Things just keep getting worse. After this year's trend line went well below all others last month, I was hoping January would bring some relief, some cold weather. The weather was cold, colder than November and December, but evidently not cold enough for some seriously anomalous ice accretion. And so the gap has widened.
According to the PIOMAS model, in the past 10 years, only twice before was there a January in which less than 3000 km3 of volume was added to the sea ice pack: in 2007 and last year. So, these are the only two years that didn't see the gap get wider. All the other years did.
2017 is currently 1571 km3 below the previous record lowest number for January 31st, which occurred in 2013 (the year following record smashing 2012). That's almost 10% lower.
Here's how the differences with previous years have evolved from last month:
And here's Wipneus' version, clearly showing the gap widening:
And, of course, this is also reflected on the Death Spiral graph. Here's a version made by Andy Lee Robinson (the guy from the ice cube video, and I mean a real ice cube, not the gangsta rapper), red line is for January and you'll notice that it's as low as or lower than nearly all the Septembers of the 80s:
As for the PIOMAS sea ice volume anomaly graph, the trend line has dipped well into two standard deviation territory again:
With both extent and volume still at record low levels, nothing much has changed on the PIJAMAS thickness graph (a crude calculation of PIOMAS volume numbers divided by total JAXA sea ice extent), with the current trend line still lowest on record as of January 31st. In fact, the gap between 2017 and 2013 has widened from 4 to almost 8 cm:
The Polar Science Center thickness plot is showing the exact same ting:
So, what caused the gap to widen between 2017 and previous record holder 2013? I've downloaded surface air temperature (SAT) and sea level pressure (SLP) maps from the ESRL/PSD daily mean composites website for January 2013 and 2017:
Temperature-wise the differences aren't all that great, although it was cold in the southern part of the Canadian Arctic Archipelago in 2013, whereas in 2017 the anomaly is all over the Arctic. The real difference is in sea level pressure. January 2013 was dominated by high pressure, which means skies were clear during the long polar night, and so there was a lot of outgoing longwave radiation, with no clouds to bounce some of it back to the surface. And very little snowfall to insulate the ice and slow down the thickening process.
There also was a lot of clockwise movement of ice, with leads opening up and refreezing again (remember the huge cracking event we saw later in February 2013?). This atmospheric set-up causes some ice to be transported through Fram Strait, but at the same time the Transpolar Drift Stream pushes the ice towards Greenland and the CAA, where it can then thicken up and turn into the multi-year ice that is keeping the Arctic sea ice pack alive (for now).
This year there was none of that, as the opposite happened: Low pressure dominating, brought in by the multiple Atlantic storms that battered the Arctic (the strongest of which I described in a recent blog post). These storms increased precipitation, creating an insulating layer of snow atop the ice. They brought in clouds that bounce the outgoing radiation back down again. And finally, the way the cyclones swirled towards the Kara Sea, meant that the anti-clockwise winds pushed out large amounts of (multi-year) ice through Fram Strait, as well as through the area between Svalbard and Franz Josef Land, into the North Atlantic, where most of it melted immediately.
In short, January 2017 was pretty much disastrous for the sea ice. There's just two months of freezing left, and after that we can only pray for a repeat of 2013, the first of two post-2012 rebound years, where clouds and cold temperatures prevented an Arctic sea ice catastrophe.
I'll end with a graph that has been doing the rounds lately. It was introduced by the late Andrew Slater and has now been adopted by several others (such as Zack Labe, who puts out a lot of good stuff via Twitter). It shows cumulative Freezing Degree Days, also known as freezing power, based on temperature data north of 80° latitude from DMI. This one is made and updated by ASIF commenter Nico Sun, aka Tealight, on his CryosphereComputing website: