气候变化领域集成服务门户(CCPortal): Validation and expansion of the soil moisture index for assessing soil moisture dynamics from AMSR2 brightness temperature

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DOI	10.1016/j.rse.2024.114018
	Validation and expansion of the soil moisture index for assessing soil moisture dynamics from AMSR2 brightness temperature
	Meng, Xiangjin; Hu, Jia; Peng, Jian; Li, Ji; Leng, Guoyong; Ferhatoglu, Caner; Li, Xueying; Garcia-Garcia, Almudena; Yang, Yingbao
发表日期	2024
ISSN	0034-4257
EISSN	1879-0704
起始页码	303
卷号	303
英文摘要	Long-term remotely sensed soil moisture (SM) data is essential for understanding the land-atmosphere hydrological and energy interactions at both local and global scales. Passive microwave SM retrieval remains challenging at the global scale, especially in areas with complex terrain conditions, due to the difficulties in acquiring accurate land surface parameters (e.g., vegetation and surface roughness) across large extents and the uncertainties caused by the assumptions associated with current retrieval algorithms. This study addresses these challenges by providing a comprehensive evaluation of satellite SM products and introducing Soil Moisture Index (SMI)-based indicators derived from Advanced Microwave Scanning Radiometer 2 (AMSR2) brightness temperature (TB). It is noteworthy that SMI, recently proposed and showing promising results in the low-frequency L-band, lacks validation for high-frequency microwave observations. This research fills this critical gap by evaluating the emissivity-based soil moisture index (ESMI) utilizing C- and X-band TB. To mitigate potential uncertainties in land surface temperature (LST) data used in emissivity-based methods, we propose an alternative brightness temperature-based soil moisture indicator (TBSMI). Simulation experiments demonstrated the effectiveness of TBSMI for capturing SM dynamics with a strong correlation coefficient of 0.95. TBSMI was then evaluated against in situ measurements from a total of 553 ground stations in 12 dense and 4 sparse SM networks worldwide under different climatic and environmental conditions from 1 April 2015 to 31 December 2017. Intercomparisons were also made with two widely used AMSR2 SM products [i.e., the land parameter retrieval model (LPRM) product, and the Japan Aerospace Exploration Agency (JAXA) product], as well as with the ESMI. The results suggested that TBSMI exhibited the best performance with a mean R of 0.65 against in situ observations, followed by ESMI (mean R of 0.58), while LPRM and JAXA achieved lower correlation with mean R of 0.52 and 0.41 respectively. Specifically, TBSMI and ESMI retained a robust capability in densely vegetated areas, where LPRM and JAXA deteriorated sharply. Moreover, TBSMI demonstrated stable performance across diverse conditions, providing an accurate and robust alternative for monitoring SM. Our study highlights the unique advantages of the SMI approach in capturing SM dynamics under complex land surface conditions, and can be useful for diverse hydrological applications and climate change studies.
英文关键词	Soil moisture index; Brightness temperature; Land surface temperature; Diverse ground conditions; AMSR2
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Remote Sensing ; Imaging Science & Photographic Technology
WOS类目	Environmental Sciences ; Remote Sensing ; Imaging Science & Photographic Technology
WOS记录号	WOS:001181663100001
来源期刊	REMOTE SENSING OF ENVIRONMENT
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/305939
作者单位	Hohai University; Helmholtz Association; Helmholtz Center for Environmental Research (UFZ); Leipzig University; Chinese Academy of Sciences; Institute of Geographic Sciences & Natural Resources Research, CAS; Hohai University
推荐引用方式 GB/T 7714	Meng, Xiangjin,Hu, Jia,Peng, Jian,et al. Validation and expansion of the soil moisture index for assessing soil moisture dynamics from AMSR2 brightness temperature[J],2024,303.
APA	Meng, Xiangjin.,Hu, Jia.,Peng, Jian.,Li, Ji.,Leng, Guoyong.,...&Yang, Yingbao.(2024).Validation and expansion of the soil moisture index for assessing soil moisture dynamics from AMSR2 brightness temperature.REMOTE SENSING OF ENVIRONMENT,303.
MLA	Meng, Xiangjin,et al."Validation and expansion of the soil moisture index for assessing soil moisture dynamics from AMSR2 brightness temperature".REMOTE SENSING OF ENVIRONMENT 303(2024).