Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:
A new year, a new trend line, and if you watch the above graph closely, you'll see how it dips right under the 2013 trend line at the end of January. This means that 2018 now has the second lowest sea ice volume on record, according to the PIOMAS model. A monthly total of 3005 km3 was well below the 2007-2017 average of 3195 km3, which means 2018 also extended its lead over most other years. Last year, however, January volume was 50 km3 lower still and so that gap has grown slightly bigger again. Given how volume fared during the first few months of 2017, it doesn't look like that 1407 km3 gap is going to be bridged any time soon.
Here's how the differences with previous years have evolved from last month:
Wipneus' version of the PIOMAS graph more clearly shows how the 2017 trend line (light red) goes off even further on a tangent:
The trend line on the PIOMAS sea ice volume anomaly graph bends down again:
Nothing much has changed on the PIJAMAS average thickness graph (crudely calculated by dividing PIOMAS numbers with JAXA sea ice extent numbers):
The same goes for the thickness graph from the Polar Science Centre:
February started just one week ago, but has already been eventful so far. A powerful storm was hurled into the Arctic via the North Atlantic, eventually bottoming out at 952 hPa. The forecast hinted at possibly above freezing temperatures near the North Pole (as happened in December 2015), and even though it didn't pan out that way, a lot of heat was advected toward the Arctic's heart:
At the same time the ice edge was pushed back (which is still ongoing), as can be seen on this animation of Uni Hamburg AMSR2 sea ice concentration maps for the past 5 days, as provided by Jim Hunt on his Great White Con blog (he provides lots more info, check it out):
Of course, all these strong winds are preventing ice - some of it thick - from escaping the Arctic via Fram. As the latest NSIDC monthly summary has it:
A single storm event can lead to significant redistribution of sea ice mass through ridging and new leads. As part of the Norwegian Young Sea ICE (N-ICE2015) expedition, colleagues at the Norwegian Polar Institute made detailed sea ice thickness and ice drift observations before and after a storm in an area north of Svalbard (Figure 5). Results showed that about 1.3 percent of the level sea ice volume was pressed together into ridges. Combined with new ice formation in leads, the overall ice volume increased by 0.5 percent.
At the same time, Atlantic heat is accompanied by moisture, which is deposited as snow on the ice pack. We've seen what effect last winter's train of Atlantic storms may have had during the start of the melting season, when possibly large amounts of snow on the ice managed to deflect early solar radiation that determines the timing and magnitude of melt pond formation, which in turn can play a significant role with regards to melting momentum.
Nevertheless, these short-term effects may be just enough to nudge Global Sea Ice Extent to yet another record low minimum (although Antarctic sea ice also has a say in this, of course):
Ah, I fondly remember the days when climate risk deniers would argue everything was normal 'because global sea ice'. It is indeed normal, as in SNAFU. ;-)
As for snow, according to the Rutgers University Global Snow Lab, the Northern Hemisphere snow cover anomaly was barely positive and a lot lower than most years of the previous decade:
I'm not sure how PIOMAS will handle this storm (which may be followed by more, given the current atmospheric set-up using Greenland as a flywheel), but if extent stays as low as it currently is (lowest on record in several data sets) and the Arctic stays as mild as it has been so far, relatively speaking, there's a very good chance 2018 sea ice volume will still be second lowest come next month.
To close off, here's my NCEP reanalysis temperature graph (courtesy of ESRL, Physical Sciences Division). A record non-cold December was followed by the second 'mildest' January on record. This, again, mainly had to do with temperatures in the Pacific sector (also second lowest), while temps in the Atlantic, Siberian and Canadian sectors were 6th, 7th and 5th lowest on record respectively.
If you want to know what's going in the Arctic in near real-time, go to the 2017/2018 freezing season thread on the Arctic Sea Ice Forum. Lots of great stuff.
Rendez-vous next month, same time, same place.