Weather Break -- Winter in Siberia

This is a transcript of today's episode of the Weather Break radio show. The episode was written by Dr. Jon Schrage.

Meteorologists define “winter” as the three month period from December through February. So far, the winter of 2007-2008 has been quite warm across most of the continental United States. Sure, there have been some bitterly cold days in Nebraska and South Dakota (especially right around New Years), but the warm days have more than made up for it. Right now, most of Nebraska is running about 2°F above normal for the winter, with South Dakota being more like three to three and a half degrees above normal. Nationwide, only the state of Nevada is running below normal, with parts of Montana and the Ohio Valley averaging about 5°F above normal so far this winter.

Actually, temperature have been running a few degrees above normal in Siberia, too, although that’s probably not particularly comforting to a place where the average air temperature in the winter is about forty degrees below zero. Siberia, of course, is the vast, largely unpopulated region that makes up about three quarters of the area of Russia. It’s larger than the continental United States, and it makes up most of northeastern Asia.

I looked up some recent weather observations from stations in Siberia. On the morning of January 10, 2008, the weather station at Jakutsk in central Siberia reported a morning low temperature of a whopping -53°F! Twelve hours later, the HIGH temperature for the day was -45°F!

There are certain codes that weather observers use to report aspects of the current weather conditions aside from the temperature, pressure, humidity and winds. For example, there are codes that can be sent out that report blowing snow, or patchy fog, or dusty conditions. There are special codes to report thunder and lightning in the area, hail, freezing rain, or whatever whether is presently occurring. One code that meteorologists don’t get to use very often represents “visibility obstructed by smoke”. Typically in the United States, weather observers use this code when there are forest fires in the area; basically, they are just informing the other meteorologists that the observations of visibility in the area might be faulty due to problems with smoke in the air. However, “visibility obstructed by smoke” is actually a pretty common weather observation in Siberia; just today I looked at the charts, and that was the observation from a number of stations in eastern Russia and Mongolia. I certainly hope that there are no forest fires right now in Siberia—I can’t even imagine fighting a forest fire when the air temperature is more than forty degrees below zero!

However, the smoke that is obstructing visibility in Siberia probably isn’t due to forest fires. It’s probably coming from chimneys and smokestacks in eastern Russia. Now, of course, there aren’t a LOT of people and industries out there in Siberia, but there are SOME. When the air is as cold as it is in Siberia in the winter, the air is extremely dense and heavy compared to the air aloft. That means that the air is hard to lift up from the surface and mix with the warmer, lighter air aloft. Meteorologists describe a situation like this as being “stable”. Stable conditions happen in the US, too—it’s part of the reason why thunderstorms don’t generally happen in the winter, for example, since stable conditions mean that the dense, heavy air at the surface is hard to lift into the updraft of thunderstorms. However, the air in Siberia is EXTREMELY stable and dense, meaning that there is no way for the air near the surface to get away from the surface and mix with clean air aloft. Any pollutants that get added to the air over Siberia are stuck near the surface for days or even weeks before diluting into the atmosphere aloft. Environmental engineers sometimes say that the solution to air pollution is dilution, meaning that no one really notices air pollution problems when air at the surface can easily dilute or mix with cleaner air aloft. In winter in Siberia, the residents don’t just have to battle some of the most brutal temperature conditions on earth, but they are also stuck with terrible air quality for months at a time.