Winter 2010/11 and the Arctic Oscillation

Snow and freezing temperatures turned out to be some of the weather stories of the 2010/11 winter on the Northern Hemisphere (while the Southern Hemisphere experienced some severe rain this summer), and again, climate change is back on the agenda. With the big freeze in Europe and the severe winter storms on the US East Coast, some may start to believe that global warming turns into global cooling instead. Apparently this is a much more complex picture than just warmer temperatures across the globe. Colder winters could even be there because of climate change. But whatever the weather, a look at the temperature patterns during these two major cold spells also revealed a pattern of a much warmer Northern winter in some of the Arctic regions, such as the North of Alaska, Canada, Northeastern Russia and Greenland. This has been caused by the Arctic Oscillation which shifted the usual temperature patterns, channeling Arctic cold air southwards into the densely populated regions. The areas being much warmer than on average have been much less acknowledged by the media because these above-normal temperatures affected much less people than the below-average temperatures in the highly populated regions. Amongst the events that caught less attention in the news was the to cancellation of the New Year’s snowmobile parade for the residents of Iqaluit, capital of the Canadian territory of Nunavut. This was caused by the unusual warmth and shows that the perception of this winter’s temperatures is a mainly a question of the perspective under which we observe these weather patterns.
To visualise and understand the impact of the changed weather patterns on the majority of people I used satellite data of NASAs MODIS sensor (on the Aqua satellite) and reprojected this data using my gridded cartogram method. The resulting map thus gives every person the same amount of space, while depopulated areas are given minimum space. The map preserves geographical references so that the relation of land surface temperature anomalies to the population distribution becomes apparent. Comparing this map to the original satellite data, the impact of the two cold spells (early December in Europe and late January in North America) onto the densely populated areas becomes visible, while it can also be recognised how few people live in the unusually warm Arctic region. The colours in this map refer to relative land surface temperature differences to the same time period in the previous years since 2003 (thus do not reflect absolute temperature values, meaning that red areas can still be cooler than blue areas).
The following three maps help us to understand the impact that these temperature anomalies have on people’s lives, and complements the UK snow map which I published on this website in December. The maps do also allow for a much broader comparison of these conditions (unlike the single snapshot of snow cover which was shown on the UK snow map), also in places that may have been less talked about in terms of weather conditions. And lastly, the maps do also show that this map projection can be used as a meaningful way of visualising not only the social space, but also the physical environment and understand this from a new perspective. Here are the maps:
Global land surface temperature anomalies in January 2011:

Global temperature anomalies in January 2011
(click for larger map)

Temperature land surface anomalies on the Northern Hemisphere in December 2010:

Temperature anomalies on the Northern Hemisphere in December 2010
(click for larger map)

Detailed view of land surface temperature anomalies in Europe in December 2010:

Detailed view of temperature anomalies in Europe in December 2010
(click for larger map)
(see also the UK snow map showing a different view on the situation mapped here)

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