Monitoring meteorological and agricultural drought dynamics in Barind region Bangladesh using standard precipitation index and Markov chain model

The Barind region of Bangladesh suffers from frequent drought due to poor and delayed rainfall in pre monsoon and monsoon season. In the present study details analysis of rainfall data has been carried out for the years 1971-2010. Two well known drought indices, Standard precipitation index (SPI) has been used to evaluate the precipitation deficit, and Markov chain model used to quantify the drought in agricultural extent. Details analysis of spatiotemporal drought dynamics during Pre-Kharif (pre-monsoon) and Kharif (monsoon) have been carried out through drought indices map generated in a GIS (Geographical Information System) environment. Analysis and interpretation of these maps evaluate that meteorological drought is not always correspond to agricultural drought and a chronic agricultural drought can be occur because of a limited rainfall deficit. The study also identified that there is a statistically significant temporal correlation between SPI and Markov chain drought indices but spatial correlation is poor in pre monsoon season. In the Barind region meteorological drought shows a similar pattern in pre monsoon season but in monsoon season rainfall deficits shifts its position time to time and in certain pockets it is more frequent. In agricultural sphere, the Markov chain shows a very chronic pattern during pre-monsoon season in the entire area but in monsoon it behaves like meteorological drought. .