Author Topic: Global sea ice area and extent data (Read 573812 times)

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.

Tigertown · « **Reply #1 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.

Tigertown · « **Reply #2 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.

Tigertown · « **Reply #3 on:** August 14, 2017, 04:17:44 PM »

Down another 48,000 km² per NSIDC, leaving the total at 22.347 x 10⁶.

gerontocrat · « **Reply #4 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

Tigertown · « **Reply #5 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.

Tigertown · « **Reply #6 on:** August 16, 2017, 05:36:30 AM »

JAXA extents add up to 22,226,175 km². Down ever so little.

Tigertown · « **Reply #7 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.

Tigertown · « **Reply #8 on:** August 17, 2017, 06:35:33 AM »

JAXA lands at 22,225,953 km², down by a mere 222 km².

gerontocrat · « **Reply #9 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.

Quote from: gerontocrat on August 15, 2017, 12:22:13 PM

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........

Tigertown · « **Reply #10 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.

Tigertown · « **Reply #11 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.

Tigertown · « **Reply #12 on:** August 19, 2017, 04:29:26 PM »

NSIDC totals to 22.44 x 10⁶ km² for the 18th. Down 43k.

Tigertown · « **Reply #13 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.

gerontocrat · « **Reply #14 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.

Tigertown · « **Reply #15 on:** August 21, 2017, 02:53:13 PM »

NSIDC totals in at 22.514 x 10⁶ km².

Tigertown · « **Reply #16 on:** August 22, 2017, 01:56:47 PM »

NSIDC totals for the 21st add up to 22.609 x 10⁶ km².

gerontocrat · « **Reply #17 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.

Tigertown · « **Reply #18 on:** August 23, 2017, 03:40:17 PM »

NSIDC totals for the 22nd add up to 22.774 x 10⁶ km2.

gerontocrat · « **Reply #19 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.

Tigertown · « **Reply #20 on:** August 24, 2017, 03:25:49 PM »

NSIDC totals for the 23rd add up to 22.759 x 10⁶ km². Actually down slightly.

Tigertown · « **Reply #21 on:** August 25, 2017, 03:19:04 PM »

NSIDC totals for the 24th add up to 22.694 x 10⁶ km². Down 65 k.

Tigertown · « **Reply #22 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.

Tigertown · « **Reply #23 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.

gerontocrat · « **Reply #24 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?

gerontocrat · « **Reply #25 on:** August 28, 2017, 02:39:11 PM »

Jaxa global extent down 60 on 27th August entirely due to extent loss in the Antarctic.

Tigertown · « **Reply #26 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.

Tigertown · « **Reply #27 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???

Tigertown · « **Reply #28 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.

Tigertown · « **Reply #29 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.

Tigertown · « **Reply #30 on:** August 30, 2017, 02:08:06 PM »

NSIDC comes in at 22.584 x 10⁶ km² for the 29th. Down ever so little.

Tigertown · « **Reply #31 on:** August 31, 2017, 02:37:14 PM »

NSIDC comes in at 22.597 x 10⁶ km² for the 30th. Up slightly.

Tigertown · « **Reply #32 on:** September 01, 2017, 02:58:58 PM »

NSIDC comes in at 22.537 x 10⁶ km² for the 31st. Down 60k.

Tigertown · « **Reply #33 on:** September 02, 2017, 10:35:40 AM »

JAXA comes in at 22,143,633 km² for Sept. 1st. Down in both hemi's.

Tigertown · « **Reply #34 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.

Tigertown · « **Reply #35 on:** September 04, 2017, 06:34:17 AM »

JAXA comes in at 22,114,192 km² for the 3rd.

Tigertown · « **Reply #36 on:** September 04, 2017, 01:48:20 PM »

NSIDC SIE totals are up by 14k to 22.367 x 10⁶ km².

Tigertown · « **Reply #37 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.

Tigertown · « **Reply #38 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.

Tigertown · « **Reply #39 on:** September 11, 2017, 03:55:44 PM »

NSIDC is at 22.558 x 10⁶ km² for the 10th.

Tigertown · « **Reply #40 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.

Tigertown · « **Reply #41 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.

gerontocrat · « **Reply #42 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).

Tigertown · « **Reply #43 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.

Tigertown · « **Reply #44 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.

charles_oil · « **Reply #45 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.

Tigertown · « **Reply #46 on:** September 18, 2017, 08:11:18 AM »

Quote from: 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.

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.

Tigertown · « **Reply #47 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.

oren · « **Reply #48 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.

Tigertown · « **Reply #49 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.

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Author Topic: Global sea ice area and extent data (Read 573812 times)