Characterization of pan evaporation with related climatological parameters of Bangladesh

Abstract

Bangladesh is an agricultural country. Agriculture is the single largest producing sector of the economy since it comprises about 18.6% of the country's GDP and employs around 45% of the total labour force. It has around 8 million hectares of cultivable land and total irrigated land is around 56%. Agriculture determines people’s lives and livelihood of this region. Pan evaporation is a measurement that combines or integrates the effects of several climate elements: temperature, humidity, rain fall, drought dispersion, solar radiation. Pan evaporation measurements enable farmers to understand how much water their crops will need. It is an effective way to analyse 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 spatial distribution of seasonal variation of pan evaporation along with solar radiation and humidity was analysed, 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 the irrigation water resources development and planning. Results of previous studies are analyzed and also enhanced the knowledge of this area. So this study is essential in worldwide especially in Bangladesh where agriculture plays a vital role to estimate the agricultural water demand in the changing environment for long term water resources and development.