Geoscience Reference
In-Depth Information
8
Retrieving High Resolution 3-D Wind Vector
Fields from Operational Radar Networks
Olivier Bousquet
Météo-France, Centre National de Recherches Météorologiques
France
1. Introduction
The ability to retrieve 3-D wind vector fields in a fully operational framework has a
potentially wide-ranging impact on a variety of meteorological research and operational
meteorological applications. This capability was recently evaluated by the French Weather
Service in the course of an upgrade program aiming to introduce Doppler and dual-
polarimetric technologies within its radar network. Starting in November 2006, real-time
multiple-Doppler wind fields have been produced routinely every 15 minutes for 2 years
within a 320x320 km² domain centered on Paris city (Bousquet et al. 2007, 2008a). The
evaluation of wind fields synthesized in this framework was carried out from observations
collected in a variety of weather situations including low-level cyclones, frontal systems and
squall lines. Wind vectors retrieved in the greater Paris area were generally proved very
realistic and have been found reliable enough to be used for research applications
(mesoscale meteorology, statistical analysis) and numerical model verification (Bousquet et
al. 2008b). In order to prepare for the field phase of the international Hydrological
Mediterranean Experiment (HyMeX
1
), which will be conducted in 2012-2013, this analysis
has later been successfully extended to regions of complex terrain located in the southern
part of the country (Bousquet, 2009). The ability to perform operational wind retrieval in
mountainous areas is an important step to improve our understanding of orographic
precipitation developing in these usually poorly instrumented regions, and also
demonstrates that operational real-time wind retrieval could potentially be carried out over
the entire French territory - ground elevation exceeds 500 m over ~ 1 fifth of mainland
France - which was the initial objective of the French Weather Service when this experiment
was started.
In 2009, the wind retrieval analysis was therefore extended to the full
metropolitan radar network with the goal to implement an operational, nationwide, three-
dimensional reflectivity and wind field mosaic to be ultimately delivered to forecasters and
modelers, as well as automatic nowcasting systems for air traffic management purposes. In
this composite analysis, which is expected to become operational in 2013, data collected by
all 24 radars of the French radar network are concentrated, pre-processed and combined in
real-time at a frequency of 15 minutes to retrieve the complete wind vector (u,v,w) and
1
HyMeX is an international program that aims at a better understanding and quantification of the
hydrological cycle and related processes in the Mediterranean, with emphasis on high-impact
orographic weather events. Information about this program can be found on http://www.hymex.org
