NORMALIZED DIFFERENCE WATER INDEX APPLIED TO DIFFERENTIATION OF THE GROWING SEASONS

In earlier studies, we conducted joint assessment of climate change in recent decades and change of vegetation cover in the taiga zone of Russia. We used Normalized Difference Vegetation Index (NDVI) to assess vegetation cover change. We found that shrub vegetation is important indicator of climate change in the Northern regions of Russia. Previously, we assessed change of climate parameters and vegetation cover within different growing seasons (periods of the calendar year when the surface air temperature is above +5 degrees C and +10 degrees C). These are the periods of active growth of the biomass. The differentiation of the growing seasons in our study we performed in manual mode according to the data collected on meteorological stations. For the purposes of extrapolation of the obtained dependencies on areas where meteorological stations are absent, we need a tool that allows to supply the differentiation of growing seasons in the automated mode, using remote sensing data. Normalized Difference Water Index (NDWI) proposed by B. Gao allows to determine beginning of the growing season and beginning of the leaves yellowing. Currently we have designed the technique for automation of differentiation of the growing seasons using NDWI and studied its application. The study was partially supported by the Russian Foundation for basic research (RFBR), research project No. 14-05-00858 A.