Inner Mongolia Agricultural University Water Conservancy and Civil Engineering College, 010018 Hohhot, China; Inner Mongolia Water Resource Protection and Utilization Key Laboratory, 010018 Hohhot, China.
Inner Mongolia Agricultural University Water Conservancy and Civil Engineering College, 010018 Hohhot, China; Inner Mongolia Water Resource Protection and Utilization Key Laboratory, 010018 Hohhot, China.
Sci Total Environ. 2022 Jan 1;802:149937. doi: 10.1016/j.scitotenv.2021.149937. Epub 2021 Aug 26.
The accurate simulation of stomatal conductance is crucial for not only revealing the carbon and water cycle processes of an ecosystem, but also to improve the accuracy of simulations of evapotranspiration (ET). This study coupled three stomatal conductance models, i.e. the Stannard (ST), Jarvis-Stewart (JS), and Ball-Berry (BB) models, with the Shuttleworth-Wallace (SW) model to estimate ET for a mobile dune ecosystem in the Horqin Sandy Land, North China. These models were calibrated and validated using eddy covariance (EC) measurements taken during the growing season between 2013 and 2018. The results indicated that the SW-BB model showed better performance in comparison to the SW-JS and SW-ST models at half-hourly and daily timescales. The stomatal conductance models incorporating soil moisture (SM) content generally showed better performance during the extreme drought period, with the rank of the three models according to performance being: SW-BB > SW-JS > SW-ST. The models showed the highest sensitivity to SM when incorporating the effect of SM on stomatal conductance, indicating that SM has an important effect on stomatal conductance and ET. The results of this study indicate that of the models assessed, the Ball-Berry stomatal conductance model coupled with the SW model is optimal for estimating ET in dune ecosystems with sparse vegetation.
准确模拟气孔导度不仅对于揭示生态系统的碳和水循环过程至关重要，而且对于提高蒸散（ET）模拟的准确性也至关重要。本研究将三种气孔导度模型（即 Stannard（ST）、Jarvis-Stewart（JS）和 Ball-Berry（BB）模型）与 Shuttleworth-Wallace（SW）模型耦合，用于估算中国北方科尔沁沙地移动沙丘生态系统的蒸散量。这些模型使用 2013 年至 2018 年生长季期间的涡度相关（EC）测量数据进行了校准和验证。结果表明，与 SW-JS 和 SW-ST 模型相比，SW-BB 模型在半小时和日尺度上的表现更好。在极端干旱时期，包含土壤水分（SM）含量的气孔导度模型通常表现更好，根据性能对三个模型进行的排名为：SW-BB>SW-JS>SW-ST。这些模型在包含 SM 对气孔导度的影响时对 SM 表现出最高的敏感性，这表明 SM 对气孔导度和 ET 有重要影响。本研究结果表明，在所评估的模型中，将 Ball-Berry 气孔导度模型与 SW 模型耦合是估算植被稀疏沙丘生态系统 ET 的最佳选择。
