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Climatic Controls on Watershed Reference Evapotranspiration Varied during 1961–2012 in Southern China
Author(s) -
Qin Mengsheng,
Hao Lu,
Sun Lei,
Liu Yongqiang,
Sun Ge
Publication year - 2019
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/1752-1688.12714
Subject(s) - evapotranspiration , environmental science , hydrometeorology , vapour pressure deficit , relative humidity , climate change , wind speed , air temperature , hydrology (agriculture) , drainage basin , atmospheric sciences , subtropics , water resources , climatology , precipitation , geography , transpiration , meteorology , ecology , photosynthesis , botany , geotechnical engineering , cartography , geology , engineering , biology
Reference evapotranspiration (ET o ) is an important hydrometeorological term widely used in understanding and projecting the hydrological effects of future climate and land use change. We conducted a case study in the Qinhuai River Basin that is dominated by a humid subtropical climate and mixed land uses in southern China. Long‐term (1961–2012) meteorological data were used to estimate ET o by the FAO‐56 Penman–Monteith model. The individual contribution from each meteorological variable to the trend of ET o was quantified. We found basin‐wide annual ET o decreased significantly ( p < 0.05) by 3.82 mm/yr during 1961–1987, due to decreased wind speed, solar radiation, vapor pressure deficit (VPD), and increased relative humidity (RH). However, due to the increased VPD and decreased RH, the ET o increased significantly ( p < 0.05) in spring, autumn, and annually at a rate of 2.55, 0.56, and 3.16 mm/yr during 1988–2012, respectively. The aerodynamic term was a dominant factor controlling ET o variation in both two periods. We concluded the key climatic controls on ET o have shifted as a result of global climate change during 1961–2012. The atmospheric demand, instead of air temperature alone, was a major control on ET o . Models for accurately predicting ET o and hydrological change under a changing climate must include VPD in the study region. The shifts of climatic control on the hydrological cycles should be considered in future water resource management in humid regions.