3rd HyMeX workshop 1-4 June 2009 Heraklion (Gournes), Crete-Greece
Upstream wind field conditions in the western Mediterranean basin monitored by a wind profiler radars networkFrédérique Said (Laboratoire d'Aérologie); Campistron B. and Lambert D.
A network of UHF-VHF wind profilers will be set up on the Mediterranean French coast, in order to describe first the inland and offshore dynamical conditions with the aim of studying the dynamics linked with the initiation of strong rainfall and flood events, and second the inland conditions of air-sea exchanges in case of Mistral or Tramontana winds as well as coastal dynamics (see Caccia, this issue). The purpose of this proposal is to extend this wind profilers network to a larger Mediterranean basin involving the French coast, Corsica (or Sardinia) and Balearic islands, able to provide mesoscale conditions above the Mediterranean sea over a long period extending over one or two years.
To evaluate the capabilities of the radar network, a preliminary work has been started with MESO-NH numerical model, using a simulation of a heavy rainfall event that occurred during October 2007: the individual vertical profiles of wind provided by the model for selected sites are used to simulate radar profiles. An optimal interpolation procedure based on these radar-like profiles was applied to different scenario of networks. The retrieved regional horizontal divergences/vorticity as well as the 3D winds are compared to the model output, on the equivalent areas. This comparison shows that i) the network is able to restore the model fields, ii) the network filters local perturbations (coastal effects for instance). The next step will be to use the networks results to optimize the profiler radars location on the coast.
The network will provide long term observations of upstream conditions over the basin that will be coupled, during the intensive observation periods, to aircraft measurements that will measure dynamics and thermo-dynamics over the area and provide the spatial variability inside the network. The network will also provide mean trajectories and dispersion plumes: the former will be compared to the constant volume balloon trajectories, in case the balloons over fly the network. We also expect to use vertical profiles of water vapour extracted from the radar profiler reflectivity (Kalapureddy et al., this issue).
The network implementation is planned to last a long period which will be a mean to fulfil some objectives of HYMEX as well as some CHARMEX objectives (gas and aerosol transport) programmes.