Climatic Regionalization
John E. Oliver
Captain John Smith proved that he was much more than a colonial adventurer when he wrote the following account of Virginia in 1607:
The sommer here is hot as in Spaine; the winter colde as in Fraunce or England. The heat of sommer is in June, Julie, and August, but commonly the coole Breeses asswage the vehemencie of the heat. The chiefe of winter is halfe December, January, February, and halfe March. The colde is extreame sharp, but here the proverb is true that no extreame long continueth (Tyler, 1907).
In this succinct paragraph, this early observer outlined the essence of climatic regionalism. First, he identified a baseline: the previously experienced conditions encountered in Spain, France, and England; then, by comparing the nature of the seasons of the new area with those already known, Smith characterized the climatic identity of early Virginia.
This climatic identity differentiates one climatic region from another. But to recognize exactly what separates one regional identity from another is not a simple task. The climatic elements of any region distinguish that region not by their presence or absence, but by a difference in their character. Climatic elements do vary systematically from place to place, sometimes rather abruptly but mostly over considerable distance so that boundary definition is often arbitrary. Adding to the problem is that climate is an abstract concept that represents the summation of all interacting atmospheric processes at a location over a stated, usually lengthy, period of time. As such, it does not exist at any given moment. Thus, although it is necessary to systematize the long-term effect of interacting atmospheric processes, the manner in which they may be grouped is variable. As such, the objective of this contribution is to provide a rational description of the climatic regions of North America and to examine their climatic identities.
Climatologists today are in the fortunate position of having available an enormous amount of climatic data. The development of the World Wide Web and CD-ROMs has opened new vistas for those who use climatic data. Of course, this has not always been the case, with the result that perceptions of climates of North America have changed over time. The charitable view of the early Norse explorers, who found Greenland and Vinland nominally attractive, differed from the perceptions of nineteenth century Russians, whose image of Alaska as a chaos of snow-covered mountains and frigid climates induced them to sell off rather cheaply. The descriptions of Ponce de Leon's discovery of Florida and Coronado's quest for gold in the desert South-
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