ETo Variation in Pakistan in Changing Climate

Abstract

Pakistan has an agrarian economy where climate change and the consequent threat of global warming has become a great challenge. Out of two major cropping seasons in the country, Kharif is more important. Reference crop evapotranspiration (ETo) is one of the most important agrometeorological parameters. In this region, ETo profile has been analyzed on a long time basis for Kharif season. The climatic data for maximum & minimum temperatures, mean relative humidity and mean wind speed is utilized for the two recent periods 1971-2000 & 1981-2010, for Pakistan. As the study region has a diversified type of climate, therefore, FAO Penman-Monteith method has been employed for ETo. This method shows minor deviations from the actual evapotranspiration data throughout the year in the climate of Pakistan. To investigate the major dependence of ETo variation, all the input parameters have been fed into a statistical model. Regression equation shows that ETo difference is mainly dependent on wind speed and max temperature. Both the actual and simulated values for ETo for most of the data points remained very much consistent with the actual values. Their mutual correlation is 0.81 and significant at the 0.01 l evel. The outcome of the study is in agreement with the recent findings in the context of climate change and global warming