Presentation of Pierre Brousseau during the 2nd AROME training course, Lisbon, 4-7 March 2008 : "A mesoscale data assimilation system for operations : the AROME RUC", PierreBrousseau, Y. Seity, L. Auger, L.Berre, T.Montmerle, E. Wattrelot, C. Faccani
Outlines
- General ideas on data assimilation
- The AROME data assimilation system
- Background-error Statistics
- Assimilation experiments
Conclusion
- A prototype for the AROME data assimilation system is currently being tested at Météo-France.
(* It is supplied by the same kind of observation as the ALADIN-FRANCE operational suite. - The background-error statistics for AROME have been calculated by an ensemble methode using the same multivariate formulation as in ALADIN-France. Compared to the ALADIN-FRANCE ones, background-error standard deviations are increased and horizontal correlation length scales are much shorter: Analysis increments are strongerand narrower.
- This prototype shows its ability to improve analysis and forecasts, giving a more realistic depiction of initial conditions.
- The general benefit of the analysis appears during the first 12-hour forecast ranges, then lateral conditions mostly takeover the model solution.
Outlook
- Works currently in progress on :
- the use of observations at a higher spatial resolution (airep, IR radiances,…).
- the assimilation of observations more representative of mesoscale like RADAR winds and reflectivities (see also the talk of Eric Wattrelot).
- A surface assimilation for AROME (see also the talk of Rafiq Hamdi).
- Works are planned in orderto takea better advantageof high-frequencyobservations using:
- 3D-FGAT (First Guess at Appropriate Time) assimilation scheme
- Incremental Digital Filter Initialization allowing 1-h cycling
- AROME schedule :
- April 2008 : AROME pre-operational suite managed by operational team (3-h RUC, RADAR winds,…).
- October 2008 : AROME declared operational at Meteo-France (?)
