Dong Jianzhi, Akbar Ruzbeh, Short Gianotti Daniel J, Feldman Andrew F, Crow Wade T, Entekhabi Dara
Department of Civil and Environmental Engineering Massachusetts Institute of Technology Cambridge MA USA.
Institute of Surface-Earth System Science Tianjin University Tianjin China.
Geophys Res Lett. 2022 Apr 16;49(7):e2021GL097697. doi: 10.1029/2021GL097697. Epub 2022 Apr 5.
The transition of evapotranspiration between energy- and water-limitation regimes also denotes a nonlinear change in surface water and energy coupling strength. The regime transitions are primarily dominated by available moisture in the soil, although other micro-meteorological factors also play a role. Remotely sensed soil moisture is frequently used for detecting evapotranspiration regime transitions during inter storm dry downs. However, its sampling depth does not include the entire soil profile, over which water uptake is dominated by plant root distribution. We use flux tower, surface ( ; observations at 5 cm), and vertically integrated in situ soil moisture ( ; 0-50 cm) observations to address the question: Can surface soil moisture robustly identify evapotranspiration regime transitions? Results demonstrate that and are hydraulically linked and have synchronized evapotranspiration regime transitions. As such, and capture comparable statistics of evapotranspiration regime prevalence, which supports the utility of remote-sensing for large-scale land-atmosphere exchange analysis.
蒸发散在能量限制和水分限制状态之间的转变也意味着地表水与能量耦合强度的非线性变化。尽管其他微气象因素也起作用，但状态转变主要受土壤中有效水分的主导。在暴雨间期土壤变干期间，遥感土壤湿度经常被用于检测蒸发散状态转变。然而，其采样深度并不包括整个土壤剖面，而整个土壤剖面的水分吸收主要由植物根系分布主导。我们使用通量塔、地表（5厘米处的观测值）以及垂直积分原位土壤湿度（0 - 50厘米）观测值来解决这个问题：表层土壤湿度能否可靠地识别蒸发散状态转变？结果表明，两者在水力上是相连的，并且具有同步的蒸发散状态转变。因此，两者捕捉到了蒸发散状态普遍程度的可比统计数据，这支持了遥感土壤湿度在大规模陆 - 气交换分析中的实用性。
