Informative Value of Spectral Vegetation Indices for the Meadow and Steppe Vegetation Monitoring of Khakassia by Ground and Satellite Data

The article presents the results of the assessment of the possibility to identify meadow and steppe vegetation of Khakassia using ground and MODIS and LANDSAT 8 satellite data during the 2017 growing season. According to the results of field geobotanical studies, it was shown that the productivity of meadow vegetation exceeded the productivity of steppe vegetation. As a result of ground-based spectral measurements, it was shown that monitoring of the spectral reflectivity of meadow and steppe vegetation can be used to identify them. The analysis of MODIS satellite data (based on the NDVI, the enhanced vegetation index EVI, the land surface water index LSWI, the leaf area index LAI, the fraction of absorbed photosynthetically active radiation FPAR and net primary production NPP) revealed that the values of the studied indices for meadow vegetation significantly exceeded the values for steppe vegetation. The exception was the land surface temperature LST, which was higher for steppe vegetation than for meadow vegetation. High positive correlations between vegetation indices characterizing biomass (NDVI, EVI, LAI, NPP) and hydrothermal conditions (LSWI, FPAR) for meadow and steppe vegetation were determined. However, the correlation coefficients between NDVI and LST, EVI and LST for steppe vegetation were low. Based on the obtained maps of the spatial distribution of the NDVI index of meadow and steppe vegetation according to Landsat 8 data for July 29, it was shown that the NDVI index significantly differed for the studied vegetation types. For meadow vegetation, the NDVI value was significantly higher than for steppe vegetation.