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| Titel |
On the assimilation of SWOT type data into 2D shallow-water models |
| VerfasserIn |
Frederic Couderc, Denis Dartus, Pierre-André Garambois, Madec Ronan, Jérôme Monnier, Jean-Paul Villa |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072617
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| Zusammenfassung |
| In river hydraulics, assimilation of water level measurements at gauging stations is well
controlled, while assimilation of images is still delicate. In the present talk, we address the
richness of satellite mapped information to constrain a 2D shallow-water model, but also
related difficulties. 2D shallow models may be necessary for small scale modelling in
particular for low-water and flood plain flows. Since in both cases, the dynamics of the
wet-dry front is essential, one has to elaborate robust and accurate solvers. In this contribution
we introduce robust second order, stable finite volume scheme [CoMaMoViDaLa].
Comparisons of real like tests cases with more classical solvers highlight the importance of
an accurate flood plain modelling. A preliminary inverse study is presented in a flood plain
flow case, [LaMo] [HoLaMoPu]. As a first step, a 0th order data processing model improves
observation operator and produces more reliable water level derived from rough
measurements [PuRa]. Then, both model and flow behaviours can be better understood
thanks to variational sensitivities based on a gradient computation and adjoint equations. It
can reveal several difficulties that a model designer has to tackle. Next, a 4D-Var data
assimilation algorithm used with spatialized data leads to improved model calibration and
potentially leads to identify river discharges. All the algorithms are implemented into
DassFlow software (Fortran, MPI, adjoint) [Da]. All these results and experiments
(accurate wet-dry front dynamics, sensitivities analysis, identification of discharges and
calibration of model) are currently performed in view to use data from the future SWOT
mission.
[CoMaMoViDaLa] F. Couderc, R. Madec, J. Monnier, J.-P. Vila, D. Dartus, K. Larnier.
“Sensitivity analysis and variational data assimilation for geophysical shallow water flows”.
Submitted.
[Da] DassFlow - Data Assimilation for Free Surface Flows. Computational
software
http://www-gmm.insa-toulouse.fr/~monnier/DassFlow/
[HoLaMoPu] R. Hostache, X. Lai, J. Monnier, C. Puech. “Assimilation of spatial
distributed water levels into a shallow-water flood model. Part II: using a remote sensing
image of Mosel river”. J. Hydrology (2010).
[LaMo] X. Lai, J. Monnier. “Assimilation of spatial distributed water levels into a
shallow-water flood model. Part I: mathematical method and test case”. J. Hydrology
(2009).
[PuRa] C. Puech, D. Raclot. “Using geographic information systems and aerial
photographs to determine water levels during floods”. Hydrol. Process., 16, 1593 – 1602,
(2002).
[RoDa] H. Roux, D. Dartus. “Use of Parameter Optimization to Estimate a Flood
Wave: Potential Applications to Remote Sensing of Rivers”. J. Hydrology (2006). |
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