1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model
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 topogr...
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ftdoajarticles:oai:doaj.org/article:a5a2fb91dbf14be985a5197390b91f01 2023-05-15T18:32:31+02:00 1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model X. V. Phan L. Ferro-Famil M. Gay Y. Durand M. Dumont S. Morin S. Allain G. D'Urso A. Girard 2014-10-01T00:00:00Z https://doi.org/10.5194/tc-8-1975-2014 https://doaj.org/article/a5a2fb91dbf14be985a5197390b91f01 EN eng Copernicus Publications http://www.the-cryosphere.net/8/1975/2014/tc-8-1975-2014.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-8-1975-2014 https://doaj.org/article/a5a2fb91dbf14be985a5197390b91f01 The Cryosphere, Vol 8, Iss 5, Pp 1975-1987 (2014) Environmental sciences GE1-350 Geology QE1-996.5 article 2014 ftdoajarticles https://doi.org/10.5194/tc-8-1975-2014 2022-12-31T01:11:50Z 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 ... Article in Journal/Newspaper The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 8 5 1975 1987 |
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Directory of Open Access Journals: DOAJ Articles |
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language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
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Environmental sciences GE1-350 Geology QE1-996.5 X. V. Phan L. Ferro-Famil M. Gay Y. Durand M. Dumont S. Morin S. Allain G. D'Urso A. Girard 1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
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 ... |
format |
Article in Journal/Newspaper |
author |
X. V. Phan L. Ferro-Famil M. Gay Y. Durand M. Dumont S. Morin S. Allain G. D'Urso A. Girard |
author_facet |
X. V. Phan L. Ferro-Famil M. Gay Y. Durand M. Dumont S. Morin S. Allain G. D'Urso A. Girard |
author_sort |
X. V. Phan |
title |
1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model |
title_short |
1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model |
title_full |
1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model |
title_fullStr |
1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model |
title_full_unstemmed |
1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model |
title_sort |
1d-var multilayer assimilation of x-band sar data into a detailed snowpack model |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/tc-8-1975-2014 https://doaj.org/article/a5a2fb91dbf14be985a5197390b91f01 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 8, Iss 5, Pp 1975-1987 (2014) |
op_relation |
http://www.the-cryosphere.net/8/1975/2014/tc-8-1975-2014.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-8-1975-2014 https://doaj.org/article/a5a2fb91dbf14be985a5197390b91f01 |
op_doi |
https://doi.org/10.5194/tc-8-1975-2014 |
container_title |
The Cryosphere |
container_volume |
8 |
container_issue |
5 |
container_start_page |
1975 |
op_container_end_page |
1987 |
_version_ |
1766216629678505984 |