Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Forecasting rain - Radars for estimating rainfall rates

06.11.2008
To be effective, flood warning systems use rainfall data available in real time. These data come from the ground observation network and estimations made based on the national network of climate radars operated by Météo France.

Today, mountain zones are only partially covered by this rain detection technology. Within the INTERREG project, a new generation of radars is being tested by Cemagref in the Var department, a mountainous region with a high flood risk. The radar is currently located in the countryside immediately inland from Nice.

Measuring the intensity of rain as it is falling is indispensable to anticipating rapidly rising waters and reacting to the associated flood risk. To the classical rain gauges installed throughout the area, new radar technologies were added in the 1990s to detect rain and measure the accumulation of precipitations in real time.

Today, Météo France has a national network of 24 weather radars available within approximately 100 km. However, all regions in France are not covered by this mesh, in particular the mountain zones where the relief masks downstream rain zones by creating an obstacle to wave displacement. Within the FRAMEA1 project, a new radar technology developed by Novimet ² is being tested at the Aix-en-Provence Cemagref. The experiments conducted in the Maures massive have proven to be highly promising.

[1 Flood forecasting using Radar in Alpine and Mediterranean Areas (FRAMEA)]
[2 A young company split off from the CNRS]
- More compact and less expensive radars
The radars used at the beginning to monitor planes flying overhead were extended to the detection and quantification of precipitations. Large-scale radars, 6–8 m in antenna diameter, are used today in weather stations located in the plains. In mountain zones, the number of radars must be multiplied in relation to the relief, which requires smaller and less expensive models. The new Hydrix radar responds to these demands. However, by reducing the diameter of the parabolic antenna to 1.5 m, the wave frequency must be boosted, which increases the attenuation of waves during their displacement.

To compensate this signal attenuation effect, a profiling algorithm (ZPHI) is used. Finally, the radar operates in double polarization, which provides information on the size of the rain drops and estimates precipitations without resetting ground network observations. Today, in a doctoral dissertation supervised by both Cemagref and the firm Novimet, this new radar technology is being tested in the Var department, a mountainous region that experiences very intense flash floods.

- Results that are coherent with ground readings

The Hydrix is installed near Réal Collobrier, Cemagre’s instrumented research catchment, located in the Maures massif. The total rainfall in autumn 2006 calculated by the radar was compared to the rain gauge readings on the ground and to the accumulation estimated by one of the nearby radars belonging to the Météo France network. Within a 60- to 80-km radius, the data supplied by the radar were in coherence with the quantities of rain collected on the ground. In addition, the algorithmic signal processing retransmitted rain gauge data in real time that were as good quality as the data sent by the classical radar managed by Météo France.

Today, the research is continuing so as to integrate the rain gauge data supplied by the radar into existing rainfall-runoff models. By converting rainfall into runoff, these mathematical tools can calculate the runoff of rivers at the outlet of a catchment. These rainfall and runoff data then feed the flood warning systems, such as the Aiga system developed by Cemagref and Météo France in 2005. By completing the existing radar network, the Hydrix technology will contribute to the extension of the flood warning system over the entire area, including mountainous zones.

Marie Signoret | alfa
Further information:
http://www.cemagref.fr
http://www.cemagref.fr/Informations/Presse/InfMediaEV/infomedia85EV/im85_pluie_article1.htm

More articles from Ecology, The Environment and Conservation:

nachricht International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>