Upcoming 2012 JCSDA Seminars

One of the many scientific challenges in the field of numerical weather prediction is to extract useful information on the atmospheric boundary layer using observations from remote sensing microwave instruments such as AMSU-A, AMSU-B/MHS or SSMIS. These data contribute increasingly to improve short to medium range forecasts, but also to improve re-analyses. Better use of these data often requires appropriate representation of the surface in the models, in both emissivity and temperature. This is achieved over sea, and satellite data have a tremendous impact on the atmospheric analyses over oceans. Over land, the surface emissivity is highly variable and may cause biases in the forward model if its temporal and spatial variability are not well taken into account. In such a situation, the model cannot produce realistic simulations of observations sensitive to the surface and may reject useful observations, including those not sensitive to the surface. This case concerns in particular the land and sea ice surfaces for which the surface emissivity is particularly challenging to model. During the seminar, some of the work carried out at Météo-France for a better description of the emissivity of land and sea ice surfaces will be summarized. The methodology used for estimating the emissivity in the model and its impact on the performance of the radiative transfer model will be presented. The impact of a proper modeling of the land and sea ice emissivity, in terms of forecast skill and quality of analyses, will be discussed.