Paper Info
Title
The Potential of ALOS-2 and Sentinel-1 Radar Data for Soil Moisture Retrieval With High Spatial Resolution Over Agroforestry Areas, China
Abstract
Synthetic aperture radar (SAR) sensors, such as Advanced Land Observing Satellite-2 (ALOS-2) and Sentinel-1, provide significant opportunities for soil moisture content (SMC) retrieval with relatively high spatial resolutions (10 similar to 30 m). In this work, an artificial neural network (ANN) SMC retrieval algorithm combined with the water cloud model, the advanced integral equation model, and the Oh model database was proposed. The SAR copolarization backscatter, the local incidence angle (ILIA), and the normalized difference vegetation index were used in input vectors for the ANN algorithm for the retrieval and mapping of the ALOS-2 and Sentinel-1 SMC at a 30-m resolution. The results of the comparison between the SMC retrievals and the measured SMC show that Sentinel-1 and ALOS-2 SMC retrievals with high accuracy correspond to low-vegetation areas (crop, grass, and shrub), with a root mean square error (RMSE) of 0.021 and 0.033 cm(3)/cm(3), respectively. ALOS-2 SMC retrievals provide higher accuracy (RMSE = 0.076 cm(3)/cm(3)) than Sentinel-1 SMC retrievals at high vegetation (e.g., forest). However, it remains challenging for soil moisture retrieval in forest land. The C-hand and L-band SMC retrievals have higher RMSE (up to 0.047 cm(3)/cm(3)) at low incidence angle (<20 degrees) and high incidence angle (>50 degrees). In addition, by considering the impact of rainfall on the SMC, it appears that the Sentinel-I and AIRS-2 SMC have a good response to the rainfall events. Finally, the results of the comparison between the SMC retrievals and the Soil Moisture Active Passive (SMAP) L2 SMC product show that the correlation coefficients between Sentinel-1, ALOS-2, and SMAP are higher in September when the vegetation is drying than in July when the vegetation is growing.
Year
DOI
Venue
2022
10.1109/TGRS.2021.3082805
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
Keywords
DocType
Volume
Advanced Land Observing Satellite-2 (ALOS-2), agroforestry area, artificial neural network (ANN), Sentinel-1, soil moisture content (SMC)
Journal
60
ISSN
Citations 
PageRank 
0196-2892
0
0.34
References 
Authors
0
8
Name
Order
Citations
PageRank
Huizhen Cui111.71
Lingmei Jiang2347.85
Simonetta Paloscia317936.14
Emanuele Santi400.34
Simone Pettinato500.34
Jian Wang67640.08
Xiyao Fang700.34
Wanjin Liao800.34