206 citations · 429 across the 12 of their papers we have counts for
13 papers
Parameter sensitivity analysis of a sea ice melt pond parametrisation and its emulation using neural networks
Simon Driscoll, Alberto Carrassi, Julien Brajard +3
Accurate simulation of sea ice is critical for predictions of future Arctic sea ice loss, looming climate change impacts, and more. A key feature in Arctic sea ice is the formation…
Super-resolution data assimilation
Sébastien Barthélémy, Julien Brajard, Laurent Bertino +1
Increasing the resolution of a model can improve the performance of a data assimilation system: first because model field are in better agreement with high resolution observations,…
Probabilistic forecasts of sea ice trajectories in the Arctic: impact of uncertainties in surface wind and ice cohesion
Sukun Cheng, Ali Aydoğdu, Pierre Rampal +2
We study the response of the Lagrangian sea ice model neXtSIM to the uncertainty in the sea surface wind and sea ice cohesion. The ice mechanics in neXtSIM is based on a brittle-li…
Combining data assimilation and machine learning to infer unresolved scale parametrisation
Julien Brajard, Alberto Carrassi, Marc Bocquet +1
In recent years, machine learning (ML) has been proposed to devise data-driven parametrisations of unresolved processes in dynamical numerical models. In most cases, the ML trainin…
Bayesian inference of chaotic dynamics by merging data assimilation, machine learning and expectation-maximization
Marc Bocquet, Julien Brajard, Alberto Carrassi +1
The reconstruction from observations of high-dimensional chaotic dynamics such as geophysical flows is hampered by (i) the partial and noisy observations that can realistically be…
Combining data assimilation and machine learning to emulate a dynamical model from sparse and noisy observations: a case study with the Lorenz 96 model
Julien Brajard, Alberto Carassi, Marc Bocquet +1
A novel method, based on the combination of data assimilation and machine learning is introduced. The new hybrid approach is designed for a two-fold scope: (i) emulating hidden, po…
Assimilation of semi-qualitative sea ice thickness data with the EnKF-SQ
Abhishek Shah, Laurent Bertino, Francois Counillon +2
A newly introduced stochastic data assimilation method, the Ensemble Kalman Filter Semi-Qualitative (EnKF-SQ) is applied to a realistic coupled ice-ocean model of the Arctic, the T…
Assimilation of semi-qualitative observations with a stochastic Ensemble Kalman Filter
Abhishek Shah, Mohamad El Gharamti, Laurent Bertino
The Ensemble Kalman filter assumes the observations to be Gaussian random variables with a pre-specified mean and variance. In practice, observations may also have detection limits…
Data Assimilation in the Geosciences - An overview on methods, issues and perspectives
Alberto Carrassi, Marc Bocquet, Laurent Bertino +1
We commonly refer to state-estimation theory in geosciences as data assimilation. This term encompasses the entire sequence of operations that, starting from the observations of a…
Extending the square root method to account for additive forecast noise in ensemble methods
Patrick N. Raanes, Alberto Carrassi, Laurent Bertino
A square root approach is considered for the problem of accounting for model noise in the forecast step of the ensemble Kalman filter (EnKF) and related algorithms. The primary aim…
Local ensemble transform Kalman filter, a fast non-stationary control law for adaptive optics on ELTs: theoretical aspects and first simulation results
Morgan Gray, Cyril Petit, Sergey Rodionov +4
We propose a new algorithm for an adaptive optics system control law, based on the Linear Quadratic Gaussian approach and a Kalman Filter adaptation with localizations. It allows t…
Local Ensemble Transform Kalman Filter: a non-stationary control law for complex adaptive optics systems on ELTs
Morgan Gray, Cyril Petit, Sergey Rodionov +3
We propose a new algorithm for an adaptive optics system control law which allows to reduce the computational burden in the case of an Extremely Large Telescope (ELT) and to deal w…
Towards the inclusion of wave-ice interactions in large-scale models for the Marginal Ice Zone
Timothy Williams, Luke Bennetts, Dany Dumont +2
A wave-ice interaction model for the marginal ice zone (MIZ) is reported, which involves both the attenuation of ocean surface waves by sea ice and the concomitant breaking of the…