Teleconnections between the sea surface temperature in the Bay of Bengal and monsoon rainfall in Bangladesh

To explore the teleconnection between sea surface temperature (SST) and summer monsoon rainfall in Bangladesh, this study examined 90 yrs (1912–2001) of monthly rainfall data for twelve stations for the months of May (pre-monsoon month), and June through September (monsoon months) and SST of the Bay of Bengal for the same time period at 2° by 2° grid cells. A significant positive correlation (0.64) was found between the All-Bangladesh Monsoon Rainfall (ABMR) and SST over the Bay of Bengal in the month of June. All other contemporaneous monthly correlations were not found to be significant. The SST over the Bay of Bengal was positively correlated with June rainfall at all coastal stations in Bangladesh, and significantly for the Comilla station. The prevailing wind has a south-easterly component at this station, due to deflection caused by the coastal hills. Thus, the orographic effect in the east and the north-eastern part of the country appears to enhance the rainfall amounts in that area. The SST over the Bay of Bengal is especially important at 89°, 93°, and 95° East longitudes for predicting the June rainfall in Bangladesh.