Variability of precipitation extremes and drought intensity over the Sikkim State, India, during 1950–2018
2022
Dubey, Swatantra Kumar | Ranjan, Rakesh Kumar | Misra, Anil Kumar | Wanjari, Nishchal | Vishwakarma, Santosh
The rainfall pattern analysis and extreme precipitation indices are executed using the India Meteorological Department (IMD) gridded data positioned in the Sikkim region, which is vastly susceptible to rain-induced hazards. In this study, 14 different extreme precipitation indices were calculated using the CLIMPACT-2 from 1951 to 2018. Standardized Precipitation Index (SPI) was determined for 3-, 6-, 12- and 24-month drought, and interpolation methods were applied for spatial analyses of extreme indices in the region. The MAKESENS excel tool was used to perceive the trend in daily precipitation and extreme index. The Mann–Kendall (MK) non-parametric test was applied to notice long-term (1951–2018) trends in extremes indices. The results show an increase in the warm day’s frequency and the consecutive dry days (CDD) increases over the area. The indices like annual rainfall (PRCPTOT), consecutive wet days (CWD) and R20 showed the changes in the north, south and west part of study area. Most extreme indices show a negative trend, but the R10 index shows a positive trend over the area. The RX1DAY, RX3DAY, RX5DAY and SDII changes occur mainly in the Sikkim western and northern parts. SPI values of longer time scales (3 and 6 months) have not improved significantly. The SPI 12-month and 24-month droughts, on the other hand, revealed negative trends and drought year sensitivity. This study complemented the extreme precipitation indices analysis by linking the entire precipitation dataset since the mid-twentieth century and plugs the gap in the precipitation pattern in the Sikkim state.
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