Wednesday, 25 May 2016

Where is the low extent coming from?

Using Cryosphere Today regions, where is the low extent at present coming from?



I have used Wipneus's calculation of AMSR2 extent because of the F17 sensor failure. As of 3 May 2016 NSIDC stated that their expectation was 2 months or more for a resumption of sea ice data NSIDC-0081. This means the season might largely be over before I can resume normal analysis using anomalies from a long term baseline common to both ice and atmospheric data.

With AMSR2 only 2013 to 2016 are available, so I have calculated extent on  day 145 (24 May in 2016) as the difference from the 2013 to 2015 average for each region. This is then expressed as the percentage of the overall extent difference from the same period.

Years that are the lowest regional extent for 2013 to 2016 are marked with a red cross.


Half of the regions are at record low extent for day 145.

The vast majority of the loss (46%) is due to the Beaufort and Barents Seas. Beaufort is due to wind action, which may now be being amplified by ice albedo feedback, Barents continues the long term trend of recession in this region, which may be due to warming of the North Atlantic.

Only the East Siberian Sea, Laptev Sea, and the Canadian Arctic Archipelago are above the average for recent years.

The ice edge has entered the Central Arctic region, this is due to recession poleward of Svalbard.

Conditions are set up for a very low September extent, 2016 might challenge 2012 with the right summer weather. However significant ice may persist well into July in the seas bordering the Eurasian coast.

2 comments:

Abbott IsGone said...

http://www.esa.int/spaceinimages/Images/2013/09/Variations_in_spring_ice_thickness

Interesting how 2012 has a line of yellow right through where the multi-year sea ice hangs out on the back of the CAA/Greenland area.

2011 seems to share this phenomenon but a lot further away from the coast presumably allowing the thicker ice to maintain some structural integrity yet it too must have an effect,... it's possible these have both delivered long term effects.

2013 doesn't show it at all. I've only looked at these 3 years but it might be worth looking at more.

Anyway, my question is: is the above the actions of the Beafort Gyre?

If so that does not bode well as all the blogs have been talking about is the activity of this years Beaufort Sea Gyre. Just thought it was interesting to see how divide and conquer seems to be the way it works: the position where the divsion is taking place obviously has an effect and, more importantly, needs explanation.

Chris Reynolds said...

AiG,

I think it's not just the Beaufort gyre, but also the survival of ice in the summer.

Isn't the yellow just the rise up to the thicker ice? I wonder how the slope changes? Would the transpolar drift affect it - a strong transpolar drift leads to a steeper rise in thickness, weaker TP drift leads to a less steep slope and greater area of ice shown as yellow.