The thickness maps produced by the Naval Research Lab have switched to a new “product”, which makes the sea-ice in the central arctic look thinner. (Old product, October 17, to left; New product, October 21, to right.)
I’ll skip my usual tirade about how these “improvements” always seem to make the ice look thinner, except to say that, just eyeballing the maps, it looks like the sea-ice became three feet thinner overnight. However I will confess to being irked over how this change makes it very difficult to compare the conditions this year with last year’s.
Below is the last comparison I will be able to make, using old-style maps. 2016 is to the left and 2017 to the right.
Three things jump out at me. First, the Laptev Sea has been quicker to skim over with ice this autumn, which tends to suggest the East Siberian cold-pool means business this year. As Siberia tends to be the biggest contributor to nasty cold, watch for which direction the cold air aims. For me in the USA a cross-polar-flow or a flow across Bering Strait tends to be worst. For Europe, east winds bring the cruelty of Mordor. For China, winds straight from the north are cruelest. Best for all concerned is when Siberia drains out into the Pacific, though that may cool waters and be a case of delaying the inevitable.
Second, the waters north of Alaska are slower to freeze this fall, which may extend the delightful autumn parts of North America are having, to the south (though I suppose northern California is yearning for winter rains, after their wild fires.)
Third, a wrong-way flow in Fram Strait has prevented sea-ice from coming down the east coast of Greenland. This actually keeps sea-ice up in the central arctic, but does tend to make the “extent” graph look lower. (The long-range suggests the south winds in Fram Srait will change to north winds, and the flow will resume.) In any case, “extent” is well above last year:
Apparently, though the NRL maps have the sea-ice abruptly three feet thinner, the extent is greater. (I wonder if NRL realizes that this “correction” of their maps is an admission that their previous maps were seriously flawed. If so, someone should be so kind as to pat the back of my hand and apologize, for I sure did take some heat when I very politely suggested some flaws were visible, when I compared the view seen by satellites with the view seen by lying eyes through floating arctic cameras. The only problem is that lying eyes didn’t see ice thinner, but rather more widespread, and growing at times satellites suggested it was melting.) (Does this explain why they have cut the funding for cameras?)
Things are quiet at the moment, up in the arctic. The big high-pressure towards Siberia has weakened, and the flow it brought up through Fram Strait has fueled a weak version of “Ralph”, (the low pressure that has predominated for over a year). The above-normal temperatures that bisected the Pole are now chilling in the growing dark. Without new streams of mild air from the south the Pole simply has to get colder, with no sunshine.
Though things are currently quiet, we are actually midst a whiplash of sorts, as the Pacific cools. Over at his blog at Weatherbell (week free trial available) Joe Bastardi produced a clear comparison of how the sea-surface anomalies have changed, from above-normal to below-normal. 2015 Super-El-Nino to left; 2017 La Nina to right.)
Notice it is not merely cooler off Peru, but also off west Australia and even to a degree off southwest South Africa. Usually this is indicative of east-to-west winds increasing. Notice how the warmer water is pushed to east Australia. (For the moment I’m ignoring other factors, which in the past I have called the “bathtub-slosh” and the “toothpaste squeeze”.)
Often a strong El Nino is followed by a strong La Nina, and the fact this didn’t occur after the 2015 Super-El-Nino demanded some sort of explanation. The most obvious difference in the current situation was, in my eyes, the “Quiet Sun.” To me it seemed possible that less energy from the sun might mean there was less energy for the east-to-west winds. Therefore the La-Nina responce to the strong El Nino was held in check, though the components (which we don’t understand all that well) were likely all in place and champing at the bit. All it took was for the sun to get a bit “noisy” and the La Nina was unleashed. But now the sun is getting quiet again. After a series of spotless days we are seeing the sunspots that have rotated all the away around the sun are returning to view diminished.
A lot of “ifs” are involved. “If” the sun remains quiet, will the La Nina lose its power? “If” the La Nina wimps out, will the tropics warm towards an El Nino? And so on. Likely it is a good time to avoid making predictions, and better to sit back and study.
In the short term, it does seem things are moving in a cooler direction. It takes a while for such “lagged” effects to reach the Pole, but I am expecting to see short-term changes reach the north after the first half of winter, and foolishly stated the date we’d see the change (likely to a zonal flow and very cold Pole, with fewer arctic outbreaks) would be February 13. (That gives me time to pack and leave town if I’m wrong.)