| Abstract: | The traditional two-dimensional concept of latitudinal natural geographical zones is challenged on the ground that it ignores the altitude factor and differences in the character of the surface environment. An alternative three-dimensional model of zonal systems is proposed, in which so-called landscape levels corresponding to particular geomorphic levels are distinguished in terms of radiation balance and elevation. The zonal systems are combined into four worldwide groupings: (1) an inner terrestrial group corresponding to a rocky surface environment; (2) an outer terrestrial group corresponding to a cryogenic rocky environment; (3) an outer ice group, corresponding to ice-covered segments of the earth's surface, and (4) an oceanic group. The paper is devoted to the first three continental groups of zonal systems. The traditional zonality is found to be well expressed in the inner terrestrial group, but the outer groups reflect mainly Markov's law of polar asymmetry (see Soviet Geography, February 1964). |
