Comparison of the Effectiveness of Two Budyko-Based Methods for Actual Evapotranspiration in Uttar Pradesh, India

Abstract

Evapotranspiration is an important indicator in hydrology, agriculture, and climate. The classical methods to compute the evapotranspiration incorporate climate data of temperature and precipitation. Thornthwaite and Budyko approaches, therefore called here TBA, are the most applied methods for monthly potential evapotranspiration (ET0) respective actual evapotranspiration (AET0). In this study, we have compared the differences between ET0 and AET0 carried out with TBA methods with the crop evapotranspiration (ETc) and actual crop evapotranspiration (AETc) carried out with new methods of TBA applied at spatial scale (TBSS) including the land cover data. Mean monthly rainfall and mean monthly air temperature from 24 meteorological stations located in the Uttar Pradesh State from India were analyzed together with the land cover data to observe and analyse the spatial distributions and differences in evapotranspiration pattern. The study was conducted for 1951-2000 period including seasonal analysis. The results indicates that during the midseason, the ET0 reaches highest values (856.25 mm) while in the same period, the ETc indicates values about 1343.44 mm. The differences between seasonal ET0 and ETc were observed also for the initial and end seasons, with significant increases in evapotranspiration (about 200 mm). Interestingly, during the cold season, the ET0 has higher values than ETc with about 20 mm. As consequences of seasonal increases of the ETc, the annual ETc and AETc indicate higher values than annual ET0 and AET0. These aspects may imply the reduction of runoff and water availability in the study area. Moreover, these findings highlight the importance of land cover pattern in the calculation of evapotranspiration and water balance. The results are illustrates that the applied methodology including the land cover data is more reliable for regional scale and water management investigation rather than the classic methods.

European Grid Dataset of Actual Evapotranspiration, Water Availability and Effective Precipitation

“…Secondly, the frame of the analysis provides 30-year averages, which is convenient for the evaluation of climate and water resources over several decades and to develop future perspectives and plans. Another limitation is related to the monthly ET0 calculated using the Thornthwaite method, which is based on the temperature and precipitations parameters [49,50]. In this approach, the wind speed, solar radiation, and humidity were not considered due to a lack of data and also due to the uncertainties that may appear if these data are projected for the future.…”