A5007632328- Meteorological Phenomena and Simulations
- Hydrology and Watershed Management Studies
- Flood Risk Assessment and Management
- Climate variability and models
- Reservoir Engineering and Simulation Methods
- Fluid Dynamics and Turbulent Flows
- Mathematical Biology Tumor Growth
- Computational Fluid Dynamics and Aerodynamics
- Hydrology and Sediment Transport Processes
- Hydrology and Drought Analysis
- Groundwater flow and contamination studies
- Advanced Numerical Methods in Computational Mathematics
- Probabilistic and Robust Engineering Design
- Hydrological Forecasting Using AI
- Geophysics and Gravity Measurements
- Navier-Stokes equation solutions
- Model Reduction and Neural Networks
- Advanced Control Systems Optimization
- Cruise Tourism Development and Management
- Soil erosion and sediment transport
- Plant Water Relations and Carbon Dynamics
- Seismic Imaging and Inversion Techniques
- Soil and Unsaturated Flow
- Stability and Controllability of Differential Equations
- Arctic and Antarctic ice dynamics
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2016-2025
Gestion de l'Eau, Acteurs, Usages
2014-2024
Centre de Coopération Internationale en Recherche Agronomique pour le Développement
2024
AgroParisTech
2024
Université de Montpellier
2022-2024
Bureau de Recherches Géologiques et Minières
2024
Institut Agro Montpellier
2024
Institut de Recherche pour le Développement
2024
Institute of Numerical Mathematics
2023
Russian Academy of Sciences
2023
Abstract Space‐borne instruments can measure river water surface elevation, slope, and width. Remote sensing of discharge in ungauged basins is far more challenging, however. This work investigates the estimation from simulated observations forthcoming Surface Water Ocean Topography (SWOT) satellite mission using a variant classical variational data assimilation method “4D‐Var.” The scheme simultaneously estimates discharge, bathymetry, bed roughness context 1.5 D full Saint‐Venant hydraulic...
The problem of variational data assimilation for a nonlinear evolution model is formulated as an optimal control to find the initial condition function (analysis). equation analysis error derived through errors input (background and observation errors). This used show that in case covariance operator can be approximated by inverse Hessian auxiliary which involves tangent linear constraints. constructed quasi-Newton BFGS algorithm when solving problem. A fully ensemble procedure developed...
Knowledge of river bathymetry is crucial for accurately simulating flows and floodplain inundation. However, field data are scarce, the depth shape channels cannot be systematically observed via remote sensing. Therefore, an efficient methodology necessary to define effective bathymetry. This research reconstructs from existing global digital elevation models (DEMs) water surface observations with minimum human intervention. The can considered a 1D geometric inverse problem, it potentially...
Knowledge of river bathymetry is crucial for accurately simulating flows and floodplain inundation. However, field data are scarce, the depth shape channels cannot be systematically observed via remote sensing. Therefore, an efficient methodology necessary to define effective bathymetry. This research reconstructs from existing global digital elevation models (DEMs) water surface observations with minimum human intervention. The can considered a 1D geometric inverse problem, it potentially...
Abstract. This contribution presents a regionalization approach to estimate spatially distributed hydrologic parameters based on: (i) the SMASH (Spatially Modelling and ASsimilation for Hydrology) hydrological modeling assimilation platform (Jay-Allemand, 2020; Jay-Allemand et al., 2020) underlying French national flash flood forecasting system Vigicrues Flash (Javelle 2019); (ii) variational algorithm from (Jay-Allemand 2020), adapted high dimensional inverse problems; (iii) spatial...
Abstract The problem of variational data assimilation for a nonlinear evolution model is formulated as an optimal control to find the initial condition function (analysis). contain errors (observation and background errors); hence there error in analysis. For mildly dynamics analysis covariance can be approximated by inverse Hessian cost functional auxiliary problem, stronger nonlinearity ‘effective’ Hessian. However, it has been noticed that not posterior from Bayesian perspective. While...
Summary Estimating river discharge from in situ and/or remote sensing data is a key issue for evaluation of water balance at local and global scales management. Variational assimilation (DA) powerful approach used operational weather ocean forecasting, which can also be this context. A distinctive feature the estimation problem likely presence significant uncertainty principal parameters hydraulic model, such as bathymetry friction, have to included into control vector alongside discharge....
Abstract. Calibration of a conceptual distributed model is challenging due to number reasons, which include fundamental (model adequacy and identifiability) algorithmic (e.g., local search vs. global search) issues. The aim the presented study investigate potential variational approach for calibrating simple continuous hydrological (GRD; Génie Rural involved in several flash flood modeling applications. This defined on rectangular 1 km2 resolution grid, with three parameters being associated...
The SWOT satellite has the potential to transform global hydrologic science by offering simultaneous and synoptic estimates of river discharge other hydraulic variables. Here, we present first from during initial orbital configuration mission. A preliminary accuracy assessment April 2023 shows results consistent with pre-launch expectations: can track dynamics without any gauge information. It captures magnitude correctly in some cases but bias others. Correlations a set representative...
Abstract. The problem of variational data assimilation (DA) for a nonlinear evolution model is formulated as an optimal control to find the initial condition, boundary conditions and/or parameters. input contain observation and background errors, hence there error in solution. For mildly dynamics, covariance matrix solution can be approximated by inverse Hessian cost function. problems with strongly new statistical method based on computation sample Hessians suggested. This relies efficient...
The optimal sensor-location problem is considered in the framework of variational data assimilation for a large-scale dynamical model governed by partial differential equations. This formulated as an optimization design function defined on limited-memory approximation inverse Hessian cost function. expression gradient with respect to coordinates derived via adjoint derivative. An efficient algorithm evaluation suitable applications suggested. exploits special structure small number Ritz...
Abstract This paper develops the adjoint sensitivities to free surface incompressible barotropic Euler equations in order allow for assimilation of measurements currents and elevations into an unsteady flow solution by boundary control. To calculate a variation variable, mapping is used vertical shift problem fixed domain. Then evaluated from Jacobian matrix mapping. After calculating variable applying inverse transformation, tangent linear model considered original space where are then...
Abstract The problem of variational data assimilation (estimation) for a nonlinear model is considered in general operator formulation. Hessian-based methods are presented to compute the estimation error covariances. importance dynamic formulation and role Hessian its inverse discussed.
Abstract. Flash flood alerts in metropolitan France are provided by SCHAPI (Service Central Hydrométéorologique et d’Appui à la Prévision des Inondations) through the Vigicrues service, which is designed to work ungauged catchments. The AIGA method implemented for forecasting on small- and medium-scale watersheds. It based a distributed hydrological model accounting spatial variability of rainfall catchment properties, radar observation inputs. Calibration parameters describing these...