Spatial and Temporal Variation of Drought Based on Satellite Derived Vegetation Condition Index in Nepal from 1982–2015

摘要: Identification of drought is essential for many environmental and agricultural applications. To further understand drought, this study presented spatial temporal variations based on satellite derived Vegetation Condition Index (VCI) annual (Jan–Dec), seasonal monsoon (Jun–Nov) pre-monsoon (Mar–May) scales from 1982–2015 in Nepal. The obtained NOAA, AVHRR (National Oceanic Atmospheric Administration, Advanced Very High Resolution Radiometer) climate data meteorological stations were used. VCI was used to grade the Mann–Kendall test linear trend analysis conducted examine trends Pearson correlation between climatic factors (i.e., temperature precipitation) also acquired. results identified that severe 1982, 1984, 1985 2000 all time scales. However, has increased at rate 1.14 yr−1 (p = 0.04), 1.31 0.03) 0.77 0.77) annual, scales, respectively. These VCIs indicated decreases drought. spatially, found some regions For instance, northern areas mainly Trans-Himalayan foothills lowlands Terai (southern Nepal) experienced normal VCI, i.e., no Similarly, Anomaly (AVCI) mostly negative before which deficient soil moisture. exceedance probability scale showed there a 20% chance occurring (VCI ≤ 35%) 35% (35% 50%) Drought linked with climates significant positively correlated VCI. occurrence Nepal need be studied comprehensive information understanding.