Mesoscale data assimilation

Special efforts are being invested into developing strong data assimilation systems for ALADIN and AROME, using 3 key ingredients:

• a strong reliance on the IFS/ARPEGE data assimilation software, which provides particularly quick access to state-of-the-art global satellite data processing and science;
• an effort on using dense, regional data over Western Europe in order to add extra fine-scale information: geostationary Meteosat data, automatic mesoscale station data, and modern radar data, while keeping the IFS/ARPEGE philosophy of using as much as possible the original data with physical observation operators;
• original algorithmic developments using some new ideas from the theoricians of data assimilation (the long-standing support of Pr Olivier Talagrand from the LMD lab of CNRS and IPSL is gratefully acknowledged).

References

• Fischer C., T. Montmerle, L. Berre, L. Auger and S.E. Stefanescu, 2006: An overview of the variational assimilation in the ALADIN/FRANCE NWP system. Quart. Jour. Roy. Meteor. Soc.,613, pp. 3477-3492.
• Montmerle, T., F. Rabier and C. Fischer, 2006: Respective impact of polar orbiting and geostationary satellite observations in the Aladin/France NWP system. Accepted in Quart. Jour. Roy. Meteor. Soc.
• Brousseau, P. and Y. Seity, 2006: a first prototype for the AROME data assimilation system. Article in the ALADIN Newsletter no.30 of Nov 2006, pp.88-89.
• Stein, J., 2006: validation of the 3DVar assimilation scheme. Article in the ALADIN Newsletter no.29 of March 2006, pp.12-20.
• Guidard V., C. Fischer, M. Nuret and A. Dziedzic, 2006: Evaluation of the ALADIN 3D-Var with observations of the MAP campaign. Meteorology and Atmospheric Physics, 92, pp.161-173.
• Montmerle, T., J.-P. Lafore, L. Berre and C. Fischer, 2006: Limited area model error statistics over Western Africa : comparisons with mid-latitude results. Quart. Jour. Roy. Meteor. Soc., 132, pp.213-231.
• Sadiki W. and C. Fischer, 2005: A posteriori validation applied to the 3D-Var ARPEGE and ALADIN data assimilations system. Tellus 57A, pp.21-34.
• Berre, L., 2000: Estimation of synoptic and mesoscale forecast error covariances in a limited area model. Mon. Wea. Rev., 128, pp.644-667.