colder here warmer there

Since December, a persistent extreme in regional atmospheric circulation is causing record-cold  in the US, northern Europe, and northern Asia. A friend at 70 deg. N in west Greenland yesterday complained 6 January of no possibility to dog sled because of above-freezing air temperature and insufficient sea ice formation. He was surprised to know that here Ohio, 3300 km to the south, air temperatures were 8 °C (14.4 °F) cooler! See the December 2009 departure from normal…

figure 4: air temp map for December 2009

Map of air temperature anomalies for December 2009. —Credit: National Snow and Ice Data Center courtesy NOAA/ESRL Physical Sciences Division. high resolution version.

“The regional contrasts in temperature anomalies resulted from a strongly negative phase of the Arctic Oscillation (AO). … The AO consists of opposing patterns of atmospheric pressure between the polar regions and mid-latitudes. In December 2009 the AO index value was -3.41, the most negative value since at least 1950, according to data from the NOAA Climate Prediction Center. ” – National Snow and Ice Data Center

Here’s a different projection of a more basic data set…besides the extreme cold especially in northern Eurasia, note the red areas where warmth has been prevailing.

LST anomalies WRT 1961-90
Land surface temperature departure from normal. – UK Met office

Is this cold period part of a pattern of climate change?

…one cannot judge with any certainty without understanding causes in extremes of the Arctic Oscillation. Further, weather and climate are not the same, occurring at different time and spatial scales. The current weather pattern that is bringing cold to the US and Eurasia, being persistent, seems to be straddling the spatial and temporal scales between weather and climate. That’s about all I can say without more study.

Stay warm out there (in the US and Europe) and keep cool there in Greenland! This pattern is expected to persist for weeks? longer!!