Agricultural Water Management ( IF 6.7 ) Pub Date : 2022-05-17 , DOI: 10.1016/j.agwat.2022.107706 Jie Wu, Yu Feng, Lili Liang, Xinyue He, Zhenzhong Zeng
Crop water use (also know as evapotranspiraton, ET) monitoring is vital for agricultural management under the threat of water scarcity and global warming, as well as the pressure of increasing food demand. The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) has provided valuable high-resolution ET estimates since its launch in 2018. Yet, evaluation of its capability in monitoring ET in the agricultural field is lacking, as well as the intercomparison of the two ECOSTRESS ET products calculated through different algorithms (PT-JPL vs. DisALEXI). This study focused on the agroecosystems and compared the ECOSTRESS ET to eddy covariance observations at 15 cropland flux sites in North America from July 2018 to December 2020. It is found that PT-JPL captured the diurnal pattern but tended to overestimate instantaneous ET in the morning. Besides, intercomparison of the magnitude, seasonal pattern and the dependency on crop phenology of ET from PT-JPL and DisALEXI revealed the higher fidelity of DisALEXI. The site-specific validations and visual comparisons with MODIS ET retrievals demonstrated the capability of PT-JPL and DisALEXI in identifying crop types and agricultural management practices to some extent. The heterogeneity of ET values in the small-scale agroecosystems highlights the importance of accurate representation of local conditions in the ET model.
中文翻译:
使用农业生态系统中的通量测量评估从 ECOSTRESS 观察到的蒸散
在水资源短缺和全球变暖的威胁以及粮食需求增加的压力下,作物用水(也称为蒸散量,ET)监测对于农业管理至关重要。自 2018 年启动以来,ECOsystem 空间站星载热辐射计实验 (ECOSTRESS) 提供了有价值的高分辨率 ET 估计。然而,缺乏对其在农业领域监测 ET 能力的评估,以及两者的相互比较通过不同算法计算的 ECOSTRESS ET 产品(PT-JPL 与 DisALEXI)。本研究侧重于农业生态系统并将 ECOSTRESS ET 与 2018 年 7 月至 2020 年 12 月北美 15 个农田通量站点的涡度协方差观测值进行了比较。发现 PT-JPL 捕获了昼夜模式,但倾向于高估早晨的瞬时 ET。此外, PT-JPL 和 DisALEXI 对 ET的量级、季节模式和对作物物候的依赖性的比对表明 DisALEXI 具有更高的保真度。特定地点的验证和与 MODIS ET 检索的视觉比较在一定程度上证明了 PT-JPL 和 DisALEXI 在识别作物类型和农业管理实践方面的能力。小规模农业生态系统中 ET 值的异质性突出了在 ET 模型中准确表示当地条件的重要性。