Reasons for long-term dynamics of NDVI (MODIS) averaged for arable lands of municipalities of Belgorod region

One of the basic products of the Internet service VEGA is the cartograms of the vegetative index NDVI (MODIS) averaged for arable land of municipalities of Russia, updated weekly. The article presents the results of analysis of its long-term dynamics for the period of 2001−2016 for the municipalities of Belgorod Region. The main causes of the observed dynamics are analyzed. It was found that the most significant factors are the changes in crops acreage and the climatic conditions of the growing season. The date of the first NDVI value at the start of the season correlates well with air temperature data. But the trend of this indicator for the period of research (2001−2017) on the territory of the region is not revealed. An indistinct 5−7 years periodicity of local minima and maximums of this indicator is observed. Dynamics of crops acreage has stronger effect on the date of seasonal NDVI maximum than trends of weather conditions (which act towards the onset of an earlier peak in the growing season). It leads, albeit to a weak, but increasingly later NDVI seasonal peak date in the second half of the analyzed period. The main factor of the dynamics of the magnitude of the seasonal NDVI maximum in Belgorod Region is dynamics of the cropping rotations, the combination of crop yields and acreage. The received data should be taken into account when using the Internet service VEGA for operative monitoring of crops. © 2018 Space Research Institute of the Russian Academy of Sciences. All rights reserved.