Aridity Definitions and their Applicability

Abstract

In the first part of this article a review of various approaches to the problem of defining aridity is given and particular emphasis is placed on a critical analysis of different indexes used for this purpose, such as those developed by Köppen, de Martonne, Emberger, Gaussen, etc. For comparison, the modern water-balance concept, as developed by e. g. Thornthwaite, Penman and Budyko, is also discussed. In the latter part of the article, as an example of a practical study of aridity conditions, a summary is given of an investigation of agroclimatology in the Near East made by the author in co-operation with G. Perrin de Brichambaut. Comparisons are finally made between the outcome of calculations of various indexes for certain stations in the Near East for which the water-balance conditions were established during the above investigations.