Sensitivity of reference evapotranspiration to weather variables across seven regions of Turkey

Daily weather data from 1984 to 2018 for 14 stations representing seven regions of Turkey were used estimate reference evapotranspiration (ETref). We performed sensitivity analyses input variables (air temperature, wind speed, and solar radiation) determine the relative effects measurement errors in on accuracy calculated grass (ETos) alfalfa (Medicago sativa L., ETrs) ET. In addition, changes estimated irrigation water requirement maize (Zea mays L.), a major crop all Turkey, due climatic also determined across Turkey. Comparison coefficients indicated that ETref was most sensitive speed (sensitivities −2.46 5.56 mm d–1), followed by air temperature −2.13 3.1 d–1) However, responses ETos ETrs varied regions. For examples, Marmara region had largest impact but smallest ETref. Likewise, Southeastern Eastern Anatolia greatest The led substantial over- or underestimation maize. some cases, overestimated more than double. These results suggest different sensor accuracies are needed accurately requirement.