气候变化领域集成服务门户(CCPortal): Soil moisture retrievals using L-band radiometry from variable angular ground-based and airborne observations

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DOI	10.1016/j.rse.2020.111958
	Soil moisture retrievals using L-band radiometry from variable angular ground-based and airborne observations
	Zhao T.; Hu L.; Shi J.; Lü H.; Li S.; Fan D.; Wang P.; Geng D.; Kang C.S.; Zhang Z.
发表日期	2020
ISSN	00344257
卷号	248
英文摘要	Surface soil moisture is a vital variable in the process of energy exchange between the land and atmosphere. Monitoring the surface soil moisture at the local and global scales has become feasible due to the development of microwave remote sensing. With the new development of potential satellite missions, it is important to evaluate existing soil moisture retrieval algorithms, which will greatly contribute to the improvement of current soil moisture products and the development of new methodologies. This paper compared the performance of four well-known soil moisture retrieval algorithms with L-band radiometry at fixed incidence angles, including the single channel algorithm at horizontal polarization (SCA-H), the single channel algorithm at vertical polarization (SCA-V), the dual channel algorithm (DCA), and the land parameter retrieval model (LPRM). The experimental data used for evaluation was from the Soil Moisture Experiment in the Luan River (SMELR), which consists of variable angular ground-based and airborne observations covering a wide range of incidence angles (22.5°–55°) at L-band. The microwave radiative transfer models are set to be consistent to guarantee that the four different algorithms are comparable. The results showed that the retrieval accuracy of the SCA-H and SCA-V is significantly affected by the input vegetation optical depth, and the calibration of vegetation parameters should be considered in the implementation of the SCA-H and SCA-V. The DCA does not rely on the auxiliary vegetation information and can also achieve good performance for both the soil moisture and vegetation optical depth. However, its retrieval requires a penalty on parameter constraints since the input brightness temperatures at horizontal and vertical polarization are correlated. The LPRM has a poor performance at incidence angles less than 30°, as it analytically utilizes the polarization difference in the brightness temperature, which is quite small at lower incidence angles. The accuracy of four soil moisture algorithms achieve their best performances at intermediate incidence angles of 40° to 45°, and is slightly degraded when the incident angles increased to larger than 50°, which is contributed to the increasing vegetation effects and depolarization that leads to an information loss. These findings provide quantitative evidence to help understand the differences in various current soil moisture algorithms and further promote the development of new methodologies for future soil moisture missions. © 2020 Elsevier Inc.
英文关键词	Airborne experiment; Ground-based measurement; L-band radiometry; Soil moisture; Variable incidence angle
语种	英语
scopus关键词	Horizontal wells; Luminance; Polarization; Radiative transfer; Radiometry; Remote sensing; Temperature; Vegetation; Brightness temperatures; Horizontal and vertical polarizations; Horizontal polarization; Microwave radiative transfer model; Microwave remote sensing; Single-channel algorithms; Soil moisture retrievals; Vegetation optical depth; Soil moisture; airborne survey; algorithm; brightness temperature; calibration; polarization; radiative transfer; radiometric survey; soil moisture; vegetation structure; China; Luan River
来源期刊	Remote Sensing of Environment
来源机构	中国科学院西北生态环境资源研究院
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/179215
作者单位	State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, China; College of Hydrology and Water Resources, Hohai University, China; Unit 93920, China; College of Resources and Environment, University of Chinese Academy of Sciences, China; Shanghai Academy of Spaceflight Technology, China; Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, China
推荐引用方式 GB/T 7714	Zhao T.,Hu L.,Shi J.,et al. Soil moisture retrievals using L-band radiometry from variable angular ground-based and airborne observations[J]. 中国科学院西北生态环境资源研究院,2020,248.
APA	Zhao T..,Hu L..,Shi J..,Lü H..,Li S..,...&Zhang Z..(2020).Soil moisture retrievals using L-band radiometry from variable angular ground-based and airborne observations.Remote Sensing of Environment,248.
MLA	Zhao T.,et al."Soil moisture retrievals using L-band radiometry from variable angular ground-based and airborne observations".Remote Sensing of Environment 248(2020).