New paper finds “surprisingly, there are many US weather stations that show cooling” over the past century
http://hockeyschtick.blogspot.com/2014/03/new-paper-finds-surprisingly-there-are.html
A paper published today in the Journal of Climate finds, contrary to popular belief, that US “monthly maximum temperatures are not often greatly changing — perhaps surprisingly, there are many stations that show some cooling [over the past century]. In contrast, the minimum temperatures show significant warming. Overall, the Southeastern United States shows the least warming (even some cooling), and the Western United States, Northern Midwest, and New England have experienced the most warming.”In essence, this paper is saying the weather/climate has become less extreme, with little to no change in maximum temperatures “and even some cooling” of maximum temperatures in some stations, and warming of minimum temperatures. Thus the temperature range between minimum and maximum temperatures has decreased, a less extreme, more benign climate.
Note these results are after the huge up-justments made to the US temperature data and urban heat island [UHI] artificial warming, which could account for all or most of the warming of minimum temperatures.
Journal of Climate 2014 ; e-View
doi: http://dx.doi.org/10.1175/JCLI-D-13-00283.1
Trends in Extreme United States Temperatures
Jaechoul Lee*
Department of Mathematics, Boise State University, Boise, Idaho
Shanghong Li and Robert Lund
Department of Mathematical Sciences, Clemson University, Clemson, South Carolina
Abstract
This paper develops trend estimation techniques for monthly maximum and minimum temperature time series observed in the conterminous 48 United States over the last century. While most scientists concur that this region has warmed on aggregate, there is no a priori reason to believe that temporal trends in extremes and averages will exhibit the same patterns. Indeed, under minor regularity conditions, the sample partial sum and maximum of stationary time series are asymptotically independent (statistically). Previous authors have suggested that minimum temperatures are warming faster than maximum temperatures in the United States; such an aspect can be investigated via our methods. Here, statistical models with extreme value and changepoint features are used to estimate trends and their standard errors. A spatial smoothing is then done to extract general structure. The results show that monthly maximum temperatures are not often greatly changing — perhaps surprisingly, there are many stations that show some cooling. In contrast, the minimum temperatures show significant warming. Overall, the Southeastern United States shows the least warming (even some cooling), and the Western United States, Northern Midwest, and New England have experienced the most warming.
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