Continental Asia has a great assortment of anomalies to work with today. We’re going to investigate the value of the more interesting ones by focusing on just three variables, each of which can create large differences at this time of year. Sometimes they add up and sometimes cancel each other out. The three are total precipitable water (TPW), snow cover and sea ice, all of them mapped in their current state. I have added a map of snow depth because sometimes it will add important clarity to otherwise ambiguous images of snow cover alone. All we are missing is accurate information about relevant baseline averages for these factors, but they can all be reasonably well estimated. (Thankfully, this is a matter of no concern when it comes to temperature anomalies.) Cloud cover and precipitation are not included on this list of factors because I think the albedo effect of cloud cover does not make much difference this far north at this time of year. I’ll mainly be showing the map images with only a few basic comments, and urge you to spend some time on your own making comparisons.
On this map we are seeing two large hotspots in the Arctic Ocean that require special attention, another in the area where southeast Siberia meets northeast China, and the one in the Himalaya mountain area north of India. The very large region of cold anomalies can only have one explanation, a widespread relative shortage of TPW. Such an assumption will be easy to accept when you see all the gray shading on this next map. Remember that gray shading, maybe even on the dark side, is always just plain normal at this time of year for adjoining elevated locations and for the entire region farther to the north.
Now we’ll look at the Sea Ice/Snow Cover map. The absence of sea ice is a major factor for temperatures in several spots that are not especially large in size. A shortage or absence of snow cover is a factor applicable to an area of unusual size this year, possibly greater than the total area where snow has fallen and stayed in place. I think a normal year from a few decades back would have snow fully covering almost all of the ground that is presently dotted with little more than a few random freckles. Snow is an effective insulator, and holding back an extra 5C or so from radiation that could come out of the ground should not be surprising. Almost the entire Himalayan range may be affected in this way plus many parts of a wide swath from the mountains up to and including the southeastern corner of Siberia. Many of the warm anomalies in that region cannot be attributed to anything else when TPW readings are as low as what we’re seeing.
The Snow Depth map is especially useful for highlighting reasons for some of the smaller and relatively isolated warm anomalies that appear in numerous locations. Also, this map will always help in making judgments about relative importance whenever snow cover images of the thinner sort are showing.
The two major anomalies in the Arctic Ocean both display sea ice shortages plus high relative values of TPW. You may want to use magnification to pick out all the details of shapes and shadings. The eastern anomaly has a TPW reading no higher than 3kg, which is quite sufficient for additional warming of around 20C over normal. The actual temperature for this spot today on the Windy site is -16C, while a comparable area not far away is reporting -42C and lower. That area has a TPW reading of less than 1kg, probably closer to 500 grams. Both oceanic anomalies reflect the tail ends of high-altitude PW streams that have traveled thousands of miles from their sources, just like the many others we have watched in recent months but not quite as potent.
Carl