Effect of projected climate change on potential evapotranspiration in the semiarid region of central India

The performance of potential evapotranspiration (PET) methods such as pan evaporation (physical measurement), empirical formulas (Penman–Monteith (PM), Hargreaves and Thornthwaite) and satellite-derived PET (MOD16) were assessed in a semiarid region of central India. The satellite-based PET was obtained from Moderate Resolution Imaging Spectroradiometer (MODIS). The comparisons between different methods were made with observed pan evaporation (ETpan) data to identify the best method for the semiarid region. Further, the future projection of PET was carried out using RCP4.5 emission scenarios of seven CMIP5 models. Two approaches were applied for the projection of PET. In the first approach, RCP4.5 scenario data are directly used in the PM method, and in the second approach, these variables are used as a predictor in the calibrated and validated least square support vector machine (LS-SVM) model. The projection of PET was made using the best-identified model among PM and LS-SVM from the years 2006–2100. The results show that MOD16 and Hargreaves overestimate the PET; however, PM and Thornwaite underestimate the PET. PM based PET is closely related with ETpan and is a good indicator of ETpan in a semiarid region. GFDL-ESM2M is identified as the most skillful CMIP5 model, and results show that PET is projected to increase in future using the LS-SVM model. HIGHLIGHTS The PET estimation methods, namely empirical and satellite-based PET, were evaluated and compared with ground-based observed ET.; Satellite-based PET is closely matching with ground-based PET in wet season.; Satellite-based PET can be used after applying a suitable correction factor in the study area.; The PM method was found suitable for the semiarid region.; PET is projected to increase in future using CMIP5 models.