This work is dedicated to the study of a model sensitivity to high frequency atmospheric forcing (10 meters wind and atmospheric pressure from ECMWF, ARPEGE and ALADIN meteorological models), in the European region of North East Atlantic, and more particularly in regional shelf areas such as Bay of Biscay. The model we are using (MOG2D) is barotropic, free-surface, finite element, covers the Bay of Biscay and is nested in a North East Atlantic domain.

In particular, the purpose of this study is to explore the model errors sub-space in presence of atmospheric forcing errors. This is done by an ensemble modelling approach (Monte-Carlo) in which the atmospheric fields are perturbed in a multivariate way : by generating an 'a priori' ensemble of perturbed atmospheric forcing fields, and computing the corresponding 'a posteriori' ensemble of model simulations, one can approximate the forecast errors of the model by ensemble spread statistics, such as background error Ensemble EOFs.

These statistics, in form of 3D-EOFs (Sea Level Anomaly, barotropic velocities), are used in a reduced-order sequential scheme (SEQUOIA, developped at LEGOS/POC) to constrain the model forecast. Preliminary results tend to show that 20 multivariate oceanic ensemble EOFs would be sufficient to represent the ensemble variance due to the atmospheric errors. The methodology is being tested for the month of November, 1999 in the form of Single Observation Experiments and Twin Experiments.
Our objective is then to move on to the assimilation of altimetric and tide gauges observations (corrected from Inverse Barometer effects) in the modelling domain in order to correct the model for the deficiencies of the atmospheric forcings fields.

Sensitivity to high-frequency atmospheric forcing of a model of the Bay of Biscay and North East Atlantic

More details in my Master/Engineer Degree report