It’s been an interesting season for Arctic sea ice, and could become very interesting if current forecast weather patterns persist.

As we all know, the record holder for lowest area and extent is 2012, by some way. Before that it was 2007. In several recent years we’ve seen very low winter ice concentration and rapid melt in spring, but it’s slowed to a crawl later in the season as low pressure and cloud filled the Arctic basin.

2020 is different. Melt rates so far have been unspectacular by recent standards. Just chugging down slowly but surely. Most melt has been on the Siberian side of the Arctic. But despite that the current area and extend are at or close to record lows for the date (extent is lowest, area 4th lowest).

Here are the current charts for the year to date:

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However, a pattern is now setting up in the high Arctic that is brutal for sea ice: high pressure and strong sunlight over the central basin and Beaufort sea; warm air advection into the basin from a very hot Siberian landmass; and low pressure across Western Siberia / Scandinavia which tends to pump ice down through the Fran strait and out of the basin (cooling the seas and air in the North East Atlantic). This is the so called Arctic Dipole Anomaly pattern, and it was the main cause of the record melt in 2007 and 2012.

Here is the current extent and thickness of ice. The thickest stuff is in the Beaufort sea and, as usual, up against the North coast of Greenland and the Canadian Arctic archipelago. Ice is notably thin in the Eastern basin. Even with average melt the Northern sea route past Siberia should melt out this year. 

We should start seeing the results of the ADA in the next few days. Indeed we’ve already seen several days in a row of big area reductions over 100k km2. One to watch.

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https://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow_asiaeurope.gif

 

 

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So, on cue we just had a 200k km2 drop in sea ice area and sea ice extent per the NSIDC measure. Close to a record for 5 day average melt.

More like this to come next week I think.

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Another century drop in extent overnight means 2020 is now well in front on extent on the Jaxa satellite measure, and close to top with NSIDC (the two use different % concentration cutoffs to count extent, hence some difference. I expect the cliff to continue most of this week.

My links above seem not to work anymore so here's a snapshot of extent and concentration from NSIDC. The heavy loading in the Fram strait off East Greenland is clear to see. That ice is gone: on its way out of the basin.

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Thanks for starting an Arctic monitoring thread for the extraordinary period we're now in, Tim .

I've been reading around the ASI forum a lot in recent weeks. Some highlights from the past few days:

 

June was the 2nd warmest on record in the Arctic, behind 2005 and ahead of 2019 (yep, 2nd & 3rd set two years running). This despite weather patterns being not particularly unusual over the Arctic Ocean. Likely has a lot to do with the extreme Siberian heatwave, as some of that was within the Arctic Circle - including (only just!) the astonishing 38.0*C record on 16th June that's now been confirmed by the WMO.

 

NSDIC daily extents and losses since 27th. Long-term average is near -100 K per day, but these numbers are still relatively large:

Values in thousand square km.

2020-06-27  9,854
2020-06-28  9,723  -131
2020-06-29  9,575  -148
2020-06-30  9,445  -130
2020-07-01  9,262  -183
2020-07-02  9,142  -120
2020-07-03  8,942  -200
2020-07-04  8,807  -135

 

Meanwhile, area's been plummeting too, with 5-day trailing average losses of 199,000 sq. km yesterday and 212,000 sq. km today. Like with daily extent, the long-term average loss rate is around 100,000 per day.

Some Fram export is evident in buoy observations, while a large 'bite' of sea ice melt is advancing from the Laptev Sea into the Central Arctic Basin (CAB). A mixture of melt ponds and open waters.

Reportedly (according to 'Frivalousz21', who can be a bit melodramatic but tends to be so with good justification in my experience, there's been a large swathe of fog affecting the CAB lately, which has masked some melt ponds beneath. That implies that the area losses registering on satellite could have been even larger than they have (melt ponds are incorrectly registered as open water, but do indicate strong melting so are still bad news)!

Considering that this fog was preceded by a blast of air from the toasty lands of Siberia, it's possible that this fog has been at above-zero temps. If so, that will be melting sea ice unusually fast; water molecules transfer energy more efficiently than air molecules (water has a higher specific heat capacity).

The daily 'High Arctic' region albedo warming potential has hit a record high.

Topping last year and leaving 2012 in the dust (for this point in time).

The cumulative WP will be rising fast, having slumped a bit in June after storming out of the gates in May. Not seen an update on that in the past fortnight.

 

Overall, alarm bells are ringing. Mid-June to mid-July is the time of year when high pressure over the Arctic has the highest potential negative impact on the sea ice - and it looks like 2020 is realising a lot of that potential.

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After another big melt day both area and extent are lowest on record for the day. Here’s the latest tumble in area. Remains to be seen if it’s sustainable or a blip. 

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Do we know if there's any sort of feedback loop regarding ice melt? I've heard the theory that [in a very brief nutshell] less ice leads to the increased likelihood of the formation of high pressure over the Arctic. That would presumably create some sort of loop.

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Do we know if there's any sort of feedback loop regarding ice melt? I've heard the theory that [in a very brief nutshell] less ice leads to the increased likelihood of the formation of high pressure over the Arctic. That would presumably create some sort of loop.

I think what you refer to is actually a negitive feedback. Reduced sea ice encourages low pressure during summer months which retards ice melt. This is why 2013 saw a big rebound after 2012, 2008 after 2007 e.c.t.

However there are also positive feedbacks at work including albedo. Reduced sea ice thickness = lower albedo in summer = more melt and so on.

Overall the positive feedbacks are more important than the negative ones, but the negitive ones can still give interesting effects.

 

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The 12z ECM keeps the high at over 1030 mb peak right out to day 9, with a gradual drift across the East Siberian Sea from day 7.

GFS has similar ideas, though not quite so dramatic.

It's nasty for the central basin and Asia-side peripheral seas generally, but brings yet more relatively kind conditions to Beaufort, which is starting to look likely to be the most healthy of the seas during Aug-Sep, unless there's a monumental shift to warm air movement across there and/or a persistent high overhead that establishes by early August (while solar insolation is still high enough to cause trouble). 

The Atlantic side gradually sees an increasingly maritime flow regime, which could be difficult to, ahem, weather for the areas of ice from Svalbard to Barents.

We could have a peculiar shape to the sea ice by late August 2020. Well below normal coverage generally on the Atlantic and Asian sides, but above normal in the eastern half of the Pacific side i.e. Beaufort.

There's a big problem with having most of the eggs in that sea, though. It's more vulnerable to late season melt due not only to its greater distance from the North Pole, but also the potential for ice to leave that sea via numerous channels that meander across the Canadian Arctic Archipelago. This is known to some as the 'garlic press'. It's not a reliable event, for it depends on to what extent areas of thicker ice, ('ice bridges') blocking the channels, give way under melting pressure and water motion. Some years, hardly any give out, yet in some others, most or all of them break.

Thankfully, the CAA isn't looking to see any more heatwave conditions within the next week or so. The one it recently had for a fortnight or so did a lot of damage, though, with volume dropping off a cliff, so I have my concerns about those channels. It might only take a week of warm conditions sometime within the next two months to bring about a lot of bridge breaks.

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Another couple of days of very substantial losses (on one day getting close to 200k km2 per day in extent), and the high pressure and sunshine that the Arctic basin nicked from us at the end of spring it seem to want to keep. Look at below - almost cloudless over huge swathes of the basin.

 

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https://www.aer.com/science-research/climate-weather/arctic-oscillation/ 

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Thanks for posting that link Tim. That's a fascinating read. I was especially interested in the split jet stream theory. I certainly agree that our weather gets stuck in a rut far more easily than it did in the late 20th century, so that makes sense. The weather outlook looks better for late July according to this post, but I think I'll believe it when the fax charts show it! Also the August outlook sounds more positive for us, although the chart that is displayed does not really show this for northern Europe.

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Bump; don’t want to lose this thread.

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Another century drop means 2020 extent is currently more than 600,000 sq km below 2019 and more than 800,000 sq km below 2012 - the year with lowest September minimum. How low extent goes from now depends on several factors including how much extra energy is already in the system - eg how much bottom melt we get even if a colder surface pattern develops - and in what way the weather pattern changes when the persistent anticyclone disappears. Worst pattern for ice retention is probably a strong cyclone with heat import and strong winds. Best pattern for ice retention probably slack low pressure - ie cool but not windy. High pressure in August is less damaging than earlier in the season.

https://twitter.com/peacockreports/status/1285530999695331328

This ranks highly in my 'patterns we don't want to be seeing' list.

FYI - the top-ranked pattern as we move into late July and then August is one of high pressure over the Canada-ward half of the Arctic and low pressure on the other - the classic 'Arctic dipole'. 

This is a change from mid-June to mid-July, for which it's centrally based high pressure... such as we've just had for about half that period.

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