Satellite-based analysis and monitoring of agro-ecosystems and land degradation and desertification in Central Asia

Abstract

The Central Asia includes six countries (Kazakstan, Uzbekistan, Kyrgystan, Tajistan, Afganistan, Turkmenistan). Grassland degradation and desertification in the Central Asia has been accelerated over the past few decades due to increasing livestock grazing intensity and climate variability (Berger et al. 2013; Chuluun and Ojima 2002; von Wehrden et al. 2010). To restore, maintain, and enhance grassland condition and productivity in the Central Asia is the goal of many research and development projects in the region. However, these efforts have been hampered by the lack of (1) updated and accurate information on grassland dynamics, conditions, and productivity; and (2) the capacity to generate such information in timely manner. Satellite remote sensing has been playing an increasing role in characterization and monitoring of grassland condition and productivity (Kariyeva and van Leeuwen 2011; Li and Yang 2014; Sternberg et al. 2011). Most previous studies have used Normalized Difference Vegetation Index (NDVI) data from optical images to evaluate grassland condition and productivity in the context of land degradation and desertification (Emerson et al. 2010; Sternberg et al. 2011; Wang et al. 2014). Recently, a few studies in North American grasslands and Mongolia grasslands show that Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI) are better indicators of grassland condition and productivity (John et al. 2013; Wagle et al. 2014; Wang et al. 2010b). Here we reported preliminary results from a pilot project that evaluated satellite-based three vegetation indices (NDVI, EVI and LSWI) and land surface temperature (LST) for characterization and monitoring of grassland degradation and desertification in the Central Asia. It used MODIS data from 2000-2013 at selected areas (H22V04, H23V04). If proved to be useful, we will incorporate it into our satellite-based monitoring program and implement it for regional mapping and monitoring of grassland degradation and desertification in the Central Asia.