DROUGHT MONITORING USING STANDARD PRECIPITATION INDEX IN WESTERN NEPAL

This study used 28 meteorological stations’ monthly precipitation data for 42 years (1977 – 2018) as input to generate a standardized precipitation index (SPI) for winter and monsoon. SPI3 and SPI4 are used in winter and monsoon droughts to investigate frequency, duration, and severity. This study identified monsoon droughts in 1977, 1979, 1987, 2004, 2005, 2006, 2009, and 2015. The 1979 was an extreme monsoon drought event. It has been revealed that extreme and severe droughts dominated western Nepal in 1979. Similarly, winter droughts were identified in 1999, 2001, 2006, 2008, 2009, 2016, 2017, and 2018. The winter drought event of 1999 is an extreme drought. This episode is dominated by extreme and severe drought in western Nepal. Eight (winter and monsoon) major droughts have diverse natures in different areas. The drought dynamics in each episode are different at various altitudes. Winter and monsoon droughts have been observed frequently since 2000. SPI and Southern Oscillation Index (SOI) correlation patterns indicate that extreme drought and SOI are comparatively stronger than general events. Furthermore, the relationship between seasonal rainfall and SOI is strong in monsoon and weak in winter.