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Arctic Sea Ice Extent, Area, and Volume


ORH_wxman
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  • 3 weeks later...
1 hour ago, cny rider said:

Can you explain how that could happen in February?
Thanks.

 

We've seen a pretty substantial decline in the NSIDC sea ice extent the last few days.

The last time the winter max occurred in February was 2015. So there is recent precedent.

 

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2 hours ago, bdgwx said:

We've seen a pretty substantial decline in the NSIDC sea ice extent the last few days.

The last time the winter max occurred in February was 2015. So there is recent precedent.

 

No expert, but the data at :  https://cryospherecomputing.tk/NRT2.html  show some sort of glitch since Feb 19th. Is there a better source?

Separately, I do agree that the recent ice trends have been suggestive of an early peak, but we do need a better confirm.

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44 minutes ago, etudiant said:

No expert, but the data at :  https://cryospherecomputing.tk/NRT2.html  show some sort of glitch since Feb 19th. Is there a better source?

Separately, I do agree that the recent ice trends have been suggestive of an early peak, but we do need a better confirm.

I usually just go to NSIDC directly. https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

I did see that glitch on that site earlier today. I was assuming the glitch was isolated to that site. The data on the NSIDC site looks good.

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11 hours ago, bdgwx said:

I usually just go to NSIDC directly. https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

I did see that glitch on that site earlier today. I was assuming the glitch was isolated to that site. The data on the NSIDC site looks good.

The data on that link also stop at Feb 19th and the scan map shows that one sector was unscanned, which was the cause of the sudden downturn.

Maybe a data processing issue with the satellite or the ground station?

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2 hours ago, etudiant said:

The data on that link also stop at Feb 19th and the scan map shows that one sector was unscanned, which was the cause of the sudden downturn.

Maybe a data processing issue with the satellite or the ground station?

Oh...you're right. Between both Chrome and Edge cutting off support for ftp and having to switch to WinSCP to download the data I didn't even notice that it hadn't updated.

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Here is the NSIDC's update regarding the sea ice data problems.

Quote

NSIDC continues to investigate errors in our sea ice processing, and we are upgrading software to address the errors. Daily Sea Ice Index/Arctic Sea Ice News and Analysis values after February 19 are erroneous. We will post new data as soon as the software upgrades are implemented.

https://nsidc.org/arcticseaicenews/2021/03/nsidc-continues-to-investigate-sea-ice-processing-errors/

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8 hours ago, StormchaserChuck! said:

my theory is that we are few years behind in arctic ice melt. 

So what is your implication, that we will see rising arctic ice levels from here on out?

 

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  • 2 weeks later...

We've seen 3 local peaks. One on Feb 15th, one on Mar 6, and the most recent on Mar 12 with a 5D average of 14.75 per NSIDC extent. We cannot eliminate the possibility of a higher max (the 2012 max occurred on Mar 20), but with each passing day the probability decreases. It looks to me like the melt season is going to start lower than it did last year.

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  • 2 weeks later...

https://nsidc.org/arcticseaicenews/2021/03/arctic-sea-ice-reaches-uneventful-maximum/

"On March 21, 2021, Arctic sea ice likely reached its maximum extent for the year, at 14.77 million square kilometers (5.70 million square miles), tying for the seventh lowest extent in the satellite record with 2007. This year’s maximum extent is 870,000 square kilometers (336,000 square miles) below the 1981 to 2010 average maximum of 15.64 million square kilometers (6.04 million square miles) and 360,000 square kilometers (139,000 square miles) above the lowest maximum of 14.41 million square kilometers (5.56 million square miles) set on March 7, 2017. Prior to 2019, the four lowest maximum extents occurred from 2015 to 2018."

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So this is interesting. Fram Strait export picking up with such an anomalous high pressure system with a countering LP just east. Yes 1089mb high forecasted over Greenland in a little over 3 days. We have had such large high pressure systems this year, earlier around Mongolia if I remember correctly back in December I dont believe broke the record there but was awfully close.

Impressive stuff this year. I worry about the ice on the Atlantic front to near the north pole especially this year with how low thickness values are to the norm.

gfs_z500_mslp_nhem_17.png

AMSR2_SIT_Last_month.gif

 

Edit it actually beat the world record

https://www.independent.co.uk/news/uk/home-news/world-record-high-air-pressure-mongolia-b1780381.html

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Thats pretty crazy to me. I dont think I have seen pressures higher than maybe mid 1060's mb around Greenland so if even the 1070-1080mb range verifies this may very well be a record, unfortunately my search has come up empty on the highest pressure reading from a station on Greenland's ice sheet unless others may know.

I just noticed the map I posted of ice thickness ended at the last day of February so here is hycoms depiction of the last 30 days fairly similar to AMSR where the highest values are but there are some differences that stick out such along the CAA and siberian sea region so it will be interesting to see which is closest to reality. Still both show issues on the Atlantic front to the north pole so they both seem to agree at least on that front.

 

I guess the one positive, if you really wanna call it that, is the lack of multi year thick ice what is left of it isn't being exported into the Atlantic to melt off. Ill have to see if I can find a multi year ice gif to show where we have the remaining portions of it and what is rather new thin ice. 

arcticictn_nowcast_anim30d.gif

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I could see it making a run at the low 1060's. :But I'll be extremely surprised if it hits 1070mb. There is going to be a pretty steep pressure gradient either way. The Euro actually shows slightly higher sustained winds than does the GFS even though it is much weaker with the anti-cyclone. It certainly looks like Fram export will be in high gear shortly.

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Little update I believe we measured the greenland high around 1065mb give or take a few mbs just south over the ocean had a slp of 1040s so seems reasonable with the potential of higher over the ice sheet. Always hard to know with a large portion of that region being 10-13k feet above sea level, so you know extrapolation. Still have quite the fram export event taking place as the low moves into the Central Arctic regions. Looks as though there may be a day or two of slowing down on export but man it looks like it picks right back up in mid to long range. Really hope this is not a sign of a major ice depletion situation.

With such strong export Ice is reaching Iceland, this happens from time to time but I dont recall it being the case this time of year. Again maybe the one nice thing is we aren't exporting some of the multi year ice that is left, what little there still is.

Very worrisome of what may come this summer.

arcticicespddrf_nowcast_anim30d.gif

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  • 1 month later...

Two theories have emerged as to why the September 2012 record minimum has held on for so long.  There  is probably a piece of truth to both of them. But it’s interesting how every other time of the year has set new minimum records since 2012. So one of these years we’ll eventually surpass the record. Last year came the closest.

https://climate.nasa.gov/news/2817/with-thick-ice-gone-arctic-sea-ice-changes-more-slowly/

With thick ice gone, Arctic sea ice changes more slowly

Kwok's research, published today in the journal Environmental Research Letters, combined decades of declassified U.S. Navy submarine measurements with more recent data from four satellites to create the 60-year record of changes in Arctic sea ice thickness. He found that since 1958, Arctic ice cover has lost about two-thirds of its thickness, as averaged across the Arctic at the end of summer. Older ice has shrunk in area by almost 800,000 square miles (more than 2 million square kilometers). Today, 70 percent of the ice cover consists of ice that forms and melts within a single year, which scientists call seasonal ice.

Sea ice of any age is frozen ocean water. However, as sea ice survives through several melt seasons, its characteristics change. Multiyear ice is thicker, stronger and rougher than seasonal ice. It is much less salty than seasonal ice; Arctic explorers used it as drinking water. Satellite sensors observe enough of these differences that scientists can use spaceborne data to distinguish between the two types of ice.

Thinner, weaker seasonal ice is innately more vulnerable to weather than thick, multiyear ice. It can be pushed around more easily by wind, as happened in the summer of 2013. During that time, prevailing winds piled up the ice cover against coastlines, which made the ice cover thicker for months.

The ice's vulnerability may also be demonstrated by the increased variation in Arctic sea ice thickness and extent from year to year over the last decade. In the past, sea ice rarely melted in the Arctic Ocean. Each year, some multiyear ice flowed out of the ocean into the East Greenland Sea and melted there, and some ice grew thick enough to survive the melt season and become multiyear ice. As air temperatures in the polar regions have warmed in recent decades, however, large amounts of multiyear ice now melt within the Arctic Ocean itself. Far less seasonal ice now thickens enough over the winter to survive the summer. As a result, not only is there less ice overall, but the proportions of multiyear ice to seasonal ice have also changed in favor of the young ice.

Seasonal ice now grows to a depth of about six feet (two meters) in winter, and most of it melts in summer. That basic pattern is likely to continue, Kwok said. "The thickness and coverage in the Arctic are now dominated by the growth, melting and deformation of seasonal ice."

The increase in seasonal ice also means record-breaking changes in ice cover such as those of the 1990s and 2000s are likely to be less common, Kwok noted. In fact, there has not been a new record sea ice minimum since 2012, despite years of warm weather in the Arctic. "We've lost so much of the thick ice that changes in thickness are going to be slower due to the different behavior of this ice type," Kwok said.

Kwok used data from U.S. Navy submarine sonars from 1958 to 2000; satellite altimeters on NASA's ICESat and the European CryoSat-2, which span from 2003 to 2018; and scatterometer measurements from NASA's QuikSCAT and the European ASCAT from 1999 to 2017.


https://iopscience.iop.org/article/10.1088/1748-9326/abc047

 

Why has no new record-minimum Arctic sea-ice extent occurred since September 2012?

4. Discussion and conclusions

The behavior of Arctic sea ice during recent years has perplexed the scientific community. The ice extent has attained or flirted with new record lows during winter and spring months every year since 2012, raising the specter of hitting a new minimum in September. Instead, however, the ice-loss trajectory took a sharp turn in August or early September (except in 2020), averting a broken record. Responsible for the cessation was the formation of low pressure over the region, which brings clouds, reduced insolation, and winds conducive for expanding the ice cover. The consistency of this occurrence begs the question: why is it happening?

Here we offer evidence that the dramatic negative trend in spring snow cover over high-latitude land areas—one of the most conspicuous indications of anthropogenic climate change—may be an important contributor to this behavior. The early loss of snow cover creates a belt of positive temperature anomalies that distorts the typically monotonic poleward temperature gradient by creating an additional peak. Through the thermal wind relationship, a split jet is more likely to form, favoring conditions that trap and amplify Rossby waves that have been implicated in causing extreme summer weather events over northern hemisphere continents.

The second most prominent atmospheric state (PC2) during summer is associated with similar split-jet conditions, along with continental heatwaves in Asia, Scandinavia, northern North America, and ocean heatwaves in the North Atlantic and Pacific Oceans. This pattern is also significantly correlated with strong westerly winds over the Arctic during summer, creating cyclonic conditions that favor cloudiness and reduced transport of sea ice southward through the Fram Strait into the Greenland Sea. Moreover, since 2012, this second PC has exhibited several of its highest values in the record back to 1979, while a stretch of 6 yr (2007–2012) with its lowest values was accompanied by rapid declines in sea-ice extent.

We hypothesize that these observations are connected, and while we cannot establish cause-and-effect and not every year will follow this chain of linkages, a negative feedback on the decline in sea-ice extent initiated by early spring snow-melt may provide a plausible explanation for the recent puzzling behavior of the late-summer sea-ice behavior. We note that the summers of 2019 and 2020, characterized by high values of PC1 and low values of PC2 (in contrast to most years since 2012), recorded near-record-low minimum sea-ice extent during September (Richter-Menge et al 2019; http://nsidc.org/arcticseaicenews/), suggesting that these atmospheric patterns during JJA may provide some predictive information for the annual sea-ice minimum. It should be noted that this application of EOF analysis reveals statistical relationships only, and future research will require targeted modeling experiments to verify causal mechanisms. These experiments might include comparisons of atmospheric patterns under conditions of climatological snow cover and soil moisture versus those projected for the late 21st century under continued greenhouse gas forcing. A further research opportunity could apply these atmospheric patterns to test the ability of climate models to simulate observed relationships between rates of sea-ice loss, large-scale circulation regimes, and extreme summer weather in mid-latitudes.

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