Effect of climate change and elevated CO2 on reference evapotranspiration in Varanasi, India - A case study

Evapotranspiration (ET) is the major component of hydrological cycle, and will affect crop water requirement future planning management resources under changing climate scenarios. In present study, an attempt was made to study sensitivity reference evapotranspiration (ETo) different climatic variables, effect temperature elevated CO2 on ETo using meteorological data (1973-2010) Banaras Hindu University (BHU), Varanasi. The FAO-56 Penman–Monteith method used estimate ETo, studied in terms changes temperature, solar radiation, wind speed vapour pressure deficit. combined levels by varying from 1°C 5°C, level 330 ppm 660 ppm. simulation results showed that mean (Tmean) influenced annual most followed radiation (Rs), deficit (VPD) (U2). There are about 18.20, 13.80, 7.90 5.40% increase with 25% Tmean, Rs, VPD, U2, respectively. Simulating indicated 2.5 °C rise offset doubling concentration. Thus, rising moderated increasing concentrations, demand may not significantly change