Innovative Observing and Data Assimilation systems for severe weather events in the MEDiterranean. – IODA-MED

To better understand and better forecast HPEs IODA-MED proposed i) to collect additional and non-conventional observations in the marine upwind environment of the HPEs ii) to make better use of routinely available observations in the mesoscale data assimilation systems iii) to explore the potential of assimilating new observation types, especially observations related to the water cycle, and iv) to advance the quality of the mesoscale data assimilation systems. IODA-MED was a major contribution to the first intensive observing phase of HyMeX, HyMeX SOP1, organized in autumn 2012 and devoted to the study of intense precipitation and flash floods. IODA-MED took advantage of the strong national and international cooperation developed in the wider context of HyMeX

Some highlights of the project:
- the construction of the first data base which gathers all the atmospheric parameters relevant for the study of heavy precipitation in the Mediterranean area.
- the improvement of the assimilation system of the operational numerical weather prediction model of Météo-France thanks to a better use of routine observations and the use of additional non-standard observations
- the demonstration that this improvement leads to better precipitation forecasts
- a better understanding of the physical processes involved in heavy rain episodes and the identification of those which are still ill-represented in the models

The study of HPE is being pursued through new collaborative projects such as ANR MUSIC (Multiscale process studies of intense convective precipitation
events in Mediterranean, funded), ANR EXAEDRE (EXploiting new Atmospheric Electricity Data for Research and the Environment, in review) or NeWPHY (NExt generation models for Weather Prediction of High Impact events, EU Training network, submitted).

The project resulted in 28 peer-reviewed publications, most of them in partnership, and more than 100 communications at international conferences. This effort was accompanied by various valorisation activities: two articles in journals for the general public, contributions to press-conferences and many communications in the media (radio, TV, web).

During the autumn, western Mediterranean regions are prone to heavy precipitation and flash floods. Considerable efforts to improve the skill of the forecasts for such severe events have been made in recent years and significant progress has been obtained through the development of models permitting high-resolution convection. However, the accuracy of the forecasts is still insufficient to satisfy the demands of society in terms of amount, timing, and location of rainfall. Among the various factors limiting the predictability of heavy precipitation events (HPE), uncertainties in the model initial states play a major role. The central objective of IODA-MED is to improve HPE predictability by reducing the uncertainties on the initial state of the model. This will achieved by
i) collecting additional and non-conventional observations in the marine upwind environment of the HPEs,
ii) making better use of routinely available observations in the mesoscale data assimilation systems,
iii) exploring the potential of assimilating new observation types, especially observations related to the water cycle
iv) advancing the quality of the mesoscale data assimilation systems.

IODA-MED is part of the much wider HyMeX research initiative dedicated to the study of the hydrological cycle in the Mediterranean. IODA-MED is a major contribution to the first HyMeX special observing period scheduled for autumn 2012 and focussed on heavy precipitation and floods. IODA-MED will benefit from a strong national and international cooperative environment.