Analysis of Temperature and Precipitation Trends Observed at Some Selected Districts of Punjab, Pakistan

Abstract

Present study examines the trends of extreme daily temperature and rainfall indices in some selected meteorological stations/districts of the Punjab. Due to paucity of data only six weather stations were selected from the whole Punjab, having data of 33 years for temperature and precipitation on daily basis. A set of 14 indices (recommended by climate ET) were used to calculate the trends over a period of 32 years (1985–2017) by using RClimDex (1.0) software package. These results showed that the number of tropical nights (TR20) and warm nights (TN90p) has been increasing in selected weather stations/districts and number for cool nights (TN10p) has been falling. Other temperature related indices trends such as, summer days, warms days, warm spell duration indicator (WSDI) and cool spell duration (CSDI) shows a mix pattern. The precipitation indices like SDII, RX1day, R10mm and PRCPTOT showed an increasing trend in some selected stations. Most of the trends were not sig­nificant at level of 0.05 % while maximum day temperature increase has been observed at five out of six selected stations. Similarly, an average increase in precipitation in the vicinity of 3 mm per decade has been noted. The annual total rainfall and number of heavy rainfall days has also increased by 18 mm and 8.4 mm respectively during each decade. The analysis identified and highlighted a slight change which was not temporally and spatially rational. However, there is need to more and adequate yearly data of different weather stations across the Punjab to identify the ongoing apparent and impeccable changes in climate of the Punjab province.