Meteorological drought analysis for Northwest Bangladesh

This paper describes meteorological drought which is a period marked by below normal rainfall. An attempt has been made to apply the method developed by Herbst et al. (1966), in order to determine the date of onset and termination, intensity index and severity index of drought. These indices enable the droughts to be compared in time and space irrespective of their seasonal occurrences. Half-monthly rainfall data for a period between 1962-95 for the fifteen stations in the northwest region of Bangladesh have been used for the present analysis. The study shows that there is no unique date of onset and termination of drought in the northwest region of Bangladesh. It occurs in a number of spells, the duration of which is random as expected. Variables like mean annual rainfall versus mean annual rainfall deficit and drought intensity versus percent of rainfall that occurred less than the mean rainfall in a spell are plotted to get a hold of their relationships. Except Bogra (R006), and most likely Nekmard (R193) and Shiganj (R215), rest of the stations in the region have similar drought characteristics.