Llasat, Maria-Carmen (Department of Astronomy and Meteorology, University of Barcelona, Spain)
Gibergans-Baguena, Jose (same affiliation)
Guilbaud, Sophie (LTHE, Grenoble, France)
Rodriguez, J.Y. (EDF-DTG, Grenoble, France)
It is obvious that the data obtained from the radiosounding ascents are essential for the forecasting, analysis or diagnosis of the weather. The objective of this paper is to show two other aspects in using the thermodynamic data: first, the classification of daily rain (mainly if heavy rains have took place) in basis to the local information provided by the most representative radiosounding; second, the improvement of the Analogous Methos developped by EDF and the LTHE in Grenoble (France), to the rainfall forecasting. The analysis is based in some partial results obtained previously in the study of heavy rainfall events in Catalonia (Spain). The radiosounding station selected for this study has been Nimes (France). The data have been provided by the LTHE from Grenoble, and are extended from 1953 until 1983, it is to say, 30 years with data at 00 UTC and 12 UTC. However, taking into account that some days are lost or some data are wrong, before to begin teh statistical and meteorological analysis, the serie has been submitted to a quality control. Once the bad data are changed, interpolated or eliminated, a statistical analysis of all the thermodinamical variables has been made.
All this information has been treated from an statistical point of view (without forget their physical meaning) for all the data serie. Afterwards, daily rainfall for five zones placed in the South of France, and for the same period have been took. Taking into account the accumulated daily rainfall a classification of the different days have been made. The same statistical analysis made for all the serie has been made for each "kind of rainy day". The results obtained permit to ellaborate a certain kind of test based in the thresholds of some of the previous variables, in order to deduce the kind of rainy event. Besides this, some meteorological conclussions are obtained.