Climate variability impact on reference crop evapotranspiration computed using cropwat model

Current study attempts to analyze the sensitivity of reference evapotranspiration (ET_o) computed using CROPWAT model in central Punjab. Ludhiana experiences mean annual ET_o of 3.98±0.19mm/day, which is decreasing at the rate of 0.1mm/day/decade. Highest mean monthly ET_o of 6.94±0.49mm/day is observed in June and lowest of 1.54±0.19mm/day is observed during January. Correlation analysis between meteorological parameters and ET_o showed negative relationship between T_min (−0.60) and RH (−0.63) and positive with T_max (0.33), wind speed (0.69), sunshine hours (0.81) and solar radiation (0.81). Significant correlation between ET_o and weather parameters indicates that climate change will have significant effect on ET_o in the coming years, which can put tremendous pressure on existing overstressed water resources in the region and any increase in water demand requires careful water resource planning and development in future. More emphasis is thus needed to develop technologies for reducing water losses in reservoirs, conservation of rainwater, development of crop varieties requiring less water and agronomic manipulations leading to conservation and judicious utilization of available moisture.