Towards a 2DEnVar surface data assimilation approach within the convective scale numerical weather prediction model AROME-France
Résumé
Surface data assimilation (DA) plays a key role in the initialisation of soil variables in coupled surface-atmosphere numerical weather prediction (NWP) models. Météo-France, as many other NWP centres, uses an operational surface DA method based on an optimal interpolation (OI), implemented more than 30 years ago. The current surface DA system implemented at Météo-France in the operational limited-area AROME-France model operates in two steps. First, a two-dimensional OI method analyses the diagnostic screen-level parameters, which are then used to initialise the prognostic soil variables according to a onedimensional OI method. This article presents the implementation and the results of a new two-dimensional ensemble-based variational (2DEnVar) system, Marimbordes et al. in OI.