REGIONAL-ANALYSIS OF TEMPERATURE EXTREMES - SPATIAL ANALOG FOR CLIMATE-CHANGE

The statistical theory of extreme values is applied to daily minimum a nd maximum temperature time series in the U.S. Midwest and Southeast. if the spatial pattern in the frequency of extreme temperature events can be explained simply by shifts in location and scale parameters (e. g., the mean and standard deviation) of the underlying temperature dis tribution, then the area under consideration could be termed a ''regio n.'' A regional analysis of temperature extremes suggests that the Typ e I extreme value distribution is a satisfactory model for extreme hig h temperatures. On the other hand, the Type III extreme value distribu tion (possibly with common shape parameter) is often a better model fo r extreme low temperatures. Hence, our concept of a region is appropri ate when considering maximum temperature extremes, and perhaps also fo r minimum temperature extremes. Based on this regional analysis, if a temporal climate change were analogous to a spatial relocation, then i t would be possible to anticipate how the frequency of extreme tempera ture events might change. Moreover, if the Type III extreme value dist ribution were assumed instead of the more common Type I, then the sens itivity of the frequency of extremes to changes in the location and sc ale parameters would be greater.