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Arctic Sea Ice Extent, Area, and Volume


ORH_wxman
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On 7/5/2022 at 9:48 AM, ORH_wxman said:

Update:

On 7/1, the NSIDC SIA sootd at 7.07 million sq km. Here's how other years compared on the same date:

2021: -70k

2020: -510k

2019: -450k

2018: +320k

2017: +10k

2016: -240k

2015: +130k

2014: +260k

2013: +340k

2012: -650k

2011: -210k

2010: -380k

2009:+640k

2008: +220k

2007: -400k

 

For the minimum Sea ICe Area prediction, we can use prior years' melt out from July 1st onward to estimate how this tear will turn out because there hasn't been much of a trend in ice loss after 7/1....the big trend has been prior to 7/1. We have maybe seen a slight increase in melt from 7/1 since 2007, so I will weight those years more.

Below is a table of how 2022 would turn out if it followed previous years' melt out from 7/1 onward....

 

image.png.881f7655db1d54ec04000ae2a38e71a7.png

 

For example, if we used 1989's ice loss from here on out, we'd finish at 2.66 million sq km. 2016 had the highest meltout beyond 7/1 on record, and would produce a final SIA min of 2.55 million sq km if we followed that path in 2022. You'll note that the record year of 2012 is only like 4th or 5th most ice loss from 7/1 onward which means most of the damage was done prior to 7/1. We can pretty much rule out a new record this season based on this data. We'd need to obliterate the post 7/1 loss record set in 2016 to achieve it. A top 3 lowest min is probably out too.....likewise, a top 3 highest min in the post-2007 context is likely out as well....though another 2010 from here on out would achieve it. All other post-2007 years would fail, however.

 

All that said, the average ice loss from 7/1 onward in the post-2007 era is 4.09 million sq km which would produce a 2022 min of 2.98 million sq km (7.07 million minus 4.09 million). I'm going to stick very close to this number and go with a final minimum of 3 million sq km +/- 300k. I might hedge a little higher if the forecast was colder on the Beaufort/CAA side over the next week but they will continue to see mild weather so I will stick with 3 million.

 

Final extent prediction is a lot harder than area because extent relies a lot upon compaction/dispersion which is really hard to forecast. But that said, usually something in the 3 million sq km range for area will produce an extent min on NSIDC of around 4.5-4.8 million sq km. So I will go with 4.6 million +/- 500k....I have larger error bars on the extent. (side note: JAXA extent usually comes in around 200k lower than NSIDC extent after their algorithm update post-2013....so I will not be using Jaxa to verify this prediction. Only NSIDC daily extent)

Update and verification of prediction earlier this season:

On 9/20, the NSIDC extent had risen to 4.75 million sq km which puts it 130k above the minimum of 4.62 million sq km several days ago. It is pretty safe to call the minimum at 4.62 million sq km. This extent is 7th highest (or 9th lowest) since 2007. Both 2017 and 2018 finished at 4.63 million sq km.....barely higher than 2022.

Area continues to rise too now at 3.6 million sq km, but we reached the minimum on that 9 days ago at 3.2 million sq km. The 3.2 million sq km area minimum ranks 5th highest since 2007....only 2009, 2013, 2014, and 2018 were higher.  The reason area ranked higher than extent was that the ice pack was more compact this season than other years like 2021 and 2017 which had lower area numbers but higher extent minimum.

 

The predictions quoted above were for area to finish at 3.00 million sq km (+ or - 300k) and for extent to finish at 4.6 million sq km (+ or - 500k). Verification fell within these predictions (and almost exactly for extent), so I am glad to see that the meltponding continues to be a very accurate predictor of minimum extent/area.

 

I don't do predictions for volume, but PIOMAS volume minimum has likely been reached as well at 5039 cubic km.....which is the 10th lowest in the record. It is the highest minimum volume since 2015.

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  • 3 weeks later...

Great job from the statistical Arctic sea ice modeling team. The early June forecast was just a little on the low side but still good for such a long lead time. It corrected higher as the months went on. So another September average extent in the 4s. This has become the new normal since 2007 with 11 out of the last 16 years in this range.

2022….4.87

2021……4.92

2020……3.92

2019……4.32

2018…...4.71

2017……4.87

2016……4.72

2015…..4.63

2014…..5.28

2013…..5.35

2012…..3.60

2011……4.61

2010…..4.90

2009….5.36

2008….4.67

2007…..4.28

 

 

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