Климатический рубеж в степной зоне Восточно-Европейской равнины: индикаторы и размещение

For the independent delineation of the climatic transition zone and its monitoring in steppe zone of the European part of Russia different indicators, such as climatic (observation data, reanalysis), spectral (NDVI) and model (evapotranspiration), are used. The complex characteristics of the climatic transition zone in the Orenburg oblast for dry and wet years are defined. A heat load on man and bioclimatic conditions changes in terms of human thermal comfort are explored according to the position of the climatic transition zone. It has been established that a climatic transition zone, resulted from sharp climatic differences, is a natural transitional strip with qualitative transformation of a dry steppe landscape on comparatively short distances. Climatic gradients of the annual and July precipitation are recommended for the identification of the climatic transition zone. The gradients of mean annual and July temperature identify climatic transition zone in particular areas bordering with dry steppe zones. Spectral and model indicators of the climatic transition zone (NDVI gradients and evapotranspiration) are qualitatively connected with July precipitation gradients. The vegetation index NDVI is beneficial to the evaluation of climatic transition zone sensitivity to climate aridization and anthropogenic contribution to desertification dry steppe landscapes. In terms of human thermal comfort, the climatic transition zone should be considered in area zoning under natural and climatic conditions of population activity.