Long‐term changes in extreme air temperature in Nuwara Eliya: a case study from Sri Lanka

Abstract

Long‐term changes in extreme air temperature at Nuwara Eliya (a high‐elevation observatory located in the western slopes of the central mountainous region of Sri Lanka) are examined. The present work is limited to a linear trend analysis of daily maximum and minimum air temperature series of the period 1926–2015. The statistical significance of the trend is estimated using the Mann‐Kendall test. There is a significant reduction in the diurnal temperature range (DTR) in Nuwara Eliya. The magnitude of the reduction is −0.23 degC per decade and is due to the increase in the daily minimum air temperature. No significant increase or decrease in the daily maximum air temperature was evident from the data. There is a strong inverse correlation between the standard deviation (which is related to the temperature variability) and the mean daily minimum air temperature. The increase in minimum temperature is not uniform throughout the year as the minimum temperature of the cold season has increased, while it has remained the same for the warm season, thereby reducing the overall DTR.