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

Abstract—The results of estimates 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 are presented. According to the results of field geobotanical studies, it has been shown that the productivity of meadow vegetation has exceeded the productivity of steppe vegetation. As a result of ground-based spectral measurements, it is shown that they can be identified by monitoring the spectral reflectivity of meadow and steppe vegetation. The analysis of MODIS satellite data (based on the normalized differentiated vegetation index (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)) has revealed that the values of the studied indices for meadow vegetation have significantly exceeded the values for steppe vegetation, except for the land surface temperature (LST), which has been higher for steppe vegetation than for meadow vegetation. High positive correlations between vegetation indices characterizing biomass (NDVI, EVI, LAI, and NPP) and hydrothermal conditions (LSWI and FPAR) for meadow and steppe vegetation have been determined. However, the correlation coefficients between NDVI and LST and between EVI and LST for steppe vegetation have been low. Based on the maps of the spatial distribution of the NDVI of meadow and steppe vegetation according to Landsat 8 data for July 29, it has been shown that the NDVI has significantly differed for the studied vegetation types. For meadow vegetation, the NDVI value has been significantly higher than that for steppe vegetation.