The Tibetan Plateau is generally referred to as the Chinese water tower,and evapotranspiration(ET)affects the water budget and stability of alpine meadows on the Tibetan Plateau.However,its variability and controlling...The Tibetan Plateau is generally referred to as the Chinese water tower,and evapotranspiration(ET)affects the water budget and stability of alpine meadows on the Tibetan Plateau.However,its variability and controlling mechanisms have not been well documented under the drier conditions induced by global warming.Therefore,this study aimed to clarify whether meteorological or biological factors primarily affected the variability in ET under contrasting water conditions in the alpine meadow ecosystem on the Tibetan Plateau.Based on 6-year(2013-2018)eddy covariance observations and the corresponding meteorological and biological data,linear perturbation analyses were employed to isolate the contributions of meteorological and biological factors to the variability in evapotranspiration(SET).The results showed that ET was mainly driven by meteorological factors in wet peak seasons(July and August),and was dominated by net radiation(Rn)and air temperature(Ta),indicating that the inadequate available energy is the factor limiting ET.However,the dominant factors affecting SET shifted from meteorological to biological in dry peak seasons when the canopy stomatal conductance(gs)and leaf area index were dominant.At this point,the ecosystem was limited by the water conditions.These results provide empirical insights into how meteorological and biological factors regulate variability in ET under contrasting water conditions.These findings can further improve our understanding of water cycle processes and can help effectively manage water resources in alpine meadow ecosystems under future climate change conditions.展开更多
基金the National Natural ScienceFoundationof China(41725003,31600362 and 32061143037)the National Key Research and Development Program of China(2017YFA0604801)the China Postdoctoral Science Foundation funded project(2021M692230 and 2018M631819)。
文摘The Tibetan Plateau is generally referred to as the Chinese water tower,and evapotranspiration(ET)affects the water budget and stability of alpine meadows on the Tibetan Plateau.However,its variability and controlling mechanisms have not been well documented under the drier conditions induced by global warming.Therefore,this study aimed to clarify whether meteorological or biological factors primarily affected the variability in ET under contrasting water conditions in the alpine meadow ecosystem on the Tibetan Plateau.Based on 6-year(2013-2018)eddy covariance observations and the corresponding meteorological and biological data,linear perturbation analyses were employed to isolate the contributions of meteorological and biological factors to the variability in evapotranspiration(SET).The results showed that ET was mainly driven by meteorological factors in wet peak seasons(July and August),and was dominated by net radiation(Rn)and air temperature(Ta),indicating that the inadequate available energy is the factor limiting ET.However,the dominant factors affecting SET shifted from meteorological to biological in dry peak seasons when the canopy stomatal conductance(gs)and leaf area index were dominant.At this point,the ecosystem was limited by the water conditions.These results provide empirical insights into how meteorological and biological factors regulate variability in ET under contrasting water conditions.These findings can further improve our understanding of water cycle processes and can help effectively manage water resources in alpine meadow ecosystems under future climate change conditions.
