A Numeric Classification of Climate

As one endeavors to create a system of categorizing different climatic types, he soon discovers that it is not an easy process. There are many factors and elements of climate which must be considered. The world also has an infinite number of unique climates that change through time. There are no abrupt changes from one climatic province to another as one might think by looking at a climate map. Each zone gradually meshes into the next adjoining zone, and the real difficulty lies in trying to determine an appropriate point to plot a division line. There are several important methods of alleviating this problem, but the time element often causes climatic conditions to change. This is why many scientists only use conditions for the last thirty years as a basis in determining a climatic classification.' One important method of determining climatic boundaries is to examine visible vegetative changes from one climatic province to another. Tree lines, for example, are particularly helpful in determining the boundaries of frigid climates whether in polar or high altitude regions. It can also work to distinguish arid zones from more humid zones, although these boundaries are less distinct. In humid climates having marked dry seasons, the edge of the deciduous forest is sometimes used in determining a climatic boundary, although moisture content of the soil at different times of the year perhaps would be better