PIOMAS November 2018
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:
October has seen a continuation of the trend that set in right after the September minimum (see last month’s update), where 2018 went from 6th lowest at the minimum to 5th lowest at the end of the September, and now it’s 4th at the end of October, practically on a par with 2011. The increase of 2115 km3, well below the 2367 km3 average, was actually 3rd lowest in the 2007-2018 record, with only 2007 and 2016 having an even lower increase (1637 and 1648 km3 respectively). That means that 2018 has crept closer to the years below it, and moved away further from the years above it, overtaking 2017 for the first time this year.
Here’s how the differences with previous years have evolved from last month:
Wipneus’ version of the PIOMAS graph shows how this year’s trend line blocks out that of 2011, that’s how close together they have been for a couple of weeks now:
The anomaly trend line on the PIOMAS volume anomaly graph is smack on the linear trend line, after having briefly dipped below it (which I wasn’t expecting until next summer):
On both average thickness graphs, my crude calculation (by dividing PIOMAS volume numbers with JAXA extent) and the Polar Science Centre version, the trend line has dropped to third lowest now, probably indicating that extent grew a bit faster than volume:
The relatively slow volume increase during October almost certainly had to do with anomalously high temperatures (see this blog post from last month). The following temperature anomaly maps come from this article on Meereisportal, which also presents some great buoy temperature graphs based on data that was collected for the international science project NABOS (Nansen and Amundsen Basins Observational System):
The map on the right shows the massive temperature excursions over the Central Arctic and Siberian mainland, while Greenland and Canada are colder than average. This resulted in a second warmest Arctic on record, as shown on Zack Labe‘s excellent monthly air temperature ranks (north of 70°):
I use the same data, but from 65N to the pole, and also split the data up into four quadrants to get more regional info on surface air temperature. Here too we see that for the Arctic as a whole October 2018 was the second warmest on record. This was mainly due to a new record high for the Siberian quadrant (a stunning 1.5° C higher than the previous record set in 2007), but the second highest temperature for the Pacific helped as well. The temps in the Atlantic and especially Canadian quadrants were low enough to prevent a new record high for the Arctic as a whole:
Nevertheless, this freezing season still has the lowest amount of Freezing Degree Days so far, as shown on commenter Tealight‘s graph (this is for north of 80°, based on the DMI 80N graph), still managing to keep up with crazy 2016:
One last goodie provided by the good people of the Polar Science Center, a comparison of the PIOMAS and CryoSat-2 thickness anomaly maps for October. I’ve combined the two maps and created this animation:
They are in reasonably good agreement, and more importantly, they show the effect of the Western Arctic being spared the worst this summer (where most of the red is). This ice will most probably be thicker next melting season, and if it gets transported westwards due to a strong Beaufort Gyre this winter, it might get in a position where it could help protect the ice further towards the pole by taking longer to melt out. Of course, the ice elsewhere is thinner compared to the 2011-2017 average. PIOMAS volume is 3rd/4th lowest on record for a reason.
For now, the start of winter has been similar to the past couple of years, with volume growing relatively slowly and temperatures being anomalously high. But we have almost 6 months left to go before we can say anything meaningful about what this winter will have meant for Arctic sea ice.
PS Some people, including myself, have trouble logging in. I’ve taken this up with Typepad, and hopefully things will soon get fixed.