Transitory Impact of AO is the ‘Good News’

The Bad News?
More Permanent Changes May Be Occurring!

Impact of Arctic Oscillation on Winter Temps

[Stay Tuned …]

Click image to enlarge. See  Kingdom United by Ice for detailed data and charts. Image Credit: NASA EO.

NASA image compares December 2009 temps to the average December temps between 2000 and 2008. Blue (red) for colder (warmer) than average land surface temps.

The Arctic Oscillation (AO), a climate pattern, impacts  winter weather in the Northern Hemisphere. The Arctic is dominated by a low-pressure air mass, while the mid-latitudes (around 45 degrees North, about the latitude of Montreal, Canada or Bordeaux, France) are governed by high pressure systems.

The strength of the high- and low-pressure systems oscillates. Weaker than normal systems cause the pressure difference between the two to decrease, allowing Arctic air to escape south and warmer air north. A weaker-than-normal AO is defined as “negative.” Strong high and low pressure systems characterize positive AO.

AO was strongly negative during Dec 2009. This image  observed by MODIS on NASA’s Terra satellite shows cold Arctic air impacting land surface at midlatitudes, while Arctic land, like Greenland and Alaska, was much warmer than usual. NASA Earth Observatory image by Kevin Ward. Caption by Holli Riebeek. Edited by FEWW.

See    Kingdom United by Ice for detailed data and charts

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