is likely to be the first time in the satellite record that the autumn local maximum is lower than the summer one. Am I right?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 22, 2018, 01:04:05 PM
To my elderly eyes it appears that, in both area and extent, this is likely to be the first time in the satellite record that the autumn local maximum is lower than the summer one. Am I right?
Looking at JAXA data suggest it will be a close run thing. But what ever happens it looks like the cryosphere continues a downward trend.

On average just 14 days to max (+/- 7 days).
Title: Re: Global sea ice area and extent data
Post by: Ktb on October 22, 2018, 04:35:07 PM
To my elderly eyes it appears that, in both area and extent, this is likely to be the first time in the satellite record that the autumn local maximum is lower than the summer one. Am I right?


Actually 2016 was the first to do this, and did so for both extent and area.
Title: Re: Global sea ice area and extent data
Post by: Stephan on October 22, 2018, 06:29:33 PM
To my elderly eyes it appears that, in both area and extent, this is likely to be the first time in the satellite record that the autumn local maximum is lower than the summer one. Am I right?
Statistically you can expect another fortnight with ever decreasing global sea ice increases. So it may well be that 2018 shares 2016's development. But the variability is high; slower than average melting around Antarctica and higher than average freezing in the Arctic will lead 2018's path more into 2017's direction.
Anyway, the 4 sigma deviation is shocking...
Title: Re: Global sea ice area and extent data
Post by: Wipneus on October 23, 2018, 09:15:22 AM
To my elderly eyes it appears that, in both area and extent, this is likely to be the first time in the satellite record that the autumn local maximum is lower than the summer one. Am I right?


Actually 2016 was the first to do this, and did so for both extent and area.

Actually the first full year in the available series, 1979 was the first. After that no other years until 2016.

Click those attachments for the big view.
Title: Re: Global sea ice area and extent data
Post by: josh-j on October 23, 2018, 09:06:00 PM
Thanks for those charts Wipneus - it's like a once healthy heartbeat suddenly looking dodgy... !
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 25, 2018, 01:02:25 PM
Global Sea Ice Extent as 24th October    23,921,633  km2

This is
- second lowest in the satellite record,
- 1.464 million km2 (5.8%)  below the 2010's average,
- 0.885 million km2 (3.6%)  below 2017,
- 0.394 million km2 (1.7%)  above 2016 (the record year),
- just 22k below the false summer maximum of 23.944 million km2.

In recent days above average Antarctic extent loss was insufficient to offset high Arctic extent gain.

There are on average just 11 days to the maximum, with 95% of the season's extent gain done.
The likelihood from past years is a 2nd lowest maximum about half-way between 2017 (2nd lowest) and 2016 (lowest).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on October 28, 2018, 09:54:43 AM
Global Sea Ice Extent as 27th October 24,444,792 km2

This is
- second lowest in the satellite record,
- 1.082 million km2 (4.2%)  below the 2010's average,
- 0.699 million km2 (2.8%)  below 2017,
- 0.911 million km2 (3.9%)  above 2016 (the record year),

In recent days average Antarctic extent loss was insufficient to offset very high Arctic extent gain.

There are on average just 8 days to the maximum, with 96% of the season's extent gain done.
The likelihood from past years is a still a 2nd lowest maximum about 400k less than 2017 (2nd lowest) and 1 million km2 above 2016 (lowest).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 04, 2018, 07:53:55 AM
Global Sea Ice Extent as 3rd November  24,965,626  km2

This is
- second lowest in the satellite record,
- 0.772 million km2 (3.0%)  below the 2010's average,
- 0.120 million km2 (0.5%)  below 2017,
- 1.337 million km2 (5.7%)  above 2016 (the record year),

In the last fortnight or so Antarctic extent loss at average was insufficient to offset very high Arctic extent gain.

There is on average just 1 days to the maximum, with 99.4% of the season's extent gain done.
Higher Arctic extent gain is likely to continue so the maximum may well be delayed. The likelihood from past years is a still a 2nd or 3rd lowest maximum close to 2017 (2nd lowest) and 1.4 million km2 above 2016 (lowest).
Title: Re: Global sea ice area and extent data
Post by: Stephan on November 04, 2018, 08:29:45 AM
So, finally the 2018 curve comes very close to the 2017's curve and leaves 2016 as an exceptionally low year well behind it. I wonder whether the high arctic gains will stop after most of the Central Seas have now been freezing over.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 06, 2018, 11:12:36 AM
Global Sea Ice Extent as 5 November 24,928,742 km2

This is
- second lowest in the satellite record,
- 0.787 million km2 (3.1%)  below the 2010's average,
- 0.113 million km2 (0.5%)  below 2017,
- 1.337 million km2 (5.7%)  above 2016 (the record year),

In the last fortnight or so Antarctic extent loss at average was insufficient to offset very high Arctic extent gain. This changed on this day as arctic sea ice gain was below average and antarctic sea loss was above average. As a result global extent dropped from the current maximum of 25.003 million km2 on November 4th. There is therefore a possibility that Nov 4th was the maximum - which is dead on the average date. However, higher Arctic extent gain may well continue so the maximum may still be delayed. The likelihood from past years is a still a 2nd or 3rd lowest maximum close to 2017 (2nd lowest) and nearly 1.5 million km2 above 2016 on Nov 4th.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 07, 2018, 02:01:21 PM
Global Sea Ice Extent as 6 November  24,794,112 km2

This is
- second lowest in the satellite record,
- 0.909 million km2 (3.5%)  below the 2010's average,
- 0.277 million km2 (1.1%)  below 2017,
- 1.158 million km2 (4.9%)  above 2016 (the record year),

In the last fortnight or so Antarctic extent loss at average was insufficient to offset very high Arctic extent gain. This has changed as arctic sea ice gain is below average and antarctic sea loss is above average. As a result global extent dropped from the current maximum of 25.003 million km2 on November 4th. There is therefore a possibility that Nov 4th was the maximum - which is dead on the average date. However, higher Arctic extent gain may continue so the maximum may still be delayed. The likelihood from past years is a still a 2nd or 3rd lowest maximum close to 2017 (2nd lowest) and around 1.5 million km2 above 2016 on Nov 4th.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 08, 2018, 11:37:15 AM
Global Sea Ice Extent as 7 November   24,706,453 km2

This is
- second lowest in the satellite record,
- 0.978 million km2 (3.8%)  below the 2010's average,
- 0.400 million km2 (1.6%)  below 2017,
- 1.093 million km2 (4.6%)  above 2016 (the record year),

In the last fortnight or so Antarctic extent loss at average was insufficient to offset very high Arctic extent gain. This has changed as arctic sea ice gain is below average and antarctic sea loss is above average. As a result global extent dropped by 300k from the current maximum of 25.003 million km2 on November 4th.

Therefore I assume that Nov 4th was the maximum - which is dead on the average date. However, higher Arctic extent gain may continue so the maximum could still be delayed.
A maximum of 25.003 million is 2nd lowest, 1.24 million above the 2016 record low max, and 0.15 million less than 2017, now 3rd lowest.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 13, 2018, 11:12:58 AM
Global Sea Ice Extent as 12 November 24,681,640 km2

This is
- second lowest in the satellite record,
- 0.754 million km2 (3.0%)  below the 2010's average,
- 0.007 million km2 (0.0%)  below 2017,
- 1.567 million km2 (6.8%)  above 2016 (the record year),

In the last fortnight or so Antarctic extent loss at average or below was insufficient to offset very high Arctic extent gain. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year
Title: Re: Global sea ice area and extent data
Post by: Tor Bejnar on November 13, 2018, 05:19:12 PM
Thank you, gerontocrat, for this: 
Quote
... I have added 2016 and 2017 to one of the graphs to show the contrast with the current year ...
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on November 25, 2018, 09:17:34 AM
Global Sea Ice Extent as 24 November  24,335,046 km2

This is
- third lowest in the satellite record,
- 0.298 million km2 (1.2%)  below the 2010's average,
- 0.926 million km2 (4.0%)  above 2017,
- 2.641 million km2 (12.2%) above 2016 (the record year),

In the last fortnight or so Antarctic extent loss has been at average or below while Arctic extent gain has been well above average. 2018 global extent is now very much with the 2010's average rather than the record low years of 2016 and 2017. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year.
Title: Re: Global sea ice area and extent data
Post by: Neven on November 25, 2018, 06:33:56 PM
So, judging by Wipneus' global sea ice graphs (https://sites.google.com/site/arctischepinguin/home/global-sea-ice), is it safe to saw we've witnessed the second lowest maximum on record, for both extent and area?
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on November 25, 2018, 07:19:33 PM
Looks like some might complain about extent being statistically ignisificantly lower but yea, second lowest it is. Not much of an ice age coming up.
Title: Re: Global sea ice area and extent data
Post by: litesong on November 26, 2018, 04:57:25 PM
extent......second lowest......Not much of an ice age coming up.
Average Arctic sea ice VOLUME for November 1, for the period 1980-89, was ~18,100 cubic kilometers. November 1, 2018 sea ice VOLUME is ~7200 cubic kilometers, ~10,900 cubic kilometers less than the 1980-89 period for November. Energy needed to melt 10,900 cubic kilometers of ice is ~ 34 times the U.S. consumption of energy.
Yes, before AGW deniers talk "ice age" (& not even then), the Arctic sea ice of the 1980's must be restored.
Title: Re: Global sea ice area and extent data
Post by: Feeltheburn on November 27, 2018, 05:39:34 AM
So, judging by Wipneus' global sea ice graphs (https://sites.google.com/site/arctischepinguin/home/global-sea-ice), is it safe to saw we've witnessed the second lowest maximum on record, for both extent and area?

The graphs also show that with Antarctic sea ice melt slowing down and arctic ice higher now than many previous years, 2018 has moved up to third lowest after 2016 (lowest) and 2017 (second lowest. In addition, the current low negative slope of the 2018 line shows a trajectory that might put it back into the pack, with a total sea ice level not particularly low compared to prior years.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 01, 2018, 10:14:18 AM
JAXA Global Sea Ice Extent as 30 November   23,704,663 km2

This is
- third lowest in the satellite record,
- 0.504 million km2 (2.1%)  below the 2010's average,
- 0.660 million km2 (2.9%)  above 2017, (the 2nd lowest year)
- 2.334 million km2 (10.9%) above 2016 (the record year),

In the last week or so Antarctic extent loss has been at average or just below while Arctic extent gain has been well below average. This has resulted in above average extent loss in the week. 2018 global extent is a bit closer to the record low years of 2016 and 2017. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year.

The February minimum is, on average, 77 days away, with only 17% of extent loss from maximum done. It is all in the lap of the ice gods, e.g. the goddess of winter, death and rivers, Morana.

Quote
She is a Slavic goddess and the only one that connects Nav (Slavic version of Hell) to Earth and Nebo (Slavic version of Heaven). When talking about her one must remember that despite being gruesome and sometimes clearly evil, she is the mother goddess of all Slavic people.

Appearance: She is both a young, beautiful virgin and terrifying crone. She has deathly pale face, but it's usually covered with black ash since she enters the houses through chimneys to kill people (talk about Grim Santa). Her hands are very similar to wolf's paws and she has big talons. All that is accompanied by her gruesome fangs and huge, terrible eyes. She is said to have extraordinary long hair with which she drags the souls to the netherworld.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 07, 2018, 06:43:56 PM
Global extent starting to look interesting. A proper look in a few days, methinks. meanwhile, a graph.
Title: Re: Global sea ice area and extent data
Post by: Ktb on December 09, 2018, 08:32:45 AM
Wipneus shows global extent remains in 3rd, while global area moved into 2nd lowest.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 11, 2018, 12:01:29 PM
Antarctic Sea ice extent and area falling off a cliff. Two graphs using JAXA extent data attached.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 12, 2018, 09:41:58 AM
Antarctic Sea ice extent and area falling off a cliff, overwhelms above average Arctic extent gain.
Two graphs using JAXA extent data attached.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 14, 2018, 12:02:42 PM
The graphs again.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 15, 2018, 09:23:30 AM
JAXA Global Sea Ice Extent as 14 December 21,267,980 km2

This is
- third lowest in the satellite record,
- 1.201 million km2 (5.3%)  below the 2010's average,
- 0.087 million km2 (0.5%)  above 2017, (the 2nd lowest year)
- 1.979 million km2 (10.3%) above 2016 (the record year),

In the last 2 weeks or so Antarctic extent loss has been mostly above average while Arctic extent gain has been mixed. This has resulted in above average extent loss in this period. Since maximum, extent loss has been 0.6 million km2 (19 %) greater than the last 10 years average

2018 global extent is a bit much closer to 2017, but still a long way above the record low year of 2016. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year.

The February minimum is, on average, 63 days away, with 35% of extent loss from maximum done. Average extent loss from now to minimum would result in a record low minimum, but at this early in the season it is all in the lap of the ice gods. (See the Holocene Extinction thread for various choices).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 17, 2018, 03:32:39 PM
With JAXA having problems, here is some NSIDC stuff
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 18, 2018, 11:35:16 AM
Here are a couple of graphs on JAXA Global Sea Ice Extent. The odd data from the Arctic makes the graphs look odd.
Title: Re: Global sea ice area and extent data
Post by: magnamentis on December 18, 2018, 11:10:49 PM
damn hudson wouldn't freeze over LOL i thought i was a bit unfair by saying it will survive prediction by a months but now it's way beyond a month.

anyhow, relieve (cold front) is coming soon to put an end to it ;)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 21, 2018, 10:19:12 AM
JAXA Global Sea Ice Extent as 20 December  19,608,366 km2

This is
- 2nd lowest in the satellite record,
- 1.830 million km2 (8.5%)  below the 2010's average,
- 0.501 million km2 (2.5%)  below 2017, (the 2nd lowest year)
- 1.011 million km2 (5.4%) above 2016 (the record year),

In the last 2 weeks or so Antarctic extent loss has been mostly very much above average while Arctic extent gain has been mixed. This has resulted in above average extent loss in this period. Since maximum, extent loss has been 1.3 million km2 (31 %) greater than the last 10 years average

2018 global extent is significantly lower than 2017, and rapidly closing on the record low year of 2016. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year.

The February minimum is, on average, 57 days away, with 46% of extent loss from maximum done. Average extent loss from now to minimum would result in a record low minimum, but at this early in the season it is all in the lap of the ice gods. (See the Holocene Extinction thread for various choices of many available gods).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 22, 2018, 10:52:59 AM
JAXA Global Sea Ice Extent as at 21 December 19,353,647  km2

This is
- 2nd lowest in the satellite record,
- 1.899 million km2 (8.9%)  below the 2010's average,
- 0.483 million km2 (2.4%)  below 2017, (the 2nd lowest year)
- 0.854 million km2 (4.6%) above 2016 (the record year), getting closer every day

In the last 2 weeks or so Antarctic extent loss has been mostly very much above average while Arctic extent gain has been mixed. This has resulted in above average extent loss in this period. Since maximum, extent loss has been 1.39 million km2 (33 %) greater than the last 10 years average

2018 global extent is significantly lower than 2017, and rapidly closing on the record low year of 2016. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year.

The February minimum is, on average, 56 days away, with 47.5% of extent loss from maximum done. Average extent loss from now to minimum would result in a record low minimum of 14.65 million km2, some 0.9 million km2 below the previous record low. This is unlikely, as it would require Antarctic sea ice extent to approach a low extent of about half of the previous record low.  At this early in the season it is all in the lap of the ice gods.
Title: Re: Global sea ice area and extent data
Post by: oren on December 22, 2018, 12:40:40 PM
Quote
- 0.853 million km2 (2.4%)  below 2017, (the 2nd lowest year)
- 0.011 million km2 (4.6%) above2016 (the record year)
The solstice hangover interfered.
0.462 below 2017, 0.853 above 2016, if I am not mistaken.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 22, 2018, 01:13:07 PM
Quote
- 0.853 million km2 (2.4%)  below 2017, (the 2nd lowest year)
- 0.011 million km2 (4.6%) above2016 (the record year)
The solstice hangover interfered.
0.462 below 2017, 0.853 above 2016, if I am not mistaken.
"Whoops", he croaked.
Title: Re: Global sea ice area and extent data
Post by: Ktb on December 27, 2018, 09:17:01 AM
2018 extent is now a mere 350k (JAXA) above 2016. I sense a new record holder in the next 2-5 days. Especially with 2016's flatline from now through the first few days of the new year.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 27, 2018, 03:51:02 PM
2018 extent is now a mere 350k (JAXA) above 2016. I sense a new record holder in the next 2-5 days. Especially with 2016's flatline from now through the first few days of the new year.
NSIDC data suggests pretty much the same thing.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 28, 2018, 12:21:37 PM
JAXA Global Sea Ice Extent as at 27 December  17,911,717  km2

This is
- 2nd lowest in the satellite record,
- 2.304 million km2 (11.4%)  below the 2010's average,
- 0.986 million km2 (5.2%)  below 2017, (the 2nd lowest year)
- 0.148 million km2 (0.8%) above 2016 (the record year), getting closer every day

In the last 2 weeks or so Antarctic extent loss has been very much above average while Arctic extent gain has been mixed. This has resulted in above average extent loss in this period. Since maximum, extent loss has been 1.80 million km2 (34 %) greater than the last 10 years average

2018 global extent is significantly lower than 2017, and rapidly closing on the record low year of 2016. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year.

On average, in the last 4 days of the year (2010's) extent drops by 550k.
In 2016,  in the last 4 days of the year extent dropped by just 110k.
Therefore it is probable that on Dec 31 2018 global extent will be the lowest for that day in the satellite record (and maybe for several millenia?)

The February minimum is, on average, 50 days away, with 59% of extent loss from maximum done. Average extent loss from now to minimum would result in a record low minimum of 14.24 million km2, some 1.3 million km2 below the previous record low. This is unlikely, as it would require Antarctic sea ice extent to approach a low extent of about half of the previous record low. At this early in the season it is all in the lap of the ice gods, but a record low minimum gets more likely day by day.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 28, 2018, 02:17:13 PM
2018 extent is now a mere 350k (JAXA) above 2016. I sense a new record holder in the next 2-5 days. Especially with 2016's flatline from now through the first few days of the new year.
NSIDC Daily Sea Ice Extent data has 2018 at a record low already.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 29, 2018, 10:55:41 AM
JAXA Global Sea Ice Extent as at 28 December 17,780,377  km2

This is
- 2nd lowest in the satellite record,
- 2.307 million km2 (11.5%)  below the 2010's average,
- 0.916 million km2 (4.9%)  below 2017, (the 2nd lowest year)
- 0.011 million km2 (0.1%) above 2016 (the record year), getting closer every day

In the last 2 weeks or so Antarctic extent loss has been very much above average while Arctic extent gain has been mixed. This has resulted in above average extent loss in this period. A change may be in progress. Since maximum, extent loss has been 1.81 million km2 (33 %) greater than the last 10 years average

2018 global extent is significantly lower than 2017, and rapidly closing on the record low year of 2016. I have added 2016 and 2017 to one of the graphs to show the contrast with the current year.

On average, in the last 3 days of the year (2010's) extent drops by 420k.
In 2016,  in the last 3 days of the year extent dropped by just 116k.
Therefore it is probable that on Dec 31 2018 global extent will be the lowest for that day in the satellite record (and maybe for several millenia?)

The February minimum is, on average, 49 days away, with 60% of extent loss from maximum done. Average extent loss from now to minimum would result in a record low minimum of 14.25 million km2, some 1.3 million km2 below the previous record low. This is unlikely, as it would require Antarctic sea ice extent to approach a low extent of about half of the previous record low. At this early in the season it is all in the lap of the ice gods, but a record low minimum gets more likely day by day.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 30, 2018, 10:41:33 AM
JAXA Global Sea Ice Extent as at 29 December  17,724,671   km2

This is
- the lowest in the satellite record,
- 2.242 million km2 (11.2%)  below the 2010's average,
- 0.847 million km2 (4.6%)  below 2017, (the 2nd lowest year)
- 0.114 million km2 (0.6%) below 2016 (the record year).

In the last 2 weeks or so Antarctic extent loss has been very much above average while Arctic extent gain has been mixed. This has resulted in above average extent loss in this period. A change is probably in progress as Antarctic sea ice loss slows as high concentration coastal ice now predominates. Since maximum, extent loss has been 1.72 million km2 (31 %) greater than the last 10 years average, and from now is likely to reduce. However, the probability for a new record low minimum remains, though not by over a million km2 as currently indicated in the table.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on December 31, 2018, 11:37:05 AM
JAXA Global Sea Ice Extent as at 30 December 17,670,704 km2

Still lowest by 102 k
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 01, 2019, 04:15:07 PM
JAXA Global Sea Ice Extent as at 30 December  17,318,948 km2

Still lowest by 335 k
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 05, 2019, 02:02:48 PM
JAXA Global Sea Ice Extent as at 30 December  17,318,948 km2

The recent gradual reduction in daily Antarctic sea ice loss combined with the recent change to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 2nd lowest.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 06, 2019, 10:53:52 AM
JAXA Global Sea Ice Extent as at 5 January 2019 17,369,115 km2

The recent gradual reduction in daily Antarctic sea ice loss combined with the recent change to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 2nd lowest on the 4th Jan, and back to 1st lowest on the 5th by just 23k km2.
Title: Re: Global sea ice area and extent data
Post by: Juan C. García on January 09, 2019, 02:58:05 PM
[ADS NIPR VISHOP (JAXA)] Global Sea Ice Extent.

January 8th, 2019:
     17,056,375 km2, a drop of -137,992 km2.
     2019 is the lowest on record.


We miss you Gerontocrat. Hope everything is fine!  ;)
Title: Re: Global sea ice area and extent data
Post by: b_lumenkraft on January 09, 2019, 03:00:26 PM
Quote
We miss you Gerontocrat. Hope everything is fine!

+1
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 09, 2019, 04:48:54 PM
[ADS NIPR VISHOP (JAXA)] Global Sea Ice Extent.

January 8th, 2019:
     17,056,375 km2, a drop of -137,992 km2.
     2019 is the lowest on record.


We miss you Gerontocrat. Hope everything is fine!  ;)
Hi, Juan.

Computer & Mobile phone died.
Sticking plaster and soothing words applied.
Data rescue underway. (Amazingly, back-up system seems to have worked).

With luck back in action tomorrow.

What to do when this clapped out old laptop finally dies is a question I am avoiding.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 10, 2019, 06:22:50 AM
JAXA Global Sea Ice Extent as at 9 January 2019  17,027,437 km2

The continuing gradual reduction in daily Antarctic sea ice loss combined average to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 2nd lowest on the 4th Jan, and back to 1st lowest on the 5th by just 87k km2.

On average 37 days to minimum, with 78% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 15 million km2, some 0.5 million km2 below the previous record low. BUT looking at the results from the previous 2 years, a more likely scenario, suggests a definite very low result, and maybe a 50-50 chance of a record low.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 10, 2019, 07:23:03 AM
The attached graphs show how the rate of extent loss is associated with sea ice concentration (i.e. ratio of area to extent), and also the rate of change in Albedo Warming Potential.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 12, 2019, 10:35:00 AM
JAXA Global Sea Ice Extent as at 11 January 2019  17,027,437 km2

The continuing gradual reduction in daily Antarctic sea ice loss combined with mostly average to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 2nd lowest by 187k km2 (compared with 2017).

On average 35 days to minimum, with 80% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 15 million km2, some 0.5 million km2 below the previous record low. BUT looking at the results from the previous 2 years, a more likely scenario, suggests a definitely very low result, and maybe a 50-50 chance of a record low.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 20, 2019, 04:45:40 PM
JAXA Global Sea Ice Extent as at 19 January 2019  17,027,437 km2

The continuing reduction in daily Antarctic sea ice loss combined with mostly average to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 4th lowest, extent above 2018, 2017 and 2011.

On average 27 days to minimum, with 88.7% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 15.6 million km2, close to the previous record low.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on January 25, 2019, 11:17:55 AM
JAXA Global Sea Ice Extent as at 24 January 2019   16,522,965  km2

The continuing reduction in daily Antarctic sea ice loss combined with mostly average to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 5th lowest, extent above 2018, 2017, 2006 and 2011.

On average 22 days to minimum, with 92.2% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 15.82 million km2, 270k above the previous record low of 2018.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 01, 2019, 12:38:03 PM
JAXA Global Sea Ice Extent as at 31 January 2019 16,398,255  km2

The continuing reduction in daily Antarctic sea ice loss combined with mostly average to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 4th lowest, extent above 2018, 2017, and 2006 .

On average 15 days to minimum (On Valentine's day), with 95.7% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 16.01 million km2, 450k above the previous record low of 2018.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 02, 2019, 01:44:46 PM
JAXA Global Sea Ice Extent as at 1 February 2019  16,332,280  km2

The continuing reduction in daily Antarctic sea ice loss combined with mostly average to above average Arctic sea ice gain has resulted in Global Sea Ice Extent becoming 4th lowest, extent above 2018, 2017, and 2006. However, in the last 2 days Arctic has lost ice extent, reversing this trend somewhat.

On average 14 days to minimum (On Valentine's day), with 95.9% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 15.96 million km2, 408k above the previous record low of 2018.

This last 14 days may well produce another surprise or two.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 05, 2019, 08:35:28 AM
JAXA Global Sea Ice Extent as at 4 February 2019   16,268,817   km2

Global Sea Ice Extent is 3rd lowest, above 2018 and 2017. In the last week Arctic Sea Ice has lost extent, while Antarctic Sea Ice Extent daily loss remained below average.

On average 10 days to minimum (On Valentine's day), with 96.8% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 15.98 million km2, 425k above the previous record low of 2018.

This remaining 10 days or so could still produce another surprise or two.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 11, 2019, 05:56:08 AM
JAXA Global Sea Ice Extent as at 10 February 2019  16,394,681 km2

Global Sea Ice Extent is 5th lowest, above 2018, 2017, 2010 and 2006. In the last week Arctic Sea Ice gain has tended to above average, while Antarctic Sea Ice Extent daily loss remained below average.

On average 4 days to minimum (On Valentine's day), with 98.5% of extent loss done, with an outcome from average remaining extent loss of a possible minimum of around 16.26 million km2, 711k above the previous record low of 2018.
Title: Re: Global sea ice area and extent data
Post by: Wipneus on February 11, 2019, 04:16:37 PM
Following the GIOMAS update (https://forum.arctic-sea-ice.net/index.php/topic,1840.msg188716/topicseen.html#msg188716) here are the update volume and volume-anomaly graphs.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 13, 2019, 12:30:07 PM
JAXA Global Sea Ice Extent as at 12 February 2019   16,403,991  km2

Global Sea Ice Extent is 6th lowest, above 2018, 2017, 2016, 2010 and 2006. In the last week Arctic Sea Ice gain has tended to above average, while Antarctic Sea Ice Extent daily loss remained below average apart from the last 2 days.

On average 2 days to minimum (On Valentine's day), with 99.2% of extent loss done, with an outcome from average remaining extent loss of 16.33 million km2. However, the current minimum is 16.25 million km2 on the 5th February. Unless there is a surprise, this will be the minimum for 2019. This makes the table of projections AA1 attached basically meaningless, which (IMHO) happens to all projections at and around the times of minima and maxima.


Title: Re: Global sea ice area and extent data
Post by: Stephan on February 14, 2019, 07:34:58 PM
If the global minimum already has occurred it will be the earliest minimum (Feb 05) in the last 15 years. However, some days or even two weeks back and forth does not mean anything...
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 15, 2019, 08:32:54 AM
JAXA Global Sea Ice Extent as at 14 February 2019  16,542,286 km2

Global Sea Ice Extent on this day is 6th lowest, above 2018, 2017, 2016, 2010 and 2006. In the last week Arctic Sea Ice gain has tended to above average, while Antarctic Sea Ice Extent daily loss remained below average apart from the last 2 days.

On average 0 days to minimum. However, the current minimum is  16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was third lowest in the satellite record since 1979. (See table AA3 attached).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 17, 2019, 04:40:55 PM
JAXA Global Sea Ice Extent as at 16 February 2019   16,485,367 km2

Global Sea Ice Extent on this day is 6th lowest, above 2018, 2017, 2016, 2010 and 2006.

On average 2 days after the minimum. Modest reduction in sea ice extent in the last 2 days. The current minimum is 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was third lowest in the satellite record since 1979.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 23, 2019, 11:42:02 AM
JAXA Global Sea Ice Extent as at 22 February 2019 :-  16,659,330  km2

Global Sea Ice Extent on this day is 6th lowest, above 2018, 2017, 2016, 2010 and 2006.

The minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 24, 2019, 01:49:42 PM
JAXA Global Sea Ice Extent as at 23 February 2019 :-   16,598,381  km2

A surprise today - ice extent losses in both hemispheres means 23 Feb global ice extent LOSS was 61K, 106 K LESS than the average GAIN of 45 k on this day.

Global Sea Ice Extent on this day is 6th lowest, above 2018, 2017, 2016, 2010 and 2006.

The minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 25, 2019, 10:25:42 AM
JAXA Global Sea Ice Extent as at 24 February 2019 :-  16,499,734  km2

A surprise for a second day - ice extent losses in both hemispheres means 24 Feb global ice extent LOSS was 99K, 144 K LESS than the average GAIN of 45 k on this day.

Global Sea Ice Extent on this day is 5th lowest, above 2018, 2017, 2011 and 2006.

The minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 26, 2019, 07:24:26 AM
JAXA Global Sea Ice Extent as at 24 February 2019 :- 16,460,942  km2

A surprise for a third day - large ice extent losses in the Arctic + modest increase in the Antarctic means 24 Feb global ice extent LOSS was 39K, 81 K LESS than the average GAIN of 42 k on this day.

Global Sea Ice Extent on this day is 5th lowest, above 2018, 2017, 2011 and 2006.

The minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 27, 2019, 09:58:51 AM
JAXA Global Sea Ice Extent as at 26 February 2019 :-  16,464,387  km2

Global Sea Ice Extent on this day is 5th lowest, above 2018, 2017, 2011 and 2006.

The minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979.
Title: Re: Global sea ice area and extent data
Post by: Dharma Rupa on February 27, 2019, 03:22:19 PM
When that hunk of ice breaks off in Antarctica does the sea ice suddenly jump by two New Yorks?
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 27, 2019, 03:52:58 PM
When that hunk of ice breaks off in Antarctica does the sea ice suddenly jump by two New Yorks?
The Larsen C A68A berg had an area of 5,800 km2, a bit less now. This is HUGE to small animals like ourselves and TINY in the context of Antarctic Sea ice which is in the range of 2,500,000 to 18,000,000 km2.  Bergs once separated from its ice shelf or glacier I presume become part of measured sea ice extent and area. - once the mask is altered to the new ice shelf edge.

Someone on this forum who actually knows about this stuff may clarify. If no response, suggest you chuck your question onto the "stupid questions" thread.
Title: Re: Global sea ice area and extent data
Post by: Klondike Kat on February 27, 2019, 04:22:32 PM
When that hunk of ice breaks off in Antarctica does the sea ice suddenly jump by two New Yorks?
The Larsen C A68A berg had an area of 5,800 km2, a bit less now. This is HUGE to small animals like ourselves and TINY in the context of Antarctic Sea ice which is in the range of 2,500,000 to 18,000,000 km2.  Bergs once separated from its ice shelf or glacier I presume become part of measured sea ice extent and area. - once the mask is altered to the new ice shelf edge.

Someone on this forum who actually knows about this stuff may clarify. If no response, suggest you chuck your question onto the "stupid questions" thread.

It all depends on from where the ice originated.  Since the sea ice expands and contracts from the ice shelf, differentiating sea ice from shelf ice is somewhat nebulous, and open to the particular masking.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on February 28, 2019, 07:39:10 AM
JAXA Global Sea Ice Extent as at 27 February 2019 :-   16,436,229 km2

Global Sea Ice Extent on this day is 5th lowest, above 2018, 2017, 2011 and 2006.

The minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 01, 2019, 10:46:50 AM
JAXA Global Sea Ice Extent as at 28 February 2019 :- 16,397,476 km2

Global Sea Ice Extent on this day is 5th lowest, above 2018 & 2017.

The minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 02, 2019, 10:31:54 AM
JAXA Global Sea Ice Extent as at 1 March 2019 :- 16,397,476 km2

Global Sea Ice Extent on this day is 3rd lowest, above 2018 & 2017.

The current minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979. Assuming that this is the case...
- extent gain on this day 8k, 68k less than average gain of 76 k,
- extent gain from minimum to date is 160k, 390 k (72%) less than the average gain of 550k,
- last 10 years average remaining extent gain would give a maximum of 24.75 million km2,  986k more than the record low max in 2016.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 03, 2019, 12:57:35 PM
JAXA Global Sea Ice Extent as at 2 March 2019 :-  16,516,698 km2

Global Sea Ice Extent on this day is 4th lowest, above 2018 & 2017 & 2016.

The current minimum for 2019 was 16,249,255 km2 that occurred on the 5th February. Unless there is a very big surprise, this will be the minimum for 2019, and was SIXTH lowest in the satellite record since 1979. Assuming that this is the case...
- extent gain on this day 111k, 68k greater than the average gain of 43 k on this day,
- extent gain from minimum to date is 270k, 330 k (55%) less than the average gain of 600k,
-on average 6.5 of extent gain done and 247 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.69 million km2,  925k more than the record low max of 2016.

From now on weekly updates only unless a big surprise (either way).

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 09, 2019, 10:35:44 AM
JAXA Global Sea Ice Extent as at 8 March 2019 :-   16,786,936  km2

Global Sea Ice Extent on this day is 3rd lowest, above 2018 & 2017.

- extent gain on this day 51k, 1k less than the average gain of 52 k on this day,
- extent gain from minimum to date is 540k, 430 k (45%) less than the average gain of 970k,
-on average 10.7% of extent gain done and 241 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.54 million km2,  908k more than the record low max of 2016.

From now on only occasional updates unless a big surprise (either way).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 15, 2019, 10:53:13 AM
JAXA Global Sea Ice Extent as at 14 March 2019 :-    17,146,871  km2

Global Sea Ice Extent on this day is 3rd lowest, above 2017 & 2006.

- extent gain on this day 4k, 83k less than the average gain of 87 k on this day,
- extent gain from minimum to date is 900k, 550k (38%) less than the average gain of 1,450k,
-on average 15.9% of extent gain done and 235 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.87 million km2,  1,237 k more than the record low max of 2016.

From now on only occasional updates unless a big surprise (either way).
[/quote]
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 16, 2019, 09:25:02 AM
JAXA Global Sea Ice Extent as at 15 March 2019 :-    17,146,871  km2

Global Sea Ice Extent on this day is 3rd lowest, above 2017 & 2006. Unusual extent loss on this day.

- extent loss on this day 19k, 108k less than the average gain of 89 k on this day,
- extent gain from minimum to date is 880k, 650k (43%) less than the average gain of 1,530k,
-on average 16.9% of extent gain done and 234 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.84 million km2,  1,208 k more than the record low max of 2016.
__________________________________________________________
From now on only occasional updates unless unusual stuff going on.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 17, 2019, 12:52:51 PM
JAXA Global Sea Ice Extent as at 16 March 2019 :-  17,112,765  km2

Global Sea Ice Extent on this day is 3rd lowest, above 2017 & 2006. Unusual extent loss for a second day.

- extent loss on this day 15k, 94k less than the average gain of 79 k on this day,
- extent gain from minimum to date is 860k, 750k (46%) less than the average gain of 1,610k,
-on average 17.8% of extent gain done and 233 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.84 million km2,  1,205 k more than the record low max of 2016.
__________________________________________________________
From now on only occasional updates unless unusual stuff going on.
[/quote]
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 23, 2019, 09:58:01 AM
JAXA Global Sea Ice Extent as at 22 March 2019 :-   17,426,312  km2

Global Sea Ice Extent on this day is 3rd lowest, above 2017 & 2006. Unusual extent loss for a second day. Extent gains a mixture of below or above average in the last few days.

- extent gain on this day 13k, 45k less than the average gain of 58 k on this day,
- extent gain from minimum to date is 1,180k, 790k (40%) less than the average gain of 1,790k,
-on average 21.8% of extent gain done and 227 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.82 million km2,  1,179 k more than the record low max of 2016.
__________________________________________________________
From now on only occasional updates unless unusual stuff going on.
Title: Re: Global sea ice area and extent data
Post by: Rodius on March 23, 2019, 10:31:57 AM
I want to predict that on April 26 it will be on 19,500,000
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 23, 2019, 11:37:48 AM
I want to predict that on April 26 it will be on 19,500,000
Using the Artificial Moron embedded in my computer, I added  linear and x2 trend lines.
As you can see, probably of zero value.

My own experience of my own forecasts is that my only hope is that there is a possibility, no matter how close to zero, that the impossible can happen (pace Douglas Adams).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 24, 2019, 11:18:26 AM
A large drop in Arctic Extent makes an unusual Global area ice extent drop on the 23rd March.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 25, 2019, 01:10:04 PM
JAXA Global Sea Ice Extent as at 24 March 2019 :-    17,392,354  km2

Global Sea Ice Extent on this day is 3rd lowest, above 2017 & 2006. Unusual extent loss for a second day - low Antarctic gain + high Arctic loss.

- extent loss on this day 16k, 85k less than the average gain of 69 k on this day,
- extent gain from minimum to date is 1,480k, 970k (46%) less than the average gain of 2,110k,
-on average 23.4% of extent gain done and 225 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.31** million km2,  671k more than the record low max of 2016 and 2nd lowest in the satellite record.

(N.B. 24.31** is a corrected calculation - I screwed up and exaggerated the projected maximum)
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe that is the new normal.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 30, 2019, 11:18:26 AM
JAXA Global Sea Ice Extent as at 29 March 2019 :-    17,392,354  km2

Global Sea Ice Extent on this day is 2nd lowest, above 2017. Unusual extent loss on this day - low Antarctic gain + high Arctic loss continue.

- extent loss on this day 45k, 99k less than the average gain of 54 k on this day,
- extent gain from minimum to date is 1,290k, 1,230k (49%) less than the average gain of 2,510k,
-on average 27.8% of extent gain done and 220 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 24.05 million km2,  411k more than the record low max of 2016 and 2nd lowest in the satellite record.

____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on March 31, 2019, 11:08:50 AM
JAXA Global Sea Ice Extent as at 30 March 2019 :- 17,434,339  km2

Global Sea Ice Extent on this day is 2nd lowest, above 2017. A second and even greater unusual extent loss on this day - low Antarctic gain + high Arctic loss continue.

- extent loss on this day 100k,  a variation of 171k from the the average gain of 71 k on this day,
- extent gain from minimum to date is 1,190k, 1,400k (54%) less than the average gain of 2,580k,
-on average 28.6% of extent gain done and 219 days to maximum ( 4-Nov),
- last 10 years average remaining extent gain would give a maximum of 23.88 million km2,  240k more than the record low max of 2016 and 2nd lowest in the satellite record.

____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
Title: Re: Global sea ice area and extent data
Post by: Rodius on March 31, 2019, 02:51:48 PM
And now the Artificial Moron embedded in your computer agrees with 19,500,000 on the 26th April.
All that needs to happen is for both poles to start behaving in an average manner to be correct.

Given the heat in the Arctic, I think my rather silly bet that I never expected to have a show in being right may actually be too high.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 03, 2019, 09:31:03 AM
JAXA Global Sea Ice Extent as at 2 April 2019 :- 17,519,837  km2

Global Sea Ice Extent on this day is 2nd lowest, above 2017. Slightly below Antarctic gain + high Arctic loss continues.

- extent gain on this day 15k,  a variation of 49k from the the average gain of 64 k on this day,
- extent gain from minimum to date is 1,270k, 1,540k (55%) less than the average gain of 2,810k,
-on average 31.1% of extent gain done and 216 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.74 million km2,  100k more than the record low max of 2016 and 2nd lowest in the satellite record. In the next 2 days 2017 extent gains were very high, so there is a good chance that 2019 will be lowest in the satellite record tomorrow or the day after.

Also note what has happened to the x2 projection line. Just 3 days of below average gain shifts the 19.5 million extent as forecasted by Rodius for the 26th April to the 14th May. That very short-term fprecasts can be so wobbly suggests that forecasts this early in the season for the final result need taking with not a pinch but a bucketful of salt.

____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
[/quote]
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 04, 2019, 08:29:07 AM
JAXA Global Sea Ice Extent as at 3 April 2019 :-  17,577,832 km2

Global Sea Ice Extent on this day is 2nd lowest, above 2017.Average Antarctic gain + average Arctic loss on this day.

- extent gain on this day 58k,  5k less than the the average gain of 63 k on this day,
- extent gain from minimum to date is 1,330k, 1,540k (54%) less than the average gain of 2,870k,
-on average 31.8% of extent gain done and 215 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.73 million km2,  95k more than the record low max of 2016 and 2nd lowest in the satellite record. Tomorrow 2017 extent gain were very high, so there is a good chance that then 2019 will be lowest in the satellite record, even if only for one day.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
Title: Re: Global sea ice area and extent data
Post by: oren on April 04, 2019, 02:23:29 PM
In 6 weeks it went from 0.4M to 2M km2 below the 2010s average. System volatility is certainly increasing.
Title: Re: Global sea ice area and extent data
Post by: Stephan on April 05, 2019, 07:56:22 AM
A smaller increase (as Average) in Antarctic and a larger decrease (as average) in the Arctic today led to a new record low in global sea ice, as "announced" by several people here in this forum. Today it came true.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 05, 2019, 12:58:33 PM
JAXA Global Sea Ice Extent as at 3 April 2019 :-   17,592,526 km2

Continuing Antarctic extent gain at or a bit below average and Arctic extent loss continuing at above average,  has resulted in Global Sea Ice Extent on this day being lowest. Another line being written on a previously unused part of the graph paper.

- extent gain on this day 15k,  42k less than the the average gain of 57 k on this day,
- extent gain from minimum to date is 1,340k, 1,580k (54%) less than the average gain of 2,930k,
-on average 32.4% of extent gain done and 214 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.69 million km2,  53k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 06, 2019, 08:55:43 AM
JAXA Global Sea Ice Extent as at 5 April 2019 :- 17,670,997 km2

Until this day, continuing Antarctic extent gain at or a bit below average and Arctic extent loss continuing at above average,  has resulted in Global Sea Ice Extent on this day being lowest. Another line being written on a previously unused part of the graph paper.

- extent gain on this day 78k,  22k more than the the average gain of 56 k on this day,
- extent gain from minimum to date is 1,420k, 1,560k (52%) less than the average gain of 2,980k,
-on average 33.1% of extent gain done and 213 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.71 million km2,  75k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
Title: Re: Global sea ice area and extent data
Post by: Stephan on April 07, 2019, 08:52:21 AM
I compared the actual JAXA extent value (April 6) of Arctic and Antarctic with the decadal averages of the 10s, 00s, 90s, and 80s and calculated the cumulative difference of 2019 (example: in the Arctic we are 20 days ahead compared to the 10s, in the Antarctic we are 11 days behind the 10s average, which sums up to 31 days, almost a month).
Compared to earlier decades this difference is even bigger:
April 6, 2019 vs. 00s: 42 days
April 6, 2019 vs. 90s: 50 days
April 6, 2019 vs. 80s: 59 days (almost two months)
So there is a big difference as there is less ice to melt in the Arctic this coming melting season (so less energy needed) and more ice to form in the Antarctic this coming freezing season (more freezing energy to be released). In addition you must also take the Albedo effect into account.
Title: Re: Global sea ice area and extent data
Post by: b_lumenkraft on April 07, 2019, 10:15:40 AM
I compared

You are having a way to look at the data in such a unique way, i'm always impressed. Compare on sir!
Title: Re: Global sea ice area and extent data
Post by: magnamentis on April 07, 2019, 01:33:33 PM
I compared the actual JAXA extent value (April 6) of Arctic and Antarctic with the decadal averages of the 10s, 00s, 90s, and 80s and calculated the cumulative difference of 2019 (example: in the Arctic we are 20 days ahead compared to the 10s, in the Antarctic we are 11 days behind the 10s average, which sums up to 31 days, almost a month).
Compared to earlier decades this difference is even bigger:
April 6, 2019 vs. 00s: 42 days
April 6, 2019 vs. 90s: 50 days
April 6, 2019 vs. 80s: 59 days (almost two months)
So there is a big difference as there is less ice to melt in the Arctic this coming melting season (so less energy needed) and more ice to form in the Antarctic this coming freezing season (more freezing energy to be released). In addition you must also take the Albedo effect into account.

a cumulation of time to express energy is interesting, nevertheless and even though i got your point and agree, those days are kind of overlapping (timewise) and hence should not be cumulated and used to express energy needed to melt or freeze.

if at all one could perhaps take an average between SH and NH to express an average of such kind but again, cumulation of those days are a bit abstract and can lead to misinterpretation.

to avoid such misunderstanding i repeat, i understand what you are trying to convey and i agree to your thoughts and often think about that the exact same way.

of course and as always, in case i'm to one who missed a point here, don't hesitate to enlighten me and/or elaborate further, the above just came to my mind while reading.

for the rest what others have said, generally interesting to read your various contributions  :)

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 08, 2019, 12:13:12 PM
JAXA Global Sea Ice Extent as at 7 April 2019 :- 17,820,478 km2

For two brief days (4-5 April) extent was lowest. But then high Antarctic gain outweighed above average Arctic loss, so extent is now 22k above 2017.

- extent gain on this day 90k,  13k more than the the average gain of 78 k on this day,
- extent gain from minimum to date is 1,420k, 1,560k (52%) less than the average gain of 2,980k,
-on average 34.7% of extent gain done and 211 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.71 million km2,  75k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
[/quote]
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 13, 2019, 10:21:26 AM
JAXA Global Sea Ice Extent as at 12 April 2019 :-  18,259,037 km2

In recent days extent gain has been at or a bit above average, so extent is now 125k above 2017.

- extent gain on this day 94k, 17k more than the the average gain of 77 k on this day,
- extent gain from minimum to date is 2.01 million km2, 1.53 million km2 (43%) less than the average gain of 2.54 milllion km2,
-on average 39.2% of extent gain done and 206 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.74 million km2,  108k more than the record low max of 2016 and 2nd lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on. But maybe unusual is the new normal.
Title: Re: Global sea ice area and extent data
Post by: Killian on April 14, 2019, 12:13:03 PM
Re: Historic ASI Extent, Daily Records
(Don't know if this is the best place to post this, so if not, please move.)

I was looking at recent years' new records being in mind of my Aug 2015 prediction of new record ASI lows or near record lows for 2016-17 period (two years follwing an El Nino.) 2016 was the second lowest, as we all know. However, it also had extensive new records in the spring and fall months. since 2015, I've always wondered if these numbers of total record days might have some sort of important or useful data embedded, but have never checked.

Today I was poking around and got curious how often new daily records are set year-on-year. Using JAXA's interactive chart I got a rather startling surprise. Using 1979 as the baseline, every single year has had a least a few daily record lows. Every. Year.

That, to me, is unexpected. I just never thought about it, but see it as making the overall trend more robust than it seems just from the yearly low trend.

How many years set new yearly lows using '79 as the baseline (though it seems likely to have been lower than '78)?

'84 (5 yrs)
'85 (1 yr)
'90 (5 yrs)
'95 (5 yrs)
'99 (4 yrs)
'02 (3 yrs)
'05 (3 yrs)
'07 (2 yrs)
'12 (5 yrs)

Currently six years since the last new low. Interestingly, the shorter periods of new lows was indicative of stability, with relatively small changes giving us new lows with the downward trend. then '07 and '12 changed things a lot, with '12 clearly being really anomalous. Of course, both those last years had the dipole set up blowing ice out Fram Strait.

Short version: We consistently had new ASI summer lows since we started tracking this.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 20, 2019, 07:26:15 AM
JAXA Global Sea Ice Extent as at 19 April 2019 :- 18,620,041  km2

In recent days extent gain more below than above average, so extent is now lowest for the 10th day this year, 135k below 2017.

- extent gain on this day 25k, 38k less than the the average gain of 63 k on this day,
- extent gain from minimum to date is 2.37 million km2, 1.41 million km2 (42%) less than the average gain of 4.09 milllion km2 by this day,
-on average 45.3% of extent gain done and 199 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.56 million km2,  78k less than the record low max of 2016 and lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on.
Title: Re: Global sea ice area and extent data
Post by: Stephan on April 21, 2019, 08:43:18 AM
I compared the actual JAXA extent value (April 20) of Arctic and Antarctic with the decadal averages of the 10s, 00s, 90s, and 80s and calculated the cumulative difference of 2019 (example: in the Arctic we are 14 days ahead compared to the 10s, in the Antarctic we are 11 days behind the 10s average, which sums up to 25 days).
Compared to earlier decades this difference is even bigger:
April 20, 2019 vs. 00s: 35 days
April 20, 2019 vs. 90s: 44 days
April 20, 2019 vs. 80s: 50 days
The big difference means that there is less ice to melt in the Arctic this coming melting season (so less energy needed) and more ice to form in the Antarctic this coming freezing season (more freezing energy to be released). In addition you must also take the Albedo effect into account.
The values are slightly smaller than on April 9 as the slope of the averages increase in May (higher melting rates than in April). But the general trend is unchanged. Climate change is on its way!
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 22, 2019, 08:10:29 AM
JAXA Global Sea Ice Extent as at 21 April 2019 :- 18,620,041  km2

Extent gain continuing below average, so extent is now lowest for the 12th day this year, 289k below 2017.

- extent gain on this day 34k, 47k less than the the average gain of 81 k on this day,
- extent gain from minimum to date is 2.44 million km2, 1.79 million km2 (42%) less than the average gain of 4.24 milllion km2 by this day,
-on average 47.0% of extent gain done and 197 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.48 million km2,  157k less than the record low max of 2016 and lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on.
Title: Re: Global sea ice area and extent data
Post by: GoSouthYoungins on April 26, 2019, 04:10:02 PM
It is very telling that despite the record low global area, nobody posts on this thread for days. Record low is just the standard after the last 4 years and it is only really interesting in November when the record can get huge.
Title: Re: Global sea ice area and extent data
Post by: Stephan on April 26, 2019, 07:46:12 PM
Five out of the eight lowest global sea ice extent values were achieved this decade. So "being low" seems to establish itself as the "new normal" (which is obviously sad).
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on April 27, 2019, 07:08:57 AM
It is very telling that despite the record low global area, nobody posts on this thread for days. Record low is just the standard after the last 4 years and it is only really interesting in November when the record can get huge.

Rather I'd say that as this is a numerical product of two very weakly connected regions it's not as interesring as the Antarctic and Arctix separate ones. Sure there can be a connection between areas but this would take years or decades to notice. Rather unexciting compared to direct weather effects on each pole.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on April 27, 2019, 02:11:33 PM
JAXA Global Sea Ice Extent as at 26 April 2019 :-  19,182,588  km2

Despite extent gain being mostly above average the last 5 days, extent still lowest for the 17th day this year, 12 days in a row, 243k below 2017.

- extent gain on this day 52k, 10k more than the the average gain of 42 k on this day,
- extent gain from minimum to date is 2.93 million km2, 1.58 million km2 (35%) less than the average gain of 4.52 milllion km2 by this day,
-on average 50.1% of extent gain done and 192 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.69 million km2,  52k more than the record low max of 2016 and lowest in the satellite record.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on.
Title: Re: Global sea ice area and extent data
Post by: Rodius on April 27, 2019, 02:29:46 PM
I was 300k too high in my prediction that I believed was low and cheeky simply based on the merging the previous years.

I wonder if there is a physical reason for the trend of the last few years being so close?
Title: Re: Global sea ice area and extent data
Post by: magnamentis on May 02, 2019, 07:35:34 PM
global extent slowly but steadily is digging deeper into uncharted territory and nobody is paying attention, so many days without postings.

i've always advocated the opinion that we should pay way more attention to global developments because ultimately, the bigger the scale (the wider the angle to look at things) the more we can see when the sh.. hits the fan, means we can get a better feel about tipping points and irreversible changes.

heat, depending on currents, air and water, as well as depending on weather, is distributed much differently each year, each season and often short terms.

only a global look at temps and events and directions of development will give us a good feel as to what to expect as trends and speed of changes.

we're almost 10% below 2010 average, hence  global loss rate has vastly accelerated if we consider that we're down around 15% from 1980's average.

global sea ice is kind of a global refrigerator/cold-storage and 10% less ice globally must and will have a significant impact on the climate and since i look at sea-level rise as one of most matter of factual and inevitable effects of "global" warming this should trigger some very strong alarm bells, much stronger than the lack of attention in this thread would suggest.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 02, 2019, 08:34:48 PM
JAXA Global Sea Ice Extent as at 1 May 2019 :-   19,253,124  km2

extent gain being below average the last 5 days, extent lowest for the 22nd day this year, 16 days in a row, 496k below 2017.

- extent gain on this day 19k, 34k less than the the average gain of 53 k on this day,
- extent gain from minimum to date is 3.00 million km2, 1.78 million km2 (37%) less than the average gain of 4.78 milllion km2 by this day,
-on average 53.1% of extent gain done and 187 days to maximum ( 4-Nov),

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.49 million km2,  148k less than the record low maximum in 2016 and lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high.
____________________________________________________________________________
From now on only occasional updates unless unusual stuff going on - or nudged by magnamentis
Title: Re: Global sea ice area and extent data
Post by: Stephan on May 02, 2019, 08:53:08 PM
global extent slowly but steadily is digging deeper into uncharted territory and nobody is paying attention, so many days without postings.

...
I do pay attention:
I use a big whiteboard in my office and actualise the difference of Global Sea Ice Extent versus the average 2000-2009 on a daily basis (today e.g. 2.62 M km²). In addition I list the "top three" years (today 2019 - 2017 - 2018). After several weeks my colleagues started to pay attention and discuss climate change issues (most of them were not familiar at all with the global threat we are facing). Few of my colleagues neglect the facts, most of them are aware of the problems and choose little smart solutions for their daily lives.
I think all of us could do things like that to wake up the colleagues, friends and family members. Noone can save the world by themselves - but if everybody pays a little more attention (stairs vs. lift, bike vs. car, home-grewn vegetables instead of intercontinental import etc etc) the world could be a tiny little bit better  :D
Title: Re: Global sea ice area and extent data
Post by: magnamentis on May 02, 2019, 09:54:19 PM
global extent slowly but steadily is digging deeper into uncharted territory and nobody is paying attention, so many days without postings.

...
I do pay attention:
I use a big whiteboard in my office and actualise the difference of Global Sea Ice Extent versus the average 2000-2009 on a daily basis (today e.g. 2.62 M km²). In addition I list the "top three" years (today 2019 - 2017 - 2018). After several weeks my colleagues started to pay attention and discuss climate change issues (most of them were not familiar at all with the global threat we are facing). Few of my colleagues neglect the facts, most of them are aware of the problems and choose little smart solutions for their daily lives.
I think all of us could do things like that to wake up the colleagues, friends and family members. Noone can save the world by themselves - but if everybody pays a little more attention (stairs vs. lift, bike vs. car, home-grewn vegetables instead of intercontinental import etc etc) the world could be a tiny little bit better  :D

great and all true, i basically am aware that some do pay attention while my post was meant to provoke some more discourse over the matter which worked a little bit as it seems.

kind of knocking a few more sleepers out of the bush LOL
Title: Re: Global sea ice area and extent data
Post by: b_lumenkraft on May 03, 2019, 09:26:35 AM
I think all of us could do things like that to wake up the colleagues, friends and family members.

So here is an anecdote:

My nephews birthday, talk about Greta Thunberg, my mother sais something about Greta doing this 'for the money'.
I'm pointing out the exact same issues for 30 years to her and i asked her when the last time was when she thought make this public and call for strikes is a great business model. Of course, she never thought of it and she did not answer and i bet she never had a second thought about my question.

This beautifully describes why i stopped trying to convince people a long time ago. When people trust some random facebook bots more than their own family members, what is there to do?
Title: Re: Global sea ice area and extent data
Post by: Neven on May 03, 2019, 03:04:36 PM
Has the max been reached?  ;)
Title: Re: Global sea ice area and extent data
Post by: Stephan on May 03, 2019, 04:02:28 PM
hopefully not. If yes we are in catastrophic circumstances.
Title: Re: Global sea ice area and extent data
Post by: Tor Bejnar on May 03, 2019, 04:06:46 PM
If Neven suggests it, it must be true!  ::)
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on May 03, 2019, 05:03:00 PM
If Neven suggests it, it must be true!  ::)
This is an exciting conjecture! The posts on ocean currents spread so widely here I can't follow them all but Neven might! Well see how this goes, has ACC moved again a bit more south??
Title: Re: Global sea ice area and extent data
Post by: oren on May 03, 2019, 05:48:45 PM
Seriously, we are still far from the spring maximum.
Title: Re: Global sea ice area and extent data
Post by: Juan C. García on May 03, 2019, 06:39:06 PM
Seriously, we are still far from the spring maximum.

Neven is joking...
But humanity should take the joke seriously!
Some year will happen.
Title: Re: Global sea ice area and extent data
Post by: FrostKing70 on May 03, 2019, 07:46:01 PM
~6 weeks early would be an alarming data point, not a trend, just a single point!
Title: Re: Global sea ice area and extent data
Post by: etienne on May 03, 2019, 08:56:46 PM
Just for fun from jaxa, arctic only, data of May 2nd
years    average value    diminution   %           min value    difference   %
1980s13.9312.88-1.057.54%
1990s13.440.493.52%13.02-0.423.13%
2000s13.060.382.83%12.79-0.272.07%
2010s12.670.392.99%12.16-0.514.03%
Title: Re: Global sea ice area and extent data
Post by: bbr2314 on May 03, 2019, 10:42:21 PM
Has the max been reached?  ;)
Greta Thunberg: I have Aspergers
ASIF posters responding to Neven's joke: WE ALL HAVE ASPERGERS
Title: Re: Global sea ice area and extent data
Post by: kiwichick16 on May 04, 2019, 01:27:11 AM
DON"T PANIC  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

YET.
Title: Re: Global sea ice area and extent data
Post by: GoSouthYoungins on May 04, 2019, 04:28:33 AM
Don't be a moron. PANIC.
Title: Re: Global sea ice area and extent data
Post by: sark on May 04, 2019, 05:06:21 AM
Don't panic?  The polar cell is acting funny.  Crops aren't getting planted.  The decline in nature is so fast now you can point it out in pictures.  The kids are in the streets because they stand to be destroyed, and nobody else has a clue. 

This was a structurally cold winter in a lot of ways, I think.  And the polar cell is doing tricks.  At 15C.  Like in 2016, like Now.

Title: Re: Global sea ice area and extent data
Post by: kiwichick16 on May 04, 2019, 05:40:41 AM
@  Sark    ...we probably have years of stability yet.......perhaps as many as 12 years....
Title: Re: Global sea ice area and extent data
Post by: dnem on May 04, 2019, 01:46:27 PM
@  Sark    ...we probably have years of stability yet.......perhaps as many as 12 years....

!2 years? Probably? To totally reconfigure modern industrial society? Oh, phew!! Now I feel so much better. Sorry for the snark, but not very comforting. 
Title: Re: Global sea ice area and extent data
Post by: kiwichick16 on May 04, 2019, 05:11:59 PM
@ dnem....it was meant as an ironic comment......the opposite of comforting
Title: Re: Global sea ice area and extent data
Post by: roger white on May 06, 2019, 08:15:21 AM
By the latest chart the decade on decade reduction in sea ice extent globally looks like this:
1980's 22,126,425
1990's 22,131,370
2000's 21,872,152
2010's 21,562,353.

So sea ice extent globally went UP in the 1990's?
The decline certainly looks small to the layman...& what would one expect to be " normal" variations from decade anyway...of this magnitude...?

Title: Re: Global sea ice area and extent data
Post by: oren on May 06, 2019, 10:49:11 AM
The thing is, the Arctic and Antarctic sea ice are very different. The whole global sea ice extent metric does not represent a good physical attribute.
First, the seasonal variability in the Antarctic sea ice is much greater, due to parameters of the Earth's orbit around the sun.
The Antarctic has a continental ice sheet in the middle. The gradual melting of this ice sheet due to global warming is actually expected to increase Antarctic sea ice extent, due to freshening of the top layer of the Southern ocean.
The unexpected bit is what happened since 2016 of a sharply reduced Antarctic sea ice extent.
In addition, Antarctic SIE is at much lower latitudes compared to the Arctic. This also means that Antarctic SIE is "unlimited", as it is not constrained by surrounding landmasses, thus it grows much higher than Arctic SIE and is the principal component in the global SIE.
Bottom line, looking at decadal global SIE trends without diving into the components can be misleading as it lumps different processes together.
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on May 06, 2019, 11:44:32 AM
Ice loss between 1980s - 2010s is somewhat more than area of Spain and a bit less than area of Kenya, humanity has likely done greater amount of deforestation since 1980s. But these areas are by nature, of opposite signs. I've not seen a global graph that would sync the SH and NH areas by the received solar radiation, but this might be an exercise that could be done here. Just flip the SH values around at solstice points so you'll be close. The fact that SH might in fact take in more solar power for the higher ocean area might be ignored.
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on May 06, 2019, 03:07:13 PM
Nah, stupid of me to suggest inserting two points of non-congruence to a global year graph, might take some explaining.. Just delay the SH record for six months and sum it up with NH, or the other way around. Other option would be to sum up the anomalies on correct dates, this might show up the potential ENSO effect better than just the northern one (almost no predictability)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 06, 2019, 03:23:37 PM
Antarctic Sea Ice Extent reached its maximum value in the satellite record in 2014 at 27 million km2 after increasing very very gradually over the years.There were learned papers published saying this was expected. Why? Vast additional amounts of very cold fresh water entering the Southern Ocean from increased Antarctic Ice Sheet melt (as proved by the GRACE project and field studies), and floating on the ocean surface with the warmer denser salt water underneath. Hence much easier to freeze.

So when in 2016 Antarctic sea ice had crashed to a November maximum of 23.64 million km2 it was a surprise, and many assumed it was a blip. But this is the fourth year of very low sea ice. As yet I have not seen a convincing explanation for this apparent sea-change (duh). I bet AbruptSLR might have a reference or two, and hopefully by the end of summer GRACE-FO will give some new data on AIS mass loss.

Combined with Arctic Sea Ice (not changed that much) this has caused the large change in Global Extent in the last 4 years. See attached graph (if you believe the trendline, problem belong you).
Title: Re: Global sea ice area and extent data
Post by: Tor Bejnar on May 06, 2019, 03:24:39 PM
By the way: welcome to the ASIF, Roger (https://forum.arctic-sea-ice.net/index.php/topic,2136.msg198045.html#msg198045).
Title: Re: Global sea ice area and extent data
Post by: Tigertown on May 07, 2019, 05:34:32 PM
An ol' drunk stumbling off into the night; oh wait, that's the global SIE!
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F&hash=35d7d5d7526c9897dfb55501e320295a)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 08, 2019, 01:01:48 PM
JAXA Global Sea Ice Extent as at 7 May 2019 :-   19,253,124  km2

extent gain has been much above and much below average the last 6 days, but extent has remained lowest, now for the 28th day this year, 22 days in a row, 577 k below 2017.

- extent gain on this day 55k, 20k less than the the average gain of 75 k on this day,
- extent gain from minimum to date is 3.40 million km2, 1.82 million km2 (35%) less than the average gain of 5.23 milllion km2 by this day,
-on average 57.9% of extent gain done and 187 days to maximum, but before that there is a false maximum and minimum before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.45 million km2,  185k less than the record low maximum in 2016 and lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 11, 2019, 12:16:33 PM
JAXA Global Sea Ice Extent as at 10 May 2019 :-    19,856,896 km2

Extent gain has been more above than below average the last few days, but extent has remained lowest, now for the 31st day this year, 25 days in a row, 518 k below 2018.

- extent gain on this day 51k, 16k more than the the average gain of 35 k on this day,
- extent gain from minimum to date is 3.61 million km2, 1.74 million km2 (33%) less than the average gain of 5.35 milllion km2 by this day,
-on average 59.3% of extent gain done and 184 days to maximum, but before that there is a false maximum and minimum before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.53 million km2,  106k less than the record low maximum in 2016 and lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 19, 2019, 11:17:03 AM
JAXA Global Sea Ice Extent as at 18 May 2019 : 20,380,477 km2

Extent gain has been above and below average the last few days, but extent has remained lowest, now for the 39th day this year, 33 days in a row, 664 k below 2018.

- extent gain on this day 129k, 97k more than the the average gain of 32k on this day,
- extent gain from minimum to date is 4.13 million km2, 1.67 million km2 (29%) less than the average gain of 5.80 milllion km2 by this day,
-on average 64.3% of extent gain done and 170 days to maximum, but before that there is a false maximum and minimum before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.61 million km2,  a
 mere 31 k less than the record low maximum in 2016 and lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high.
Title: Re: Global sea ice area and extent data
Post by: Rich on May 19, 2019, 12:13:50 PM
Hooray for some gains. We're now only 1 state of Texas size equivalent short of the previous for this date.
Title: Re: Global sea ice area and extent data
Post by: Stephan on May 19, 2019, 01:45:16 PM
I use to compare the actual JAXA worldwide sea ice extent with the 2000-2009 average. Today it is -2,46 M km², almost seven times the size of Germany...
Title: Re: Global sea ice area and extent data
Post by: magnamentis on May 19, 2019, 06:50:19 PM
I use to compare the actual JAXA worldwide sea ice extent with the 2000-2009 average. Today it is -2,46 M km², almost seven times the size of Germany...

yeah it's good to look at and mention mid and long term comparisons before we get lost in tiny
seasonal talks  8)

how many times would that make the "Saarland" ? [just kidding]
Title: Re: Global sea ice area and extent data
Post by: b_lumenkraft on May 19, 2019, 07:29:16 PM
how many times would that make the "Saarland"?

(357.386km3/2.570km3)*7=973

That's almost a thousand Saarlands.
Title: Re: Global sea ice area and extent data
Post by: magnamentis on May 19, 2019, 07:59:46 PM
how many times would that make the "Saarland"?

(357.386km3/2.570km3)*7=973

That's almost a thousand Saarlands.

thanks. i opt for saarlands then, way more impressive numbers and then the size of the saarland is quite stable while the size of germany has been subject to significant changes over time LOL
Title: Re: Global sea ice area and extent data
Post by: Stephan on May 19, 2019, 09:00:20 PM
Off-topic:
For those who are not familiar with the 16 German states: Saarland is the smallest state within Germany (apart from the three "city states" Berlin, Hamburg and Bremen). Saarland joined Germany in 1957, eight years after the foundation of the Federal Republic of Germany.
Title: Re: Global sea ice area and extent data
Post by: b_lumenkraft on May 20, 2019, 09:20:23 AM
... and was French prior to that. And prior to that, it was German. And prior to that, it was French. And so on... You get the idea.
Title: Re: Global sea ice area and extent data
Post by: GoSouthYoungins on May 20, 2019, 10:29:37 PM
Back to actual global ice area and extent...

This time of year has historically seen the least variance from the mean. This year the area (in particular) and extent are drastically lower than ever before.

But hey, people say global sea ice doesn't matter. The northern and southern hemis are on different sides of a made up line, and the systems are some what separate. Who cares?

<snip, N.>
Title: Re: Global sea ice area and extent data
Post by: Neven on May 24, 2019, 11:17:48 AM
Two more days and everything will be back to normal again.

Right?
Title: Re: Global sea ice area and extent data
Post by: Juan C. García on May 24, 2019, 01:02:49 PM
Two more days and everything will be back to normal again.

Right?
Normal?
Well, it seems that the new normal is being the lowest (or second lowest) and out of the twice standard deviation range [which statistically, it is not normal].
Title: Re: Global sea ice area and extent data
Post by: magnamentis on May 24, 2019, 02:49:32 PM
Two more days and everything will be back to normal again.

Right?

if you consider the very lowest range of the bandwidth as normal, yes, nevertheless bad

[suppose you were kidding but just in case]
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 24, 2019, 02:57:31 PM
JAXA Global Sea Ice Extent as at 23 May 2019 :  20,842,190 km2

Low Arctic extent loss and high Antarctic extent gain the last few days, but extent has remained lowest, now for the 44th day this year, 38 days in a row, 486 k below 2017, 577k below 2018.

- extent gain on this day 141k, 90k more than the the average gain of 51k on this day,
- extent gain from minimum to date is 4.59 million km2, 1.46 million km2 (24%) less than the average gain of 6.06 milllion km2 by this day,
-on average 67.1% of extent gain done and 165 days to maximum, but before that there is a false maximum and minimum before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.81 million km2,  a
 174k more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high.
Title: Re: Global sea ice area and extent data
Post by: Neven on May 28, 2019, 11:33:25 AM
Dodge!
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 28, 2019, 11:58:32 AM
JAXA Global Sea Ice Extent as at 27 May 2019 :   20,954,768  km2

A change in the last 3 days. Very low Arctic extent loss increasing to average, and very high Antarctic extent gain decreasing to below average. Extent has remained lowest, now for the 48th day this year, 42 days in a row, 563 k below 2017, 581k below 2018.

- extent LOSS on this day 16k, 78k different from the the average gain of 62k on this day,
- extent gain from minimum to date is 4.71 million km2, 1.52 million km2 (24%) less than the average gain of 6.23 milllion km2 by this day,
-on average 69.0% of extent gain done and 161 days to maximum, but before that there is a false maximum and minimum before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.75 million km2,  113k more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on May 29, 2019, 06:46:44 AM
JAXA Global Sea Ice Extent as at 27 May 2019 :   20,954,768  km2

A change in the last 3 days. Very low Arctic extent loss increasing to average, and very high Antarctic extent gain decreasing to below average. Extent has remained lowest, now for the 48th day this year, 42 days in a row, 563 k below 2017, 581k below 2018.

This is a terrible situation. The planet continues to overheat. Each daily record increases the likelihood of the collapse of our fragile climate system.
Title: Re: Global sea ice area and extent data
Post by: roger white on May 29, 2019, 05:16:58 PM
The decadal figs given above your quote indicate either little or no decrease in sea ice from the 80's the 90's ( some days show an increase in global sea ice between those decades ) & a 2% decrease in sea ice over the past 40 years.
Do these stats justify your comments?
Do we have for example comparisons ( accurate ) of global sea ice changes between - say - the 1910's ^ the 1950's? To judge if a 2% swing is worth remarking upon? Or the 1880s - 1920's?
Or the 1840's to the 1880's?

Title: Re: Global sea ice area and extent data
Post by: jdallen on May 30, 2019, 03:41:15 AM
For the moment, I will assume your questions are in earnest rather than posting an invitation to start a fight.

The decadal figs given above your quote indicate either little or no decrease in sea ice from the 80's the 90's ( some days show an increase in global sea ice between those decades ) & a 2% decrease in sea ice over the past 40 years.
Do these stats justify your comments?
I will presume you are speaking to the graph in gerontocrat's post (#512)

The lines for those decadal averages merge like that because that is the middle of the transition between seasons - max at one end, minimum at the other.  There's been much more than a 2% decrease over 40 years.  That becomes more obvious as you follow the graph to mid-season - melt and refreeze - in late June and July.  There you can see the averages diverge by over 4 million km2 and more - a 15-20% decline - and that's before we begin to appreciate what's been happening since 2010.

I'm curious where you are deriving that 2% figure.


Do we have for example comparisons ( accurate ) of global sea ice changes between - say - the 1910's ^ the 1950's? To judge if a 2% swing is worth remarking upon? Or the 1880s - 1920's?
Or the 1840's to the 1880's?

"accurate" data that I think would satisfy your requirements is hard to come by before WW2.  There is some derived historical estimates, which really aren't bad, but have a fairly high uncertainty.  There's some discussion of that here:

https://www.carbonbrief.org/guest-post-piecing-together-arctic-sea-ice-history-1850

... from which even with that uncertainty, its very clear the ice has gone into a very serious decline.

Unfortunately information of a similar nature for the Antarctic is sparse to non-existent because of it's relative remoteness and very hazardous sea.
Title: Re: Global sea ice area and extent data
Post by: b_lumenkraft on May 30, 2019, 07:45:22 AM
The decadal figs given above your quote indicate either little or no decrease

Zoom out! > https://sites.google.com/site/pettitclimategraphs/sea-ice-volume

Do you see little to no decrease decade over decade there?
Title: Re: Global sea ice area and extent data
Post by: oren on May 30, 2019, 08:00:15 AM
b_l, the original question was about global sea ice extent, not just about the Arctic as in Pettit's graphs, although the advice itself is correct, zooming out will give better results. The back pages of this thread have Gerontocrat's graph at various points of the year, with decadal averages.

In any case, I remind again about the problematic nature of the global sea ice extent number, which is a combination of two very different figures. In NSIDC's (http://nsidc.org/arcticseaicenews/faq/#combined) words:
Quote
Why don’t you publish a global sea ice extent number?
The combined number, while easy to derive from our online posted data, is not useful as an analysis tool or indicator of climate trends. Looking at each region’s ice extent trends and its processes separately provides more insight into how and why ice extent is changing. Sea ice in the Arctic is governed by somewhat different processes than the sea ice around Antarctica, and the very different geography of the two poles plays a large role. Sea ice in the Arctic exists in a small ocean surrounded by land masses, with greater input of dust, aerosols, and soot than in the Southern Hemisphere. Sea ice in the Southern Hemisphere fringes an ice-covered continent, Antarctica, surrounded by open oceans. While both regions are affected by air, wind, and ocean, the systems and their patterns are inherently very different. Moreover, at any point in time, the two poles are in opposite seasons, and so a combined number would conflate summer and winter trends, or spring and autumn trends, for the two regions.
Title: Re: Global sea ice area and extent data
Post by: b_lumenkraft on May 30, 2019, 09:02:59 AM
the original question was about global sea ice extent

Damn, i missed that. Sorry folks.
Title: Re: Global sea ice area and extent data
Post by: Stephan on May 30, 2019, 10:29:42 AM
The decadal figs given above your quote indicate either little or no decrease in sea ice from the 80's the 90's ( some days show an increase in global sea ice between those decades ) & a 2% decrease in sea ice over the past 40 years.
[...]

If you go to JAXA (https://ads.nipr.ac.jp/vishop/#/extent/&time=2019-05-29%2000:00:00) and zoom in the month of May you will see a different behaviour of Arctic and Antarctic. Whereas the Arctic Sea Ice Extent is steadily reducing, the Antarctic Sea Ice Extent rose from the 80s, the 90s, the 00s and into 2014. If you build a sum of both, these differences average out for the 80s and the 90s. The 00s show a decline by about 0.3 M km², the 10s average is lower, due e.g. to the smaller 10s average since 2016 Antarctic Sea Ice Extent reached record lows.
Title: Re: Global sea ice area and extent data
Post by: Wipneus on May 31, 2019, 02:43:41 PM
NSIDC NT global sea ice area and extent both now  4 sigma below the 1981-2010 normal.

'long' graphs => you must click.
Title: Re: Global sea ice area and extent data
Post by: Tor Bejnar on May 31, 2019, 05:36:39 PM
Wipneus's graph suggests a 'transformation' may have occurred in 2015 or 2016 (2015 might show a low-ice expression of the pre-existing paradigm, given previously expressed variation, or a slide into a new paradigm), but the paradigm shift was solidified in late 2016.

Being Arctic centric in my thinking, the warm Arctic winter of 2016-17 (where DMI 80N temps (http://ocean.dmi.dk/arctic/meant80n.uk.php) show more High Arctic heat than ever before) suggests a NH cause.  However, there was also a shift in Antarctic ice extent: starting in 2016 (IIRC), winter max extent has started going down (where it had been slowly increasing).

So, was there a global paradigm shift at that time?
Title: Re: Global sea ice area and extent data
Post by: oren on May 31, 2019, 05:51:47 PM
4 SDs came from the terribly late refreeze of 2016-2017, and 4 SDs came from a phase change in the Antarctic (that is still with us).
The only possible global linkage I can think of is the Monster El Nino of 2016, but it could also be random - when you add together two not very related figures you could get what looks like a pattern but may be just noise.
Title: Re: Global sea ice area and extent data
Post by: bbr2314 on May 31, 2019, 06:57:34 PM
I would suggest both accumulation of heat in the High Arctic and the impact of clean energy (due to reduction in SO2 emissions) are dually to blame.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on May 31, 2019, 07:06:59 PM
As pointed out above, it is mostly about the Antarctic sea ice.. which after gradually increasingfor decades to a major max in 2014, seems to have experienced a sea-change.
Read all about it here (though I am not totally convinced)

Sustained ocean changes contributed to sudden Antarctic sea ice retreat in late 2016
https://www.nature.com/articles/s41467-018-07865-9

Title: Re: Global sea ice area and extent data
Post by: Observer on May 31, 2019, 07:43:42 PM
A comment from a member of the (hopefully) observant public on global extent: More than 2 years out of 40 continuously (almost) outside of 2 sigma (and all negative) seems unlikely to be random fluctuation or noise in the data--even if the data are simultaneously measuring 2 unrelated processes. Cause for concern? If I could not recall the times I have been wrong I wold vote for panic.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 01, 2019, 09:28:19 AM
JAXA Global Sea Ice Extent as at 31 May 2019 :    21,168,865  km2

In the last week very low Arctic extent loss increasing to average, and very high Antarctic extent gain decreasing to mostly below average. Extent has remained lowest, now for the 52 days this year, 46 days in a row.

Extent is 638 k below 2017, 695k below 2018.

- extent gain on this day 48k, 8k less than the the average gain of 48k on this day,
- extent gain from minimum to date is 4.92 million km2, 1.52 million km2 (24%) less than the average gain of 6.44 milllion km2 by this day,
-on average 71.3% of extent gain done and 161 days to maximum, but before that there is a false maximum and minimum before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.76 million km2,  120k more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 01, 2019, 09:39:39 AM
A comment from a member of the (hopefully) observant public on global extent: More than 2 years out of 40 continuously (almost) outside of 2 sigma (and all negative) seems unlikely to be random fluctuation or noise in the data--even if the data are simultaneously measuring 2 unrelated processes. Cause for concern? If I could not recall the times I have been wrong I wold vote for panic.

The reason is simple. The ocean begins to warm up with acceleration (in recent years and the average ocean level is growing much faster than before).
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 01, 2019, 09:50:15 AM
Being at opposite ends of the earth, as Arctic Sea Ice declines, Antarctic Sea ice increases, and vice versa. So twice a year the two extents cross each other. This is about to happen now.

So I thought let's have a look to see if there is a trend in the date this occurs. And the answer is - there was. The decadal averages show it happening earlier and earlier. This was presumably because Arctic sea ice was declining while Antarctic sea ice was very gradually increasing.

In 2017 to 2019 this clear trend has been messed up mainly due to the steep decline in Antarctic Sea Ice. See attached graph.

I will do a similar graph when Arctic Sea Ice increase overtakes Antarctic Sea Ice decline.
Title: Re: Global sea ice area and extent data
Post by: oren on June 01, 2019, 11:18:30 AM
A comment from a member of the (hopefully) observant public on global extent: More than 2 years out of 40 continuously (almost) outside of 2 sigma (and all negative) seems unlikely to be random fluctuation or noise in the data--even if the data are simultaneously measuring 2 unrelated processes. Cause for concern? If I could not recall the times I have been wrong I wold vote for panic.
The Arctic trend is very clear - downward. The Antarctic has been trending upwards and then crashed in late 2016. The combination appeared stable by coincidence, and then went to minus 8 sigma and stabilized at 4. This is what I meant by "noise", bad terminology, in reality the Antarctic has see a yet-unexplained major multi-sigma phase change, while the Arctic has not - it just went on declining.
I suggest a sigma graph for each region separately would clarify my load of words into something more coherent.
Title: Re: Global sea ice area and extent data
Post by: roger white on June 02, 2019, 02:51:00 PM
There are all sorts of very clever replies explaining why any increase in the antarctic sea ice is not significant, while the decrease in the arctic is very significant.
Yet the total for global sea ice which are published on this site continue to show:

No change ( sometimes tiny + or tiny -) in global sea ice between the 80's & 90's
2-3% decrease in global sea ice between the 80's & 2010's.

Contributors have confirmed there are no really accurate measures for global sea ice rise or fall in previous 40 year periods, to see if a 2-3% decrease is unusual.

So we seem to be left with observed very short term ( 40 years ) record of a decline in global sea ice of between 2 & 3%.

I wonder what, in a purely objective world, with no emotional commitment to hypotheses of warming, whether a scientific ( or indeed lay ) observer would make of such a trend.

Title: Re: Global sea ice area and extent data
Post by: Neven on June 02, 2019, 05:51:04 PM
Roger White, your comment smacks of climate risk denial, but maybe that's just my interpretation. Did you read Wipneus' comment and have a look at the graphs he posted:

NSIDC NT global sea ice area and extent both now  4 sigma below the 1981-2010 normal.

'long' graphs => you must click.

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=2136.0;attach=121656;image)

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=2136.0;attach=121657;image)
Title: Re: Global sea ice area and extent data
Post by: Sterks on June 02, 2019, 06:14:23 PM
There are all sorts of very clever replies explaining why any increase in the antarctic sea ice is not significant, while the decrease in the arctic is very significant.
Yet the total for global sea ice which are published on this site continue to show:

No change ( sometimes tiny + or tiny -) in global sea ice between the 80's & 90's
2-3% decrease in global sea ice between the 80's & 2010's.

Contributors have confirmed there are no really accurate measures for global sea ice rise or fall in previous 40 year periods, to see if a 2-3% decrease is unusual.

So we seem to be left with observed very short term ( 40 years ) record of a decline in global sea ice of between 2 & 3%.

I wonder what, in a purely objective world, with no emotional commitment to hypotheses of warming, whether a scientific ( or indeed lay ) observer would make of such a trend.
Arctic sea ice has been declining for 40 years and the scientific explanations based on AGW, albedo amplification, ocean heat input and MYI loss seem straightforward for a grade-5 level intellect (meaning Trump and his average follower could grasp it with a bit of brain exercise).
Antarctic sea ice is subject to very different constraints. It basically surrounds a huge ice sheet instead of being land-locked.
That is why I dislike mixing it with Arctic.
Scientists have provided AGW-based theories to explain apparent insensitivity and even increase of Antarctic sea ice over the years. Now SH sea ice extent has decided to go south, apparently disproving these AGW-based shifts of ocean and wind currents. I simply believe first order amplification of NH heat is absent in SH, and search of 2nd order effects is not for 5-grade brains and probably unimportant with respect to what goes on at the other side.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 02, 2019, 06:41:46 PM
So we seem to be left with observed very short term ( 40 years ) record of a decline in global sea ice of between 2 & 3%.
NO we are not.

If I had the energy I would go to skepticalscience.org, look at "most common deniers claims #10" and post some of the rebuttal. (https://skepticalscience.com/antarctica-gaining-ice.htm). But I can't be bothered.

But I will say,

The satellite record is 40 years, but the years between 80's average and 2010's averages is 30 years.
I do not get the 2-3% from the JAXA data. The change from 80's to 10's average..
Global sea ice extent maximum -6%,
Global sea ice extent minimum - 7%.
- Obviously the rate of change has accelerated remarkably in the last 4 years and does not show fully in the percents quoted above.. Currently global sea ice is at record lows again.

You also ignore the loss of mass from the Greenland and Antarctic ice sheets and the world's glaciers https://climate.nasa.gov/vital-signs/ice-sheets/.
But what's a few trillion tons in the world of denial ?

You also ignore the special characteristics of the Antarctic - the circumpolar current - that insulates the ice-cap, and recent events such as the ozone hole.

One could go on forever, but that's all I'm going to say about that.
Title: Re: Global sea ice area and extent data
Post by: jdallen on June 02, 2019, 08:24:12 PM
Roger White, your comment smacks of climate risk denial, but maybe that's just my interpretation. Did you read Wipneus' comment and have a look at the graphs he posted:

NSIDC NT global sea ice area and extent both now  4 sigma below the 1981-2010 normal.

http://file.scirp.org/Html/2-2801014_63707.htm

I think you'd find that increased total system enthalpy is responsible for the (temporary) increase seen in Antarctic ice... something that is counter-intuitive unless you study the science... and which will reverse quite as suddenly.
Title: Re: Global sea ice area and extent data
Post by: roger white on June 04, 2019, 05:15:08 PM
Which data are you using to get to the 6% decline in global sea ice from the 80's to 10's?
I am only calculating on the stats used on this site.

The latest post showed:
1980's 24,033,325
2010's 23,331...

3%.

Of course this varies from day to day. Other stats show 2-3% decline.

I'm not impressed by throwaway lines about " denial" or " sceptics."

My question simply follows the stats released on this forum. 
Title: Re: Global sea ice area and extent data
Post by: Neven on June 04, 2019, 10:47:29 PM
I'm not impressed by throwaway lines about " denial" or " sceptics."

How convenient, now you can just ignore my question and the graphs with the trend lines in 4SD territory.

Quote
Which data are you using to get to the 6% decline in global sea ice from the 80's to 10's?

Are words like 'maximum' and 'minimum' too complicated for you?
Title: Re: Global sea ice area and extent data
Post by: Michael Hauber on June 05, 2019, 01:38:52 AM

I wonder what, in a purely objective world, with no emotional commitment to hypotheses of warming, whether a scientific ( or indeed lay ) observer would make of such a trend.

No one is truly objective with no commitment to a particular hypothesis.  But I can at least claim to have been accused of being a denier in this forum on multiple occasions, whatever that may be worth in your opinion.

My opinion on the overall global sea ice trend is that it is pretty much what you expect in a world that is warming at a rate close to what was predicted some 40 years ago.  If you want to look at questions of whether the world is warming or not look at the global temperature trend, and not sea ice, which reflects temperature over a limited portion of the globe, and is also influenced by winds etc.  Its not a particularly important stat, and more interesting might be combined sea ice + snow cover, which then relates to global albedo, and one of several important feedbacks on global temperature change.  But important or not it is still interesting to look at from time to time.
Title: Re: Global sea ice area and extent data
Post by: oren on June 05, 2019, 03:28:44 AM
I wonder what, in a purely objective world, with no emotional commitment to hypotheses of warming, whether a scientific ( or indeed lay ) observer would make of such a trend.
Just to clarify: so in your opinion the global warming widely discussed is a hypothesis?
Title: Re: Global sea ice area and extent data
Post by: Ktb on June 05, 2019, 08:18:12 AM
Being 8σ from the mean is so insanely rare. It should occur NATURALLY once every 100 billion or so.

So what is more likely; that humans just happened to be here to witness a one in 100 billion chance, or that something else has tipped the scales forcing this event to occur?
Title: Re: Global sea ice area and extent data
Post by: DavidR on June 06, 2019, 04:06:54 AM
The latest post showed:
1980's 24,033,325
2010's 23,331...

3%.

Of course this varies from day to day. Other stats show 2-3% decline.

My question simply follows the stats released on this forum.
Roger, When we look at  the trend we generally consider the decline in the maxima and minima for the year rather than day to day values. As you can see in the table below based on these figures the decline in Global Maxima and Minima are both 7%.  However you can also see that the Arctic decline is much  greater than this at 41% for the minima and the Antarctic trend is actually an increase.

What  a reasonable person who knew nothing about AGW would say to this is "Why is it so?". 

The answer for the NH is seems obvious once you check the temperature records and discover that  both the Arctic and the Globe are warming rapidly. Obviously the more heat the less ice.

However in the Antarctic the picture is quite different Although the trend in temperatures is up there was a period from 1988 to about 2010 where the trend was flat or even in decline. A reasonable person will then ask why does this contradict expectations. As our temperature measures are consistently measured it is unlikely inaccurate measures are the reason. 

The two explanations I have heard are that:
a. ice melt water off the land is decreasing the salinity  of the water causing more freezing because fresh water freezes at a higher temperature than salt water.
b. the ozone hole that  was created in the 20Cent has changed the wind patterns so that stronger winds are blowing the ice further of the coast causing a greater extent.
Both these explanations are supported by relevant measurements.  But they may not be the complete answer. 

What we have seen since the 2015/6 El Nino is that Antarctic extent has dropped to extremely low levels, where only one day since Sept 9th 2016 has been ranked at 11 or above in the 31 year record. Prior to 2017 every year had at least 25 days ranked 20 or above.  So we appear to  be seeing a significant change.

PS. While you might not like being called a denier suggesting the Global warming is anything but a well documented fact is a clear sign of denial or ignorance. You can check out the temperature record here: http://www.woodfortrees.org/plot/ if you  actually are unaware of global temperature trends but don't try and dispute them here as Neven sensibly doesn't allow the forum to be corrupted by people arguing nonsense.
Title: Re: Global sea ice area and extent data
Post by: Dharma Rupa on June 06, 2019, 01:09:05 PM
I have read in passing that the circulation of the Southern Ocean has changed, but I don't really follow Antarctica so I don't know where I read about it.  I think that basically the surface current is more offshore and the next layer down is more onshore leading to more ice moving north in Winter and more melt under the ice shelves.  (A situation which cannot persist...)


Title: Re: Global sea ice area and extent data
Post by: roger white on June 06, 2019, 05:08:55 PM
Thanks to all for comments.

You seem to agree that on the stats regularly published on this site showing the decadal day to day changes, the figure is around 3% over 30 years from the satellite data.

But 7% or so when comparing maxima & minima.

Leaving aside all the snide comments, & responses to unasked questions- such as why the arctic decreases are quite large whereas the antarctic increases ( decadally) are also quite large - this still seems a small ( ish ) figure, without context of previous comparable measurements.

The comments that the picture has changed in the last 4 years seem remarkably silly. 4 years is no basis to measure such things. 30 years hardly seems very long..when there is no proper answer to the question.

Is a 3 or 7% variation unusual comparing several 30 year periods?

It also must seem suspicious that whenever a stat goes in the direction of a hypothesis ( the arctic ) the trend is real. But when it doesn't ( the antarctic ) special factors must be at play.



Title: Re: Global sea ice area and extent data
Post by: Neven on June 06, 2019, 09:14:37 PM
It has become quite clear now that Roger White didn't receive the climate risk denier memo that sea ice must be ignored. I don't think he has bought a new calendar since 2010 at least.  ;D

I'm willing to find out myself and get the data from NSIDC, but does anyone have Arctic minimum SIE+Antarctic minimum SIE, and the same for maximum? Just by eyeballing this graph the decrease seems to be at least 25% for the minimum:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.columbia.edu%2F%7Emhs119%2FUpdatedFigures%2FStorms_Fig20.gif&hash=9c0df2bddf0205be1f7231bc8640e983)

But even then, 7% in such a short time for something that normally takes place at geologic timescales (think ice ages), is quite mindblowing. Unless you have the mind of a climate risk denier that fits plenty of cognitive dissonance, that is.
Title: Re: Global sea ice area and extent data
Post by: oren on June 06, 2019, 11:19:13 PM
I've grown tired of this particular game.
Title: Re: Global sea ice area and extent data
Post by: Neven on June 07, 2019, 01:08:56 AM
I'm amazed that there are still climate risk deniers who play it. Again, didn't they get the memo on sea ice?  ::)

But to go back on-topic: Global sea ice area still lowest on record, extent by a larger margin.

Title: Re: Global sea ice area and extent data
Post by: DavidR on June 07, 2019, 04:44:19 PM
Thanks to all for comments.

You seem to agree that on the stats regularly published on this site showing the decadal day to day changes, the figure is around 3% over 30 years from the satellite data.

But 7% or so when comparing maxima & minima.

Leaving aside all the snide comments, & responses to unasked questions- such as why the arctic decreases are quite large whereas the antarctic increases ( decadally) are also quite large - this still seems a small ( ish ) figure, without context of previous comparable measurements.

The comments that the picture has changed in the last 4 years seem remarkably silly. 4 years is no basis to measure such things. 30 years hardly seems very long..when there is no proper answer to the question.

Is a 3 or 7% variation unusual comparing several 30 year periods?

It also must seem suspicious that whenever a stat goes in the direction of a hypothesis ( the arctic ) the trend is real. But when it doesn't ( the antarctic ) special factors must be at play.
Roger you seem to want a simple answer to a complex question. We don’t know for certain that this decline is unusual however we do know that their is no evidence suggesting it is not unusual. We do know that global warming is a fact not an hypothesis, and that decline in sea ice is a likely consequence of AGW. But the decline in the sea ice does not prove that AGW is occurring and it is not an objective of this forum to prove anything about AGW. We want to know what is happening with the ice and identify short term and long term causes. What are you trying to observe? Or are you just trying to waste our time by refusing to consider the answers you are given?  A reasonable person seeing the changes in the sea ice would sky “why is it so”, and when given reasonable answers would accept them or dispute them with evidence. You don’t seem to have any evidence to refute the responses you are given.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 07, 2019, 05:14:18 PM
The comments that the picture has changed in the last 4 years seem remarkably silly. 4 years is no basis to measure such things.

I think your opinion is an excellent proof of why a climatic catastrophe happens. Most people will regard climate change as random fluctuations until it is too late to change something. In connection, I think the creation of space colonies is the most sensible way solving climate problems.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 07, 2019, 06:24:59 PM
Now the global ice area is less than the past record of half a million square kilometers. This is the area of such a large country as France.

At this moment, I recall the following image:

(https://upload.wikimedia.org/wikipedia/commons/thumb/7/71/DESERTEC-Map_large.jpg/800px-DESERTEC-Map_large.jpg)

Each month, the anomalous area of ice this year adds several times more energy to climatic system than human civilization consumes.

This is a visual representation of the magnitude of climate change.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 07, 2019, 06:58:23 PM
I've grown tired of this particular game.
Me too. Nevertheless, worth a recap or two on the Antarctic Sea Ice thread since it was it happening there that is causing a scientist or three to scratch their heads.

Wait small (South Pacific Pidgin English)


Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 07, 2019, 07:08:00 PM
Nevertheless, worth a recap or two on the Antarctic Sea Ice thread since it was it happening there that is causing a scientist or three to scratch their heads.

Analysis of the latest archived data from the first meteorological satellites also says that the ice in Antarctica is decreasing:

https://diablobanquisa.wordpress.com/2018/09/13/antarctic_sea_ice_1960s_2018/

(https://diablobanquisa.files.wordpress.com/2018/09/ansie6717.png)

(https://diablobanquisa.files.wordpress.com/2018/09/ansie6717_winter_spring.png)
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 07, 2019, 07:10:38 PM
In addition, there are estimates from the first Antarctic researchers, who also speak of much more sea ice off the coast of Antarctica in the 19th century:

(https://tamino.files.wordpress.com/2010/10/shem140.jpg)
Title: Re: Global sea ice area and extent data
Post by: diablobanquisa on June 07, 2019, 09:39:13 PM
Nevertheless, worth a recap or two on the Antarctic Sea Ice thread since it was it happening there that is causing a scientist or three to scratch their heads.

Analysis of the latest archived data from the first meteorological satellites also says that the ice in Antarctica is decreasing:

https://diablobanquisa.wordpress.com/2018/09/13/antarctic_sea_ice_1960s_2018/

(https://diablobanquisa.files.wordpress.com/2018/09/ansie6717.png)
(https://diablobanquisa.files.wordpress.com/2018/09/ansie6717_winter_spring.png)


Thank you for linking to my blog post about Antarctic sea ice since the 1960s. Glad to see it is helpful!

I think that, although the almost flat trend for late November SIE during the multi-channel passive microwave satellite record becomes a slight negative trend when data from 1967 onward are incorporated to the record, this trend should be taken with caution due to the wider error margins in the earlier part of the record.
Overall, perhaps it would be safer to say that the trend in winter and spring Antarctic SIE during the last 50 years looks almost flat.



In addition, there are estimates from the first Antarctic researchers, who also speak of much more sea ice off the coast of Antarctica in the 19th century:

https://tamino.files.wordpress.com/2010/10/shem140.jpg

However, according to more recent estimates from the ship logbooks of explorers during 1897–1917 it seems that "summer sea ice edge was between 1.0 and 1.7° further north in the Weddell Sea during this period but that ice conditions were surprisingly comparable to the present day in other sectors."  https://www.the-cryosphere.net/10/2721/2016/ T. Edinburgh and J. J. Day: Estimating the extent of Antarctic summer sea ice during the Heroic Age of Antarctic Exploration

(https://diablobanquisa.files.wordpress.com/2016/11/image001.png?w=640&h=510)
Figure 4.The estimated DJFM Antarctic sea ice extent climatology for  the  period  1897–1917,  with  and  without  the  inclusion  of  the Worby and Comiso offset, is plotted alongside time series of DJFMmean sea ice extent calculated from HadISST2.2, NASA Team and NASA PM Bootstrap sea ice concentration datasets.


A closer comparison against the satellite era:
(https://diablobanquisa.files.wordpress.com/2016/12/antarctic_sea_ice_heroic_age_vs_satellite_data.png)
It seems that the most consistent values to be compared against the satellite era are those labelled as "with Worby&Comiso (https://www.sciencedirect.com/science/article/abs/pii/S0034425704001415) offset". Anyway, data from the early XXth century suggest a surprinsingly flat trend again. Perhaps the five decades without observations (1920-1970) could be hiding some multidecadal variability, who knows.



Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 08, 2019, 03:48:39 AM
Anyway, data from the early XXth century suggest a surprinsingly flat trend again.

Where do you see the flat trend?

Episodic data from the beginning of the 20th century and the 60s show that there was as much ice in Antarctica as in the record year 2014.

(https://diablobanquisa.files.wordpress.com/2018/09/uy.png?w=640)

For comparison, the Nimbus-1 worked only 25 days:

https://en.wikipedia.org/wiki/Nimbus_1
Quote
Nimbus 1 was launched on August 28, 1964, by a Thor-Agena rocket from Vandenberg Air Force Base, California, United States. The spacecraft functioned nominally until 22 September 1964.

That is, occasional first satellite observations in 1964 observed an almost record high ice area in Antarctica (compared to continuous near 40 year after 1979).

In this regard, the probability of a flat trend in Antarctica is almost zero. At 95%, the 100-year trend is associated with a decrease in ice area.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 08, 2019, 05:05:16 AM
Perhaps the five decades without observations (1920-1970) could be hiding some multidecadal variability, who knows.

In the Internet you can find data for the mid-20th century from whalers.

http://www-das.uwyo.edu/~geerts/cwx/notes/chap11/sea_ice.html
Quote
Whalers' logbooks dating from as early as the early 20th century provide anecdotal evidence. At southern whaling stations the ice cover has decreased by about 25% between 1950 and 1975, i.e. -10% per decade (2).

https://www.comnap.aq/SiteAssets/SitePages/SeaIceWorkshop/Public_Worby.pdf
The graph from this presentation from 22 pages is especially visual.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 08, 2019, 05:22:38 AM
Taking into account data on the Arctic.

In general, the global ice area over the past 100 years has decreased by about 20%. The lion's share of this reduction occurred in recent decades.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 08, 2019, 10:41:03 AM
Which data are you using to get to the 6% decline in global sea ice from the 80's to 10's?
I am only calculating on the stats used on this site.

The latest post showed:
1980's 24,033,325
2010's 23,331...

3%.

You misjudge. It is important to consider Area, not Extent.

I have now downloaded the latest data from here.
https://sites.google.com/site/arctischepinguin/home/global-sea-ice
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_global_nt_final_and_nrt.txt.gz?attredirects=0

And got the following values for decades:

80s 19,00
90s 18,81
00s 18,34
10s 17,72

So in reality, the fall in the last 40 years is 7%.

Approximately the same amount of lost snow cover is estimated.
https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter4-1.pdf

Quote
Over the longer 1922 to 2005 period (updated from Brown, 2000), the linear trend in March and April NH SCA (Figure 4.2) is a statistically significant reduction of 2.7 ± 1.5 × 10^6  km2 or 7.5 ± 3.5%.

This means the planet receives a huge amount of additional heat.
Title: Re: Global sea ice area and extent data
Post by: diablobanquisa on June 08, 2019, 10:57:06 AM
That is, occasional first satellite observations in 1964 observed an almost record high ice area in Antarctica (compared to continuous near 40 year after 1979).

"However, in August 1966 the maximum sea ice extent fell to 15.9x10km± 0.3x10km. This is more than 1.5x10km below the passive microwave record of 17.5x10km set in September of 1986."

Gallaher & Garret Campbell, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140017193.pdf

That is, occasional first satellite observations observed an almost record high in 1964, but a record low in 1966. Both should be taken into account.



https://www.comnap.aq/SiteAssets/SitePages/SeaIceWorkshop/Public_Worby.pdf
The graph from this presentation from 22 pages is especially visual.

That graph shows data from De la Mare 1997.
However, regarding De la Mare data, Ackley et al. stated: "Our work showed a consistent summer offset (November‐December), with the ship‐observed ice edge 1 ‐ 1.5° north of the satellite‐derived ice edge. We further reexamine the use of whale catch as an ice edge proxy where agreement was claimed between the satellite ice edge (1973‐1987) and the ship whale catch positions. This examination shows that, while there may be a linear correlation between ice edge position and whale catch data, the slope of the line deviates from unity and the ice edge is also further north in the whale catch data than in the satellite data for most latitudes. We compare the historical (direct) record and modern satellite maps of ice edge position accounting for these differences in ship and satellite observations. This comparison shows that only regional perturbations took place earlier, without significant deviations in the mean ice extents, from the pre‐1950s to the post‐1970s. This conclusion contradicts that previously stated from the analysis of whale catch data that indicated Antarctic sea ice extent changes were circumpolar rather than regional in nature between the two periods."
Ackley et al. 2003 https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1751-8369.2003.tb00091.x

Worby&Comiso 2004 (https://www.sciencedirect.com/science/article/abs/pii/S0034425704001415) describe the offset between ship observed sea ice edge and the sea ice edge derived from passive microwave data too. This offset must be taken into account when comparing ship observations with passive microwave satellite observations. That is the reason why Edinburgh and Day (https://www.the-cryosphere.net/10/2721/2016/) present their data with the "Worby&Comiso" offset. If you compare the ship observations from 1897-1917 (taking into account the offset) with the passive microwave satellite observations from 1973 onward, results are rather similar (despite regional variations, i.e. more ice at the Weddell Sea one century ago).

Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 08, 2019, 11:29:39 AM
regional perturbations took place earlier, without significant deviations in the mean ice extents, from the pre‐1950s to the post‐1970s

Naturally, this data is not as accurate as satellite. But they are the most accurate of the pre-satellite era.

The number of whaling expeditions many times exceeds the number of scientific expeditions of the beginning of the 20 century. Compare:

https://www.the-cryosphere.net/10/2721/2016/tc-10-2721-2016.pdf

Quote
Data from 185 whaling expeditions (mostly Norwegian but some from English whaling logbooks) were used as its basis (H. Titchner, personal communication, 2016).

1931 to 1987 - 56 years old

against the data of only 11 scientific expeditions for only 20 years old (1897-1917).

16124  records about ice edge against 191 (84 times difference).

In general, data on the secular decrease in the area of ice around Antarctica is much more than on the zero trend. This is a trivial statistic.

It is likely that the authors of the last work added an epithet ("heroic times") to somehow diminish this comparison (the authors wanted a sensation that the ice does not melt because of AGW?). Although James Cook experienced much greater hardship at the end of the 18th century, when he could not get through to the shores of Antarctica at all.

That is, occasional first satellite observations observed an almost record high in 1964, but a record low in 1966. Both should be taken into account.

I think there are no big contradictions. Probably between 1964 and 1966, there was a major decrease in the ice area. This is similar to the difference between 2014 and 2016 in Antarctica or the difference between 2012 and 2013 in the Arctic.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 08, 2019, 12:35:17 PM
An additional advantage of whaler's observations is the fact that they ply along the edge of the ice, where whales like to rest. And scientific expeditions, on the contrary, quickly cross the ice edge.

In this regard, there are data for Svalbard even for 400 years:

https://link.springer.com/article/10.1007/s00300-014-1482-1
Quote
The position of the ice edge (the gray vertical bars) in August between Svalbard and Franz Josef Land for the period 1553–2012, given as the mean latitude within the sector 20–45°E (modified after Vinje 1999 and updated to summer 2012).

(https://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1504.0;attach=101884;image)

These data confirm that the most severe iсe conditions were around 1780. Unhappy James Cook found himself at the wrong time, in the wrong place. He could not pass the northwest passage (he did not even reach Barrow), nor make his way to the shores of Antarctica.

Just imagine what a crazy amount of ice we have lost in the last 200 years due to anthropocentric global warming!

And of course you can imagine what will happen to the whales when all sea ice melts (this will happen very soon). They can cool more, and are likely to become extinct like polar bears despite protective measures in recent decades.
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 08, 2019, 12:51:54 PM
(he did not even reach Barrow)

Research ships were able to break through the ice to Cape Barrow only after 40 years!

https://en.wikipedia.org/wiki/Frederick_William_Beechey

Quote
In 1825, Beechey was appointed to command HMS Blossom. His task was to explore the Bering Strait in concert with Franklin and Parry operating from the east. In the summer of 1826, he passed the strait and a barge from his ship reached 71°23'31" N., and 156°21'30" W. near Point Barrow which he named, a point only 146 miles west of that reached by Franklin's expedition from the Mackenzie River.

Exactly in the same decade, the first ships were able to break through the ice to the shores of Antarctica! Now this sounds surprising due to the fact that most of the coast of Antarctica in summer are freed from sea ice.

Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 08, 2019, 01:00:05 PM
JAXA Global Sea Ice Extent as at 7 June 2019 :    21,168,865  km2

Back to what's happening this year

In the last week Arctic extent loss was more above average than below, but most days saw high Antarctic extent gain. But extent has remained lowest, now for 59 days this year, 53 days in a row.

Extent is 744 k below 2017, 599 k below 2018.

- extent gain on this day 93 k,37 k more than the the average gain of 56k on this day,
- extent gain from minimum to date is 5.39 million km2, 1.46 million km2 (21%) less than the average gain of 6.85 milllion km2 by this day,
-on average 75.9% of extent gain done and 150 days to maximum, but before that there is a false maximum (in July) and a false minimum (in September) before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.81 million km2,  173k more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high. Confidence in any projection is even lower than normal.
Title: Re: Global sea ice area and extent data
Post by: FishOutofWater on June 08, 2019, 10:31:35 PM
Roger, you might consider taking your own advice:

"Leaving aside all the snide comments, & responses to unasked questions- such as why the arctic decreases are quite large whereas the antarctic increases ( decadally) are also quite large - this still seems a small ( ish ) figure, without context of previous comparable measurements.

The comments that the picture has changed in the last 4 years seem remarkably silly. "

I don't care about your opinion about what the changes in the Antarctic over the last 4 years. You have demonstrated no competence in analyzing what the sudden loss of large quantities of sea ice means. I suspect that few other people care about your opinion.

If you presented a cogent analysis of what has changed and what has not over the past 4 years in Antarctic waters your opinion might be more interesting. If you cited papers about why the sea ice extent expanded for several decades before the sudden reversal, you opinion might be based on something more than an assertion. But it's not, perhaps because you aren't interested in the science. You appear to have a political agenda.

When a natural system makes a sudden unexpected shift, most scientists want to know why. Thre's nothing silly about the sudden drop in sea ice around Antarctica.
Title: Re: Global sea ice area and extent data
Post by: Shared Humanity on June 08, 2019, 11:00:43 PM
JAXA Global Sea Ice Extent as at 7 June 2019 :    21,168,865  km2

Back to what's happening this year


Awww.... I was beginning to enjoy those graphs with no data points.  ;)
Title: Re: Global sea ice area and extent data
Post by: ArcticMelt2 on June 09, 2019, 06:30:58 AM
I don't care about your opinion about what the changes in the Antarctic over the last 4 years. You have demonstrated no competence in analyzing what the sudden loss of large quantities of sea ice means. I suspect that few other people care about your opinion.

By the way, I yesterday looked at trends in the monthly NSDIC data. In November, the trend has already become zero. Such a stupid 4 years.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 09, 2019, 11:53:08 AM
JAXA Global Sea Ice Extent as at 7 June 2019 :    21,168,865  km2
Back to what's happening this year

Awww.... I was beginning to enjoy those graphs with no data points.  ;)
Ok, just for you this what I wrote about Antarctic sea ice on the Antarctic sea ice thread
___________________________________________________________________
So here is a reprise of the story of Antarctic sea ice in the satellite record that I have gleaned mainly from the ASIF and links provided by it.

From 1979 to to about 2010 the general trend of Antarctic Ice was to increase very very slowly - a glacial pace indeed.
Then until the maximum maximum of 2014 and maximum minimum of 2013 the sea ice seemed to be increasing faster. The minimum grew at an even faster pace in percentage terms  than the max.
WHY?
Scientists, including Hansen noted that the GRACE project showed that Antarctic Mass Loss (due to ice sheet loss) was increasing at an ever increasing rate. The result - a growing flood in the Southern summer of very cold FRESH water spreading out over the surrounding Southern Ocean, sitting as a layer on top of warmer but denser salt water. The freezing point of freshwater is higher than of salt water - hence sea ice growing.

BUT
From 2014 to 2018 the sea ice maximum dropped by 10%.
From 2013 to 2018 the sea ice minimum dropped by 40%.

It is possible that in 2019 the maximum will drop by another 4 %

What's going on?
The paper quoted below talks about 2016 and 2017. The change happened earlier and seems to be still happening. So since our knowledge of what's going on in Antarctica and why is inversely proportional to the size of the place under examination, the answer that belongs to me is a resounding - don't know.

We do know the air is heating,
We do know the oceans are heating,
We do know the Antarctic Ice Sheet , glaciers and ice shelves are melting.

And the area covered by sea ice is shrinking.

And that is definitely, absolutely all I'm going to say about that.
___________________________________________________
https://www.nature.com/articles/s41467-018-07865-9
Quote
Discussion
The evidence indicates that the rapid decrease in Antarctic sea ice
extent in late 2016 and the significant changes in the upper
Southern Ocean were likely caused by three factors. First, record
SST, precipitation, and convective heating anomalies in the
eastern tropical Indian and far-western Pacific Oceans produced
an anomalous Rossby wave response in the mid- and high
southern latitudes in SON 2016. The consequent teleconnection
pattern around Antarctica was characterized by a record negative
phase of the SAM, and a preponderance of warm, moist southward
surface winds that drove sea ice southwards and produced
decreased sea ice extent. Second, the anomalous surface winds
associated with this teleconnection pattern were also associated
with positive wind stress curl anomalies, southward Ekman
transport, and warmer surface water transported southward.
Third, a decadal timescale trend of negative wind stress curl
anomalies over the 2000s, associated with the positive trend of the
SAM and the negative phase of the IPO, moved warmer subsurface
water in the Southern Ocean upward in the column (part
of the so-called two-timescale response22–24). Then in late 2016,
the negative SAM contributed to producing anomalously warm
SSTs such that the entire upper 600m (over many areas of the
Southern Ocean) then was characterized by positive temperature
anomalies. These warmer ocean temperatures, combined with
the direct effects of surface wind forcing on the sea ice, produced
the rapid decrease of Antarctic sea ice extent. These conditions
were maintained through 2017, with reduced sea ice extent
compared to the average of the 2000s through JJA 2018.
Title: Re: Global sea ice area and extent data
Post by: roger white on June 10, 2019, 08:38:37 AM
Thanks for all the comments. Of course all phenomena merit investigating, even 4 years of shrinking antarctic sea ice. Though surely this is too short a period for anyone to jump to conclucions.
Indeed the satellite record is very short surely when measuring the planet's climate.
My main point though remains. On it's own the decrease in global sea ice totals reported on this forum is.. ( 3% day to day -7% on other measures as pointed out ) from the 80's to the 2010's.
I'm now clear on that.

<snip, you're lagging again, the Hiatus BS is no longer a serious climate risk denier argument; N.>
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on June 10, 2019, 04:43:36 PM
Here are the current (20190609) graphs of Global Ice Area and Extent. The about 1,5Mkm2 losses on both measures equates to a bit smaller loss than area of Alaska or 2,5 Texases. If the ice lost was ~4 inches thicc the energy required for the melt would be quite a lot. The calculation of the exact amount is left as an excersice to those who think pouring steaming water on growing crops is a good idea.
Title: Re: Global sea ice area and extent data
Post by: Tony Mcleod on June 12, 2019, 09:38:38 PM
Ok, I'm calling it: we've reached the max, maybe for the year, maybe longer. :o

(https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_area_byyear_b.png)
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 13, 2019, 06:56:47 AM
JAXA Global Sea Ice Extent as at 12 June 2019 :     22,003,693  km2

In the last week Arctic extent loss was below average, and most days saw high Antarctic extent gain. But extent has remained lowest, now for 64 days this year, 58 days in a row.

Extent is 440 k below 2017, 931 k below 2018.

- extent gain on this day 69 k,30 k more than the the average gain of 39 k on this day,
- extent gain from minimum to date is 5.75 million km2, 1.35 million km2 (19%) less than the average gain of 7.11 milllion km2 by this day,
-on average 78.8% of extent gain done and 145 days to maximum, but before that there is a false maximum (in July) and a false minimum (in September) before the (usually) true maximum around the 4th of November.

The Perils of Projections
- last 10 years average remaining extent gain would give a maximum of 23.92 million km2,  282 k more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high. Confidence in any projection is even lower than normal. In contrast with JAXA extent data, NSIDC Global Arctic Area in contrast shows a sharp drop, but I think it is premature to call the false maximum this early as in the previous post. We will see how the data develops over the next few days.
Title: Re: Global sea ice area and extent data
Post by: grixm on June 13, 2019, 03:37:54 PM
Hi, first post on this forum. I think I might get addicted.

Not sure if it has been posted before, but I saw that yesterday the NSIDC sea ice extents on both the arctic and antarctic individually were the lowest in the satellite era on this date.

https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: Global sea ice area and extent data
Post by: Rod on June 13, 2019, 05:40:58 PM
This is area, not extent, but I thought these tweets from Kevin Pluck over the last four days pretty much sum up where we are right now. 
Title: Re: Global sea ice area and extent data
Post by: be cause on June 13, 2019, 06:12:49 PM
tomorrow .. OMFG !!! ? B.C.
Title: Re: Global sea ice area and extent data
Post by: oren on June 13, 2019, 07:17:13 PM
Hello and welcome, grixm. And yes, you are correct.
Title: Re: Global sea ice area and extent data
Post by: Tony Mcleod on June 14, 2019, 06:08:10 AM
it is premature to call the false maximum this early as in the previous post. We will see how the data develops over the next few days.

I remember watching with morbid fascination as 2016 drifted on lower and lower into uncharted σ territory. That year's "false maximum" was the maximum. I thought at the time this is exactly the kind of 'flutter' you'd see as a system flips towards a new attractor and if that is what is happening, it is such a titanic system (see what I did there), there is no way its flipping back anytime soon.

Weird is the new normal so I won't be surprised if 2019 is a repeat of 2016 or even a new low. Thats a big June fall to climb back out of.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 14, 2019, 08:15:44 AM
While NSIDC Area shows a collapse in total area, JAXA extent numbers show well above average daily increases in extent. Quite a disconnect and growing.
Title: Re: Global sea ice area and extent data
Post by: Tony Mcleod on June 14, 2019, 08:36:25 AM
Any ideas about the disconnect? The two seem at odds.
Title: Re: Global sea ice area and extent data
Post by: RikW on June 14, 2019, 11:44:30 AM
I'd say it's because of ice breaking up in smaller floes and spreading increases so more parts of the grid that have at least 15% ice cover, thus higher extent.

At the short time that creates a gap between extent and area, because there are more parts with some ice while in the longer term it will be disastrous for the ice, many small parts is more open sea, so more heat that can be trapped and more ice that is probably easy to melt, because of the smaller parts.

Do I guess we will see a cliff in extent in the near future because those small parts will probably disappear
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 14, 2019, 12:12:34 PM
Any ideas about the disconnect? The two seem at odds.

From reading the Arctic melting thread recently and in years past, this variation may also be partly because of strong melt ponding in some parts of the Arctic. It seems this confuses the sensors to assume open water though the ice is still there. The JAXA sensor uses much finer resolution than the older NSIDC sensor, and is much newer technology. Perhaps the JAXA sensor is less likely to be fooled by this ponding and in smaller areas.

However, normally such discrepancies tend to iron out somewhat over a longer period. So perhaps as regards the NSIDC data, one swallow does not make a summer? (or the JAXA data is behind the curve).

patiencia, calma...
Title: Re: Global sea ice area and extent data
Post by: Tony Mcleod on June 15, 2019, 12:42:23 PM
tomorrow .. OMFG !!! ? B.C.

really...

(https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc_global_area_byyear_b.png)

Title: Re: Global sea ice area and extent data
Post by: Tony Mcleod on June 16, 2019, 10:42:43 AM
patiencia, calma...

Hmm i don't think humans are ever going to see 18m sq km of seaice area again.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 16, 2019, 04:03:18 PM
No JAXA data, so here is the NSIDC Global daily (NOT 5 day) extent.

Note the 1980's wobbles, caused by NSIDC only posting data once every 2 days until the late 1980's. Even using a cleverer average formula (combining sum and countif) will not fix it. Never mind, the message is still clear.

I am not writing off more than 18 million km2 area as a late October / early November maximum, though each day seems to make a really low maximum more probable on both measures.
Title: Re: Global sea ice area and extent data
Post by: oren on June 16, 2019, 04:38:55 PM
First, you fill in the 1980s missing data days by averaging the previous day and the next day's data. Then the way is clear.
Title: Re: Global sea ice area and extent data
Post by: Pmt111500 on June 16, 2019, 04:51:43 PM
First, you fill in the 1980s missing data days by averaging the previous day and the next day's data. Then the way is clear.

Linear interpolation is the way to go in CO2 missing days as well, they've become rather sparse normally, but still there might be some missing weeks..
Title: Re: Global sea ice area and extent data
Post by: interstitial on June 16, 2019, 05:44:11 PM
I wrote a script in vba for excel to clean up the data. It wouldn't be acceptable for a formal research paper but for our purposes it works.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 16, 2019, 08:00:31 PM
First, you fill in the 1980s missing data days by averaging the previous day and the next day's data. Then the way is clear.

Linear interpolation is the way to go in CO2 missing days as well, they've become rather sparse normally, but still there might be some missing weeks..
The penny dropped on how to do it almost all at once instead of plonking in the formula empty cell by empty cell .

make a copy of the data sheet.
In the copy look at each cell of the original data.
   If zero or blank, do the interpolation.
   If there is data, copy that into the copy.
Clean up any odd bits.
Then copy your copy sheet back into the original sheet as numbers (not with formulas).

- and the wobbles have gone
Title: Re: Global sea ice area and extent data
Post by: oren on June 17, 2019, 03:48:33 AM
Happy to help 8)
Title: Re: Global sea ice area and extent data
Post by: Peter Ellis on June 17, 2019, 12:51:35 PM
patiencia, calma...

Hmm i don't think humans are ever going to see 18m sq km of seaice area again.
This is a bit silly.  Apart from one exceptional year, the Nov peak is always higher than the June peak, and the June peak was over 18m.
Title: Re: Global sea ice area and extent data
Post by: Tony Mcleod on June 17, 2019, 01:47:11 PM
patiencia, calma...

Hmm i don't think humans are ever going to see 18m sq km of seaice area again.
This is a bit silly.  Apart from one exceptional year, the Nov peak is always higher than the June peak, and the June peak was over 18m.

I think it is silly to assume we are only going to see one exceptional year.
Title: Re: Global sea ice area and extent data
Post by: Peter Ellis on June 17, 2019, 09:03:41 PM
patiencia, calma...

Hmm i don't think humans are ever going to see 18m sq km of seaice area again.
This is a bit silly.  Apart from one exceptional year, the Nov peak is always higher than the June peak, and the June peak was over 18m.
I think it is silly to assume we are only going to see one exceptional year.
True, but for your "never again" to be true, you're expecting every year from now on to be exceptional....
Title: Re: Global sea ice area and extent data
Post by: Tony Mcleod on June 18, 2019, 06:43:51 AM
patiencia, calma...

Hmm i don't think humans are ever going to see 18m sq km of seaice area again.
This is a bit silly.  Apart from one exceptional year, the Nov peak is always higher than the June peak, and the June peak was over 18m.
I think it is silly to assume we are only going to see one exceptional year.
True, but for your "never again" to be true, you're expecting every year from now on to be exceptional....


Is it "silly" to be expecting a BOE this year? I don't think so. I agree that is not the most likely outcome for this NH summer, but also not impossible. The year after? The year after that? Many here would be happy if we can kick the BOE can down the road for that long. After a BOE would I contend every year from then on would "be exceptional".

Just taking another look at the graph I would say it is 50/50 as to whether 18m km will be topped again this year and if that were the outcome then next year the odds would be even longer.
Yes, all idle speculation.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 19, 2019, 08:59:34 AM
JAXA Global Sea Ice Extent as at 18 June 2019 :      22,403,886 km2

In the last 2 weeks Arctic extent loss was well below average, and while Antarctic extent gain was up and down around the average. Extent has remained lowest, now for 70 days this year, 64 days in a row.

Extent is 242 k below 2017, 730 k below 2018.

- extent gain on this day 56 k, 7 k more than the the average gain of 49 k on this day,
- extent gain from minimum to date is 6.15 million km2, 1.24 million km2 (17%) less than the average gain of 7.11 milllion km2 by this day,
-on average 81.9% of extent gain done and 139 days to maximum, but before that there is a false maximum (in July) and a false minimum (in September) before the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.04 million km2,  402 k more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high. Confidence in any projection is even lower than normal. However, the JAXA extent data so far does not point to a change to the usual pattern of a false maximum in July, a false min in Aug/Sep and a final max in early November.
Title: Re: Global sea ice area and extent data
Post by: gerontocrat on June 22, 2019, 07:19:52 AM
JAXA Global Sea Ice Extent as at 21 June 2019 :  22,578,517 km2

In the last 2 weeks Arctic extent loss was well below average, and while Antarctic extent gain was up and down around the average. Extent remained lowest, now for 72 days this year, 66 days in a row.

But the last 3 days saw very high Antarctic Sea Ice gain, while in 2017 for those 3 days global extent dropped. As a result Global extent is now in 2nd place, 12 k above 2017, but 849 k below 2018.

- extent gain on this day 56 k, 26 k more than the the average gain of 30 k on this day,
- extent gain from minimum to date is 6.33 million km2, 1.13 million km2 (15%) less than the average gain of 7.46 milllion km2 by this day,
-on average 82,7% of extent gain done and 136 days to maximum, but before that there is a false maximum (in July) and a false minimum (in September) before the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.14 million km2,  0.5 million km2 more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Being a combination of two separate pieces of data volatility is often very high. Confidence in any projection is even lower than normal. However, the JAXA extent data so far does not point to a change to the usual pattern of a false maximum in July, a false min in Aug/Sep and a final max in early November.
Title: Re: Global sea ice area and extent data
Post by: Ktb on June 23, 2019, 05:42:07 PM
patiencia, calma...

Hmm i don't think humans are ever going to see 18m sq km of seaice area again.

back over 18 million km^2 we go!
Title: Re: Global sea ice area and extent data
Post by: Paddy on June 24, 2019, 10:39:09 PM
patiencia, calma...

Hmm i don't think humans are ever going to see 18m sq km of seaice area again.

I'm pretty certain we'll see 19 again, and would be surprised if we don't see 20 again.  Neither the arctic nor the antarctic trend is smooth enough to predict steady loss year on year from here onwards.