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Attribution analysis of actual and potential evapotranspiration changes based on the complementary relationship theory in the Huai River basin of eastern China
Author(s) -
Chu Ronghao,
Li Meng,
Islam Abu Reza Md. Towfiqul,
Fei Dunyue,
Shen Shuanghe
Publication year - 2019
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.6060
Subject(s) - evapotranspiration , environmental science , eddy covariance , climatology , wind speed , relative humidity , atmospheric sciences , advection , geography , meteorology , ecosystem , geology , ecology , physics , biology , thermodynamics
Accurate terrestrial evapotranspiration (ET) estimation and understanding the causes of ET variation are essential for water resource management and irrigation planning. In this research, the complementary relationship (CR) between actual evapotranspiration (ET a ) and potential evapotranspiration (ET p ) was evaluated. An Advection–Aridity (AA) model was calibrated and validated using eddy covariance measurements. The spatiotemporal variations of ET a , ET p and associated meteorological variables were examined through Mann–Kendall (MK) testing and Theil–Sen's estimator, using daily weather data from 137 meteorological stations in Huai River basin (HRB) during 1961–2014. Moreover, the influences of meteorological factors on ET a and ET p were quantified by the differential equation method. The results indicate that CR theory is applicable in the HRB and the calibrated AA model can simulate the ET a well. ET a exhibited a significant increasing trend before 1990 and then decreased significantly. However, ET p decreased significantly before 1990 and then declined slightly. During 1961–1990, except for significant increasing relative humidity (RH), other meteorological variables exhibited decreasing trends. The aerodynamic component dominated ET a and ET p trends in general. The wind speed at 2‐m height ( u 2 ) dominated ET a trends except for summer and growing season and ET p trends except for summer, when the dominant factor is net radiation ( R n ). During 1991–2014, mean temperature ( T a ) and RH showed distinct increasing and decreasing trends, respectively, whereas significant decline in u 2 palpably slowed. The absolute value of the radiative component was larger than that of the aerodynamic one. The dominant factor of ET a trends shifted from u 2 to RH in spring and to R n in autumn, winter and annual timescales. Moreover, the dominant factor of ET p trends changed from u 2 to RH in spring, winter and annual timescales and to R n in growing season and autumn. R n always played a pivotal role in both ET a and ET p trends in summer.