GPS network in South of France for better understanding and prediction of heavy rains
Water vapor distribution plays a significant role in the understanding of atmospheric mechanisms and weather prediction. But presently there is a lack of knowledge about the humidity field due to a shortage of current meteorological observations. Over the last decade, GPS is not only used as a global positioning system but can also deliver induced water vapor delay and then estimate the integrated water vapor.
South of France and particularly the Mediterranean littoral are characterized by frequent catastrophic rains. As part of the CYPRIM project (CYclogenesis and Intensive Precipitation over Mediterranean Region) and OHM-CV (Mediterranean Hydro-Meteorological Observatory - Cévennes Vivarais) GPS measurements were carried out to study these strong events. To increase number of measurement sites and to perform a real-time data recording, we are currently setting ten new GPS sites. These stations will be used in parallel with existing stations from diverse projects to get a tightened network (N42° to N45° and E2° to E6°).
In a first approach the network will provide data for the Zenital Tropospheric Delay, the Integrated Water Vapor and the Slant Integrated Water Vapor. Also, the LOFFT_K software developed by Geosciences Montpellier laboratory for tropospheric tomography will be used to compute 3D water vapor field. On the one hand, a systematic study of GPS data will be characterized and compared with other meteorological data. On the other hand, Aladin Meteo France model will be used to evaluate the data assimilation impact. This study will contribute to a better understanding and improvement of prediction during strong meteorological events over Mediterranean region.
HyMeX – Hydrological cycle in the Mediterranean Experiment 2010-2020