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- Title
Implementation of Dynamic Effective Rooting Depth in Evapotranspiration Model Deepens Understanding of Evapotranspiration Partitioning Under Soil Moisture Gradients in China.
- Authors
Shao, Rui; Zhang, Baoqing; He, Xiaogang
- Abstract
Evapotranspiration (ET) is a key component of water cycle and is strongly modulated by below‐ground (e.g., dynamic effective rooting depth, Zr) and above‐ground (e.g., LAI and canopy height, CH) vegetation dynamics. Existing studies mainly focus on the effect of above‐ground vegetation dynamics on ET, while it is still unclear how Zr affects ET. Moreover, it is challenging to parameterize Zr dynamically in large‐scale hydrological and biogeochemical models due to data scarcity. Here, we estimate Zr in China from 1982 to 2015 based on Guswa's carbon cost‐benefit model, and update ET partitioning algorithm by replacing CH with Zr in PT‐JPLsm model to form the PT‐JPLzr model. We find that root mean square error (RMSE) between modeled (based on PT‐JPLzr model) and observed ET is 8.25% lower than that of PT‐JPLsm model at 16 in‐situ ET observation sites. Comparing with T/ET from the satellite‐based products, our results highlight the improved performance of PT‐JPLzr (R2 = 0.66) due to incorporated Zr, which is superior to that of PT‐JPLsm model (R2 = 0.62). Transpiration (T) limited by changes in soil moisture (SM) is more sensitive to Zr than CH. Thus, Zr improves the PT‐JPL model performance by affecting the sensitivity of T to soil moisture deficit. Moreover, SM and LAI are main drivers of T/ET spatial variability in drier and wetter regions, respectively. These findings highlight the critical role of Zr in regulating the effects of soil moisture deficit on ET. Key Points: We extend the static plant rooting depth to estimate the dynamic effective rooting depth (Zr) across ChinaZr is incorporated into evapotranspiration (ET) model to simultaneously consider the joint effects of canopy structure and rooting depth on ETTranspiration limited by soil moisture deficit is more sensitive to changes in Zr than canopy height (CH)
- Subjects
CHINA; SOIL moisture; EVAPOTRANSPIRATION; DEFICIT irrigation; STANDARD deviations; VEGETATION dynamics; PARALLEL algorithms; HYDROLOGIC cycle
- Publication
Water Resources Research, 2022, Vol 58, Issue 11, p1
- ISSN
0043-1397
- Publication type
Article
- DOI
10.1029/2022WR032962