FUTURE CHANGES OF METEOROLOGICAL DROUGHT OVER BANGLADESH USING HIGH RESOLUTION CLIMATE SCENARIOS

ABSTRACT: Drought has a significant impact over the socioeconomic condition of Bangladesh as it has an agriculture based economy. The current situation of climate change related to agriculture's impact, impact on food security and national policy in these regards need especial scholarly attention in Bangladesh. To assess the meteorological drought (by considering rainfall only), Standardized Precipitation Index (SPI) is used to diagnose drought which uses historic records of monthly rainfall data over Bangladesh. Droughts are categories as extreme (SPI <-2.0), severe (-2.0 < SPI <-1.5) and moderate (-1.5 < SPI <-1.0) droughts and frequencies of these drought events are compared with two time slices, namely, 1971-1990 and 1991-2010 of each 20 years of length. Historical analysis has suggested that extreme droughts are decreased whether severe and moderate droughts are increased during past two decades especially in the north western part of the country. Future drought conditions are also analyzed using 25km high resolution downscaled and projected climate data generated from the regional climate model known as PRECIS. The SRES A1B emission scenarios boundary data have used to run the simulations for a continuous period of 1971-2100. SPI values are also determined with these simulated time series data and validated with existing observed data from 1971 to 2010. It has found that model can capture observe climatology quite well. Considering seasonal (using 3 months SPI) drought events, all three types of droughts will be decreased in future years where there will be a comparative higher frequency of drought at mid 21st Century