The diagram above serves as a reference frame. The middle stratosphere at 30 hPa has been off the scale cold since the end of November as the Arctic began to experience Polar night.
The great bulk of the northern landmasses are experiencing sub zero temperatures. The winds streaming out of the Arctic are warm by comparison with the air near Lake Baikal and the interior of Iceland. Reputedly China is experiencing its coldest winter for thirty years. The diagram below shows the circulation of the air and its temperature at 10hPa or 30 km in elevation.
The cold is due to the descent of mesospheric air in the circulation at left centred over Russia and spiralling in to the surface in the proximity of Lake Baikal. The warm ascending circulation on the right that is centred on the north Pacific is due to the persistent presence of high concentrations…
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