Observed changes in maximum and minimum temperatures over China- Pakistan economic corridor during 1980-2016

Pakistan is located in one of the fast temperature rising zones and hence, highly vulnerable to climate change. The dynamic variations of the maximum (Tmax) and minimum (Tmin) temperatures pose potential risks to the local people. Thus, the present study assessed spatiotemporal changes in Tmax and Tmin over China-Pakistan Economic Corridor (CPEC) during 1980-2016 based on the 48 meteorological stations across the CPEC. The non-parametric Mann-Kendall (MK), Sen's Slope (SS) estimator, Sequential Mann-Kendall (SQMK), and least square method tests were used to assess the long-term trends in Tmax and Tmin time series during 1980-2016. The results indicate that the trend of Tmax has significantly increased at the rates of 0.22, 0.37, 0.20, 0.23, and 0.31 °C per decade in winter, spring, summer, autumn, and annual time scales, respectively. Similarly, the Tmin exhibited a significant positive trend in winter, spring, summer, autumn, and annual time series with the rates of 0.33, 0.39, 0.25, 0.27, and 0.36 °C per decade, respectively. The spatial distributions of Tmax and Tmin represent a warming trend over the whole country; however, the seasonal and annual Tmax (Tmin) exhibited sharp increasing trends in the northern and southwestern mountainous (southern, southwestern and southeastern) regions of the country. According to the mutation test, most of the abrupt changes in seasonal and annual Tmax and Tmin trends have been detected during 1995-2010. The present study recommends that forthcoming studies should focus on the factors responsible for the spatial and temporal variability of Tmax and Tmin in the target region.