Variability and changes of the surface air temperature in the Badulla District of Sri Lanka

Abstract

The surface air temperature holds the highest significance as it impacts the other weather elements in a particular area. Rising surface air temperatures are linked to widespread changes in weather patterns, which have further effects on human health and well-being, agriculture, and ecosystems. Many scholars have studied temperature trends in Sri Lanka; however, district-level analyses in agriculturally dominant areas, such as Badulla, remain limited. The objective of this research was to fill this gap and analyse the trends and changes in the surface air temperature in the Badulla District from 1993 to 2022. The surface air temperature data were obtained from the Sri Lankan Meteorological Department. The averages of surface air temperature data for the periods of 1993-2002, 2003-2012, and 2013-2022 were studied. Mann-Kendall (MK) test and Sen’s slope estimation were employed to identify temperature trends and to determine the magnitude of those trends. The findings suggest that the surface air temperature at Badulla in May was the hottest month in three decades, and a similar feature is also seen in Bandarawela for the first two decades. The months of January and December were the coldest months across all three decades in both areas. The study revealed statistically significant decreasing trends in the monthly minimum surface air temperature in Badulla for November and December. Monthly maximum surface air temperatures in Badulla showed statistically significant decreasing trends from February to October, with rates ranging from 0.04°C to 0.08°C per year. It could be concluded that the direction and magnitude of the temperature trends differ within the district. The findings highlight the need for location-specific climate adaptation strategies in Badulla District, particularly to support agriculture, water management, and tourism planning.