Evaluating effects of Dielectric Models on the surface soil moisture retrieval in the Qinghai-Tibet Plateau

• 来源期刊: 寒旱区科学（英文版）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: Articles
• 页码范围: 62-76
• 页数: 15页
• 语种: 英文

摘要

Based on the measurement of L-band ground-based microwave radiometer (ELBARA-Ⅲ type) in the Qinghai-Tibet Pla-teau and theτ- ω radiative transfer model, this research evaluated the effects of four soil dielectric models, i. e., Wang-Schmugge, Mironov, Dobson, and Four-phase, on the L-band microwave brightness temperature simulation and soil mois-ture retrieval. The results show that with the same vegetation and roughness parameterization scheme, the four soil dielec-tric models display obvious differences in microwave brightness temperature simulation. When the soil moisture is less than 0.23 m3/m3, the simulated microwave brightness temperature in Wang-Schmugge model is significantly different from that of the other three models, with maximum differences of horizontal polarization and vertical polarization reaching 8.0 K and 4.4 K, respectively;when the soil moisture is greater than 0.23 m3/m3, the simulated microwave brightness tempera-ture of Four-phase significantly exceeds that of the other three models;when the soil moisture is saturated, maximum dif-ferences in simulated microwave brightness temperature with horizontal polarization and vertical polarization are 6.1 K and 4.8 K respectively, and the four soil dielectric models are more variable in the microwave brightness temperature sim-ulation with horizontal polarization than that with vertical polarization. As for the soil moisture retrieval based on the four dielectric models, the comparison study shows that, under the condition of horizontal polarization, Wang-Schmugge mod-el can reduce the degree of retrieved soil moisture underestimating the observed soil moisture more effectively than other parameterization schemes, while under the condition of vertical polarization, the Mironov model can reduce the degree of retrieved soil moisture overestimating the observed soil moisture. Finally, based on the Wang-Schmugge model and FengYun-3C observation data, the spatial distribution of soil moisture in the study area is retrieved.