Spatial trends of maximum and minimum temperatures in different climate zones of Pakistan by exploiting ground-based and space-borne observations

Temperature is a key indicator of a changing climate. A trivial change in temperature can result in significant changes in weather patterns with severe repercussions on ecology and socio-economic conditions of an area. This study aims to assess the changing trends in maximum and minimum temperatures in five climatic zones of Pakistan, and compare ground-based with satellite data from AIRS over these climatic zones of Pakistan. Mann Kendall test has been used to signify the temperature trends in all zones and seasons while Sen's slope value has been used to measure the magnitude of the trends for the time period 1978 to 2016. Ground observations have been compared with AIRS satellite observations for ascending and descending air temperatures by employing correlation and mean bias error. The results show that AIRS product (AIRSX3STM) underestimates T-max and T-min in all zones of Pakistan with the underestimation being most prominent in zone A. The trend analysis for maximum and minimum temperatures shows an increase in temperatures for all climate zones. Overall, Pakistan's maximum temperature increased by 0.026 degrees C/year with the maximum increase of 0.05 degrees C/year during pre-monsoon, and the minimum temperature increased by 0.027 degrees C/year.