气候变化领域集成服务门户(CCPortal): 1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model

CCPortal

DOI	10.5194/tc-8-1975-2014
	1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model
	Phan X.V.; Ferro-Famil L.; Gay M.; Durand Y.; Dumont M.; Morin S.; Allain S.; D'Urso G.; Girard A.
发表日期	2014
ISSN	19940416
卷号	8 期号:5
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).
学科领域	backscatter; data assimilation; data set; divergence; meteorology; numerical model; remote sensing; snow cover; snowpack; spatial resolution; synthetic aperture radar
语种	英语
scopus关键词	backscatter; data assimilation; data set; divergence; meteorology; numerical model; remote sensing; snow cover; snowpack; spatial resolution; synthetic aperture radar
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/120038
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
推荐引用方式 GB/T 7714	Phan X.V.,Ferro-Famil L.,Gay M.,et al. 1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model[J],2014,8(5).
APA	Phan X.V..,Ferro-Famil L..,Gay M..,Durand Y..,Dumont M..,...&Girard A..(2014).1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model.Cryosphere,8(5).
MLA	Phan X.V.,et al."1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model".Cryosphere 8.5(2014).