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.

中文翻译：

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努沃勒埃利耶州极端气温的长期变化：以斯里兰卡为例

研究了努沃勒埃利耶（Nuwara Eliya）（位于斯里兰卡中部山区西部斜坡上的一个高海拔天文台）的极端气温的长期变化。目前的工作仅限于对1926年至2015年期间每日最高和最低气温序列的线性趋势分析。使用Mann-Kendall检验估计趋势的统计显着性。努沃勒埃利耶的昼间温度范围（DTR）大大减少。每十年减少的幅度为-0.23摄氏度，这是由于每日最低气温的升高所致。从数据来看，每天最高气温没有明显增加或减少。标准偏差（与温度变化有关）与平均每日最低气温之间存在很强的反相关关系。随着寒冷季节的最低温度升高，全年最低温度的升高并不均匀，而温暖季节的最低温度则保持不变，从而降低了总体DTR。