NDVI anomaly for drought monitoring and its correlation with climate factors over Mongolia from 2000 to 2016

Drought is a frequent phenomenon of Mongolia in the last 17 years. The imbalance between the potential evaporation and precipitation amount during the growing season usually causes drought condition which may pose a threat to the environment and human activities. Therefore, gathering a frequent information about the drought severity and its spatial and temporal distribution is required for drought effects mitigation. In this study, the drought severity and its spatial distribution over Mongolia have been mapped, based on the normalized difference vegetation index (NDVI) anomaly during the growing season for 2000 to 2016. The results indicated that Mongolia experienced mild to severe drought during the 17 years and the extremely affected years were 2001, 2007, 2002, 2005, 2004, 2009 and 2006 respectively when 41%-57% of the country was under mild to severe drought conditions. The temporal correlation analysis indicated that growing season NDVI anomaly variation was correlated with both climatic variables, but slightly more significantly correlated with precipitation anomaly (r = 0.46, p < 0.005) than temperature anomaly (r = - 0.40, p < 0.005). Meanwhile, the analysis of the spatial correlation between NDVI anomaly and two climatic variables varied according to the land cover type and plants growth environments.