Spatio-temporal variation of agricultural drought in the barind region of Bangladesh: an application of a Markov Chain model

The Barind region of Bangladesh is severely affected by agricultural drought. A geostatistical approach had been conducted to summarize the spatio-temporal variation of agricultural drought in this region. A Markov chain model of higher order has been used to evaluate probabilities of getting a sequence of wet-dry weeks over this region from the rainfall data recorded in 12 rainfall gauge stations for the period 1971-2008. A drought index (DI) considering crucial parameters (DI=0~1.00) has been used to estimate the severity of agricultural drought. Geospatial analysis has been conducted to delineate the spatial extent of agricultural drought of different severities in different seasons. The probability of three consecutive dry weeks and probability of at least 10 and 12weeks was also calculated to find out the suitability of agricultural production. The maximum variation of agricultural drought index (DI=0.12~0.43) was found during the pre-kharif (March to May) and kharif (June to October) (DI=0.47~0.81) seasons. However, no variation in drought index (DI=0.01~0.03) was found during the rabi (November to February) season. The results of this study might be useful to agricultural planners and irrigation engineers in identifying areas where agricultural development should be focused as a long-term drought mitigation strategy.