Assessment of Temporal and Spatial Variation of Pan Evaporation with Related Climatological Factors in Bangladesh

Pan evaporation is an effective way to analyze the multidimensional impact of climate change on irrigation water requirement since pan evaporation measures the integrated effect of radiation, wind, temperature and humidity on the evaporation from an open-water surface. The characteristic trends of pan evaporation and related climatological factors, as developed in this paper, indicate that most of the regions of Bangladesh have undergone a significant amount of decrease in evaporation through the years. The reduction in sunshine duration as a consequent of climate change can be attributed to be the principal reason for the decrease in evaporation. The spatial distribution of seasonal variation of pan evaporation along with solar radiation and humidity was analyzed, and solar radiation seemed to have the major influence on evaporation. The study also reveals that summer and spring are the seasons of highest evaporation in most of the regions. The characteristic trend and spatial distribution of seasonal pan evaporation correlated with related climatological factors developed in this study could aid in water resources development and planning for irrigation purposes.