Forecasting the coastal rainfall of burma

This paper describes an attempt to drive forecasting formulae for the mansoon rainfalls during the season, June to August, for the Arakan Coast, the Irrawaddy Delta and the Tenasserim Coast of Burma. The method used is partly synoptic and partly statistical. In the first place, the anomalies ( i.e. , deviations from long‐period mean values) of monthly pressure and temperature over the world from January to May in the years of extraordinarily deficient and excessive rainfalls are plotted on world maps. These maps are then examined with a view to finding features which are common to years of deficient rainfall and which are reversed in years of excessive rainfall. When such features have been found, the appropriate arithmetical data representing these features are correlated with the rainfalls of the three regions. Sir Gilbert Walker's methods are then employed for evaluating regression equations connecting the rainfall with the factors correlated. Forecasting formulae (regression equations) are developed separately for the Arakan Coast rainfall, the Irrawaddy Delta rainfall and the Tenasserim Coast rainfall. The total theoretical correlation coefficients between the forecast and actual rainfall are .80, .80 and .87 respectively.