气候变化领域集成服务门户(CCPortal): Monitoring of wheat crops using the backscattering coefficient and the interferometric coherence derived from Sentinel-1 in semi-arid areas

CCPortal

DOI	10.1016/j.rse.2020.112050
	Monitoring of wheat crops using the backscattering coefficient and the interferometric coherence derived from Sentinel-1 in semi-arid areas
	Ouaadi N.; Jarlan L.; Ezzahar J.; Zribi M.; Khabba S.; Bouras E.; Bousbih S.; Frison P.-L.
发表日期	2020
ISSN	00344257
卷号	251
英文摘要	Radar data at C-band has shown great potential for the monitoring of soil and canopy hydric conditions of wheat crops. In this study, the C-band Sentinel-1 time series including the backscattering coefficients σ0 at VV and VH polarization, the polarization ratio (PR) and the interferometric coherence ρ are first analyzed with the support of experimental data gathered on three plots of irrigated winter wheat located in the Haouz plain in the center of Morocco covering five growing seasons. The results showed that ρ and PR are tightly related to the canopy development. ρ is also sensitive to soil preparation. By contrast, σ0 was found to be widely linked to changes in surface soil moisture (SSM) during the first growth stages when Leaf Area Index remains moderate (<1.5 m2/m2). In addition, drastic changes in the crop geometry associated to heading had a strong impact on the C-band σ0, in particular for VH polarization. The coupled water cloud and Oh models (WCM) were then calibrated and validated on the study sites. The comparison between the predicted and observed σ0 yielded a root mean square error (RMSE) values ranging from 1.50 dB to 2.02 dB for VV and between 1.74 dB to 2.52 dB for VH with significant differences occurring in the second part of the season after heading. Finally, new approaches based on the inversion of the WCM for SSM retrieval over wheat fields were proposed using Sentinel-1 radar data only. To this objective, the dry above-ground biomass (AGB) and the vegetation water content (VWC) were retrieved from the interferometric coherence and the PR. The relationships were then used as the vegetation descriptor in the WCM. The best retrieval results were obtained using the relationship between ρVV and the AGB (R and RMSE of 0.82, 0.05 m3/m3 respectively and no bias). The new retrieval approaches were then applied to a large database covering a rainfed field in Morocco and 18 plots of rainfed and irrigated wheat of the Kairouan plain (Tunisia) and compared to other classical techniques of SSM retrieval including simple linear relationships between SSM and σ0. The method based on the WCM and the ρVV-AGB relationships also provided with slightly better results than the others on the validation database (r = 0.75, RMSE = 0.06 m3/m3 and bias = 0.01 m3/m3 over the 18 plots of Tunisia) but the simple linear relationships performed also reasonably well (r = 0.62, RMSE = 0.07, bias = −0.01 in Tunisia for instance). This study opens perspectives for high resolution soil moisture mapping from Sentinel-1 data over south Mediterranean wheat crops and in fine, for irrigation scheduling and retrieval through the assimilation of these new products in an evapotranspiration model. © 2020 Elsevier Inc.
英文关键词	Backscattering coefficient; C-band; Interferometric coherence; Semi-arid region; Sentinel-1; Surface soil moisture; Winter wheat
语种	英语
scopus关键词	Crops; Interferometry; Mean square error; Polarization; Radar; Soil moisture; Vegetation; Backscattering coefficients; Evapotranspiration modeling; Interferometric coherence; Irrigation scheduling; Root mean square errors; Simple linear relationship; Soil moisture mapping; Vegetation water contents (VWC); Backscattering; aboveground biomass; backscatter; data assimilation; evapotranspiration; geometry; model validation; rainfed agriculture; satellite data; semiarid region; Sentinel; vegetation mapping; water content; wheat; Kairouan; Morocco; Tunisia; Triticum aestivum
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/179137
作者单位	LMFE, Department of Physics, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco; CESBIO, University of Toulouse, IRD/CNRS/UPS/CNES, Toulouse, France; MISCOM, National School of Applied Sciences, Cadi Ayyad University, Safi, Morocco; CRSA, Mohammed VI Polytechnic University UM6P, Ben Guerir, Morocco; ProcEDE, Department of Applied Physique, Faculty of Sciences and Technologies, Cadi Ayyad University, Marrakech, Morocco; INAT, GREEN-TEAM, Tunis, Tunisia; LaSTIG/MATWAS, IGN, University of Paris-Est, Champs sur Marne, Paris, France
推荐引用方式 GB/T 7714	Ouaadi N.,Jarlan L.,Ezzahar J.,et al. Monitoring of wheat crops using the backscattering coefficient and the interferometric coherence derived from Sentinel-1 in semi-arid areas[J],2020,251.
APA	Ouaadi N..,Jarlan L..,Ezzahar J..,Zribi M..,Khabba S..,...&Frison P.-L..(2020).Monitoring of wheat crops using the backscattering coefficient and the interferometric coherence derived from Sentinel-1 in semi-arid areas.Remote Sensing of Environment,251.
MLA	Ouaadi N.,et al."Monitoring of wheat crops using the backscattering coefficient and the interferometric coherence derived from Sentinel-1 in semi-arid areas".Remote Sensing of Environment 251(2020).