Assimilation of spatially distributed water levels into a shallow-water flood model. Part II: Use of a remote sensing image of Mosel River

JOURNAL OF HYDROLOGY

卷:390

Article

Hostache, Renaud³  Lai, Xijun⁴  Monnier, Jerome^1,2  Puech, Christian³ 

[1] INP Grenoble, F-38041 Grenoble 9, France

[2] INRIA, Lab LJK, F-38041 Grenoble 9, France

[3] Cemagref, UMR TETIS, F-34093 Montpellier 5, France

[4] Chinese Acad Sci, Nanjing Inst Geog & Limnol, State Key Lab Lake Sci & Environm, Nanjing 210008, Peoples R China

关键词: Hydraulic modelling;    Roughness parameters;    Satellite SAR images;    Digital Elevation Model;    Variational data assimilation;    Hydraulic coherence;   

DOI  :  10.1016/j.jhydrol.2010.07.003

来源: Elsevier

【 摘 要 】

With rapid flood extent mapping capabilities, Synthetic Aperture Radar (SAR) images of river inundation prove to be very relevant to operational flood management. In this context, a recently developed method provides distributed water levels from SAR images. Furthermore, in view of improving numerical flood prediction, a variational data assimilation method (40-var) using such distributed water level has been developed in Part I of this study. This method combines an optimal sense remote sensing data (distributed water levels extracted from spatial images) and a 2D shallow water model. In the present article (Part-II of the study), we also derive water levels with a 40 cm average vertical uncertainty from a RADARSAT-1 image of a Mosel River flood event (1997, France). Assimilated in a 2D shallow water hydraulic model using the 4D-var developed method, these SAR derived spatially distributed water levels prove to be capable of enhancing model calibration. Indeed, the assimilation process can identify optimal Manning friction coefficients, at least in the river channel. Moreover, used as a guide for sensitivity analysis, remote sensing water levels allow also identifying some areas in the floodplain and the channel where Manning friction coefficients are homogeneous. This allows basing the spatial segmentation of roughness coefficient on floodplain hydraulic functioning. (C) 2010 Elsevier B.V. All rights reserved.

【 授权许可】

Free