Polyphemus is a modeling system for air quality. As such, it is designed to yield up-to-date simulations in a reliable framework: aerosols, data assimilation, ensemble forecast and daily forecasts. Its completeness allows to deal with many fields: photochemistry, heavy metals, radionuclides, etc . It is able to handle simulation from local to continental scale, with several physical models.
It is divided into three main parts:
libraries that gather data processing tools (SeldonData), physical parameterizations (AtmoData) and postprocessing abilities (AtmoPy);
programs for physical preprocessing and chemistry-transport models (Polair3D, Castor and Gaussian models);
drivers on top of the models in order to implement advanced simulation methods such data assimilation algorithms.
Clime is involved in the overall design of the system and in the development of advanced methods in data assimilation and ensemble forecast (through drivers and post-processing). The main achievements in 2006 are:
a strong improvement in the models interface,
the implementation of optimal interpolation, ensemble Kalman filter, reduced-rank Kalman filter and 4D-Var,
the release of Polyphemus 1.0 (http://www.enpc.fr/cerea/polyphemus/ ).