The image below shows the median trend of monthly lower tropospheric temperatures from 1982-2007 as determined by the Earth Trend Modeler from the Microwave Sounding Unit (MSU) image series processed by Remote Sensing Systems. These data are spatially coarse, but they represent a critical resource in understanding atmospheric dynamics. In the image below we can see that the strongest trends are in the Arctic. The image has been contrast stretched to a range between +/- 0.008 degrees Celsius per month, which translates to almost 2.5 degrees over the period of this series. It is interesting to note that the highest increases in temperature are in the northern hemisphere.
The second image (below) shows the monotonic trend analysis for MSU lower troposphere temperatures. Trend monotonicity measures the degree to which a trend is consistently increasing or decreasing. In the Earth Trends Modeler, trend monotonicity is measured using the Mann-Kendall statistic. Here the picture is quite different – the region with the most consistent increase in lower tropospheric temperatures is the tropics. Although the eastern Pacific is less pronounced, this is probably only a result of persistent ENSO events in that region that reduce the measure of monotonicity.