Forecasting critical dry spells in dl1 - a case study from anamaduwa

Abstract

Daily rainfall data(l950-2005) in Anamaduwa were analysed and useful information on the lengths (LDS1-LDS4) and the starting dates (SD1-SD4) of four critical dry spells were obtained. The mean duration of LDS1- LDS4 were 37,35,46 and 50 days respectively. More than 75% of the fourth critical dry spell occurred prior to the period 12-18 December and continued up to 2-3 weeks in January. Regression models (p< 0.001) were developed to forecast starting dates of the second, third and fourth critical dry spells. Log normal distributions were fitted for the length of the four critical dry spells.