DOI: 10.5194/tc-8-1975-2014
Scopus记录号: 2-s2.0-84908244377
论文题名: 1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model
作者: Phan X ; V ; , Ferro-Famil L ; , Gay M ; , Durand Y ; , Dumont M ; , Morin S ; , Allain S ; , D'Urso G ; , Girard A
刊名: Cryosphere
ISSN: 19940416
出版年: 2014
卷: 8, 期: 5 起始页码: 1975
结束页码: 1987
语种: 英语
英文关键词: backscatter
; data assimilation
; data set
; divergence
; meteorology
; numerical model
; remote sensing
; snow cover
; snowpack
; spatial resolution
; synthetic aperture radar
英文摘要: The structure and physical properties of a snowpack and their temporal evolution may be simulated using meteorological data and a snow metamorphism model. Such an approach may meet limitations related to potential divergences and accumulated errors, to a limited spatial resolution, to wind or topography-induced local modulations of the physical properties of a snow cover, etc. Exogenous data are then required in order to constrain the simulator and improve its performance over time. Synthetic-aperture radars (SARs) and, in particular, recent sensors provide reflectivity maps of snow-covered environments with high temporal and spatial resolutions. The radiometric properties of a snowpack measured at sufficiently high carrier frequencies are known to be tightly related to some of its main physical parameters, like its depth, snow grain size and density. SAR acquisitions may then be used, together with an electromagnetic backscattering model (EBM) able to simulate the reflectivity of a snowpack from a set of physical descriptors, in order to constrain a physical snowpack model. In this study, we introduce a variational data assimilation scheme coupling TerraSAR-X radiometric data into the snowpack evolution model Crocus. The physical properties of a snowpack, such as snow density and optical diameter of each layer, are simulated by Crocus, fed by the local reanalysis of meteorological data (SAFRAN) at a French Alpine location. These snowpack properties are used as inputs of an EBM based on dense media radiative transfer (DMRT) theory, which simulates the total backscattering coefficient of a dry snow medium at X and higher frequency bands. After evaluating the sensitivity of the EBM to snowpack parameters, a 1D-Var data assimilation scheme is implemented in order to minimize the discrepancies between EBM simulations and observations obtained from TerraSAR-X acquisitions by modifying the physical parameters of the Crocus-simulated snowpack. The algorithm then re-initializes Crocus with the modified snowpack physical parameters, allowing it to continue the simulation of snowpack evolution, with adjustments based on remote sensing information. This method is evaluated using multi-temporal TerraSAR-X images acquired over the specific site of the Argentière glacier (Mont-Blanc massif, French Alps) to constrain the evolution of Crocus. Results indicate that X-band SAR data can be taken into account to modify the evolution of snowpack simulated by Crocus. © 2014 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/74773
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Grenoble Image Parole Signal et Automatique Lab, Grenoble, France; Institut d'Electronique et de Télécommunications de Rennes, University of Rennes, Rennes, France; Météo-France Andndash; CNRS, CNRM-GAME Andndash; UMR3589, Centre d'Etudes de la Neige, Grenoble, France; Electricité de France, Paris, France
Recommended Citation:
Phan X,V,, Ferro-Famil L,et al. 1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model[J]. Cryosphere,2014-01-01,8(5)