Effects of clouds and aerosols on ecosystem exchange, water and light use efficiency in a humid region orchard

文献类型： 外文期刊

第一作者： Jiang, Shouzheng

作者： Jiang, Shouzheng;Huang, Yaowei;Zhao, Lu;Cui, Ningbo;Zheng, Shunsheng;Zou, Qingyao;Guo, Li;Cui, Ningbo;Hu, Xiaotao;Wang, Yaosheng;Feng, Yu

作者机构：

关键词： Clouds and aerosols; Evapotranspiration; Canopy transpiration; Gross primary productivity; Ecosystem light use efficiency; Ecosystem water use efficiency

期刊名称：SCIENCE OF THE TOTAL ENVIRONMENT （ 影响因子：10.753； 五年影响因子：10.237 ）

ISSN： 0048-9697

年卷期： 2022 年 811 卷

页码：

收录情况： SCI

摘要： Investigating the patterns of water and carbon dynamics in agro-ecosystems in response to clouds and aerosols can shed new insights in understanding the biophysical impacts of climate change on crop productivity and water consumption. In this study, the effects of clouds and aerosols as well as other environmental factors on ecosystem water and carbon fluxes were examined based on three-year eddy covariance measurements under different sky conditions (quantified as the clearness index, K-t, i.e., the ratio of global solar radiation to extraterrestrial solar radiation) in a kiwifruit plantation in the humid Sichuan Basin of China. Results showed that evapotranspiration (ET) and canopy transpiration (T-c, measured by sap flow sensors) increased, while ecosystem light use efficiency (eLUE) and ecosystem water use efficiency (eWUE) decreased with increasing K-t. GPP presented a parabolic relationship with increasing K-t. The path analysis revealed that surface conductance (G(s)) and canopy conductance (G(c)) were the most dominant variables directly regulated carbon (GPP) and water (ET and T-c) fluxes. The effect path of K-t on FT and T-c was converted from through diffuse photosynthetic active radiation (PAR(diff)) to direct PAR (PAR(dir)) when the sky became clearer. The effect path of K, on GPP was primarily through PAR th r under different sky conditions. The declined eWL1F. with increasing K, was caused by the different responses of GPP and FT to PAR(dir) under clear skies. The declined el.UF resulted from the sharp decrease in GPP/PAR(dir), which surpassed the slight increase of GPP/PAR(dif) with increasing PAR. The Priestley-Taylor Jet Propulsion laboratory ET model (PT-JPL) incorporating K-t with an exponential function produced more reliable T-c estimates but minor improvement in FT. Further, the LUE-GPP model incorporating K-t with a linear function obtained much better GPP estimates. Our study shed light on how sky conditions modulate water and carbon dynamics between the biosphere and atmosphere, highlighting the necessity of the inclusion of sky conditions for better modeling regional water and carbon budgets.

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