Continentality: A basic climatic parameter re‐examined

Continentality, a basic control of climate, is difficult to quantify in terms of the factors that govern it. As a result, a chief consequence of continentality, annual range of temperature, has been used as a surrogate. Annual range, however, is determined primarily by seasonal variations in radiation receipts, and attempts at constructing continentality indexes have attempted to compensate for this variation by dividing annual range by the sine of the latitude. In so doing it has been assumed that the latitudinal variation of seasonal radiation increases monotonically with latitude. It is shown that this is not the case; thus, indexes of continentality based on this assumption are flawed. A continentality index based not on annual range of temperature, but on residuals from the regression line of annual temperature range on latitude, is formulated. The result is a maximum of continentality in the location suggested by a qualitative look at the factors influencing it. Additional advantages to this approach are specified.