ON VARIABILITY OF THE VEGETATION INDEX NDVI IN THE FOOTHILL AREAS OF THE NORTHERN CAUCASUS ACCORDING TO SATELLITE MEASUREMENTS

Abstract

The study of long-term climatic changes is carried out based on the data of the normalized relative vegetation index NDVI, which is a characteristic of phytobiomass and is used to describe the ecological situation, the amount of contamination and productivity of land. This theoretical work is based on the statistical and mathematical processing of MODIS satellite data (EOS Terra, Aqua), with the help of which the temporal and spatial variations of the NDVI vegetation index for the southern regions of the Russian Federation are studied. Several regions were selected, which located in mountainous or foothill areas on the territory of the North Ossetia-Alania, located in the central part of the North Caucasus. For each region, 20-year data series were obtained, each point of which is the NDVI index averaged over two weeks. With the help of these data series, the annual behavior of the NDVI index and its long-term variation are investigated, which shows the shift of a favorable growing season to an earlier period of the year. The annual integral characteristic of the NDVI index was used, which characterizes the long-term changes in the vegetation index in the studied regions. A statistical analysis of the series of integral characteristics was carried out, the parameters of linear regression were determined. The behavior of these characteristics for the foothill and lowland regions of North Ossetia-Alania indicates the presence of long-term trends in the changing conditions of the growing season. For the southern regions of the Russian Federation, observational data show a relationship between trends in NDVI changes with a long-term improvement in climatic conditions for plant vegetation and changes in conditions during cold periods of the year. This factor should be taken into account in economic activities in the southern regions of the Russian Federation.