Trend Analysis of Rainfall in the Northern Region of Sri Lanka from 1970 to 2019

Abstract

Understanding the changes of long-term rainfall is vital for water resources management and climate mitigation strategies development. This study aims to evaluate the annual, seasonal, and monthly rainfall trends of the northern region of Sri Lanka from 1970 to 2019. The Mann-Kendall and Sen's slope tests have been used to analyze the trend and magnitude changes, respectively. The results show that the historical annual rainfall of Northern Sri Lanka has increased from 18.76 mm/decade to 37.68 mm/decade from 1970 to 2019. As per the seasonal pattern, the rainfall of the northeast monsoon has been reduced, while South west Monsoon rainfall has increased gradually in the Northern Region of Sri Lanka. There are fluctuating patterns in the monthly rainfall pattern, and November dominates in the monthly rainfall pattern, receiving more than 350 mm as the average. Changes in the rainfall pattern of the study area impact the physical and economic living environment.