There’s a colorfully sharp temperature contrast in Greenland, one might think it was “red hot” there. Hmmm where have we seen something like this before? The warm red pocket over southern Greenland and Eastern Canada is caused by a blocking high pressure cell, while all the cold Arctic air flows around it. Readers may recall that a blocking high was responsible for the Russian heat wave this summer also, despite many early erroneous claims that “global warming caused it”(look at the list at the end). NOAA’s analysis concluded it had everything to do with weather, and not greenhouse gases saying:
Despite this strong evidence for a warming planet, greenhouse gas forcing fails to explain the 2010 heat wave over western Russia. The natural process of atmospheric blocking, and the climate impacts induced by such blocking, are the principal cause for this heat wave.
We have the same blocking situation here. The difference? In Nuuk Greenland today, the temperature was not “red hot”, but a cool 6°C/42°F for the high. Hint: If you want to see current surface temps on the image below, download the Google Earth KMZ file link at the end of this story, then enable “weather” as an overlay in GE.
From NASA Earth Observatory: The first week of December was a chilly one for much of Europe and parts of the United States. This image shows the temperature of the land surface for December 3-10, 2010, compared to the average temperature for the same period between 2002 and 2009. The measurements are from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite.
Clearly, 2010 was cooler than average in northern Europe and the eastern United States. Greenland and parts of northern Canada, however, were exceptionally warm. This temperature pattern was caused by the Arctic Oscillation.
The Arctic Oscillation is a climate pattern that influences winter weather in the northern hemisphere. It describes the relationship between high pressure in the mid-latitudes and low pressure over the Arctic. When the pressure systems are weak, the difference between them is small, and air from the Arctic flows south, while warmer air seeps north. This is referred to as a negative Arctic Oscillation. Like December 2009, the Arctic Oscillation was negative in early December 2010. Cold air from the Arctic channeled south around a blocking system over Greenland, while Greenland and northern Canada heated up.
The unusual cold brought heavy snow to Northern Europe, stopping flights and trains early in December. Cold temperatures and snow also closed roads and schools in the eastern United States and Canada during the first week of December. The diagonal path of a powerful winter storm is visible as a streak of cold across the Upper Midwest of the United States.
- Associated Press. (2010, December 14). Bone-chilling cold plods into Northeast US. Accessed December 15, 2010.
- BBC News. (2010, December 3). Europe’s deadly cold snap maintains grip. Accessed December 15, 2010.
- Climate Prediction Center. (2010, December 15). Arctic Oscillation. NOAA National Weather Service. Accessed December 15, 2010.
- CNN. (2010, December 2). Heavy snow creates European travel chaos. Accessed December 15, 2010.
- NOAA National Climatic Data Center. (2010, December). State of the climate: National overview for November 2010. Accessed December 15, 2010.
NASA Earth Observatory image created by Jesse Allen, using data provided courtesy of the NASA/GSFC Distributed Active Archive Center. Caption by Holli Riebeek.