Use of Cell Phone Networks for Rainfall Estimation in the City of Luxembourg - RAINCELL

Coordinating Institution: CRP Gabriel Lippmann
Contracting Partner(s): PT Luxembourg (TELECOM) , Institut Royal Météorologique (B)
From: 01/04/2009
To: 31/03/2011
Budget: 378,000.00€
Contact(s): Pfister Laurent

Summary

Accurate precipitation estimation is crucial for the investigation and prediction of the hydrological behavior of catchments. Currently, the measurement of precipitation is predominantly based on raingauges. However, this approach is subject to large uncertainties, considering the large spatial variability of rainfall. In fact, raingauges have surface areas that are very small (a few squared centimeters) in comparison with common catchment sizes (of the order of several squared kilometers).

Recently, alternative rainfall estimation methods have been explored, which are based on microwave devices. These approaches have the advantage of covering larger areas, providing data at the necessary scale. These approaches include weather radars and microwave links. Weather radars have been operational since the 1980's, and can provide high temporal resolution, large-scale rainfall fields.

While useful for interpreting rainfall patterns and for rainfall forecasts, these instruments cannot be considered as substitutes for raingauges, particularly for hydrologic applications. In fact, the accuracy of weather radar in rainfall amounts is considerably lower than that of raingauge measurements. Microwave links differ from weather radars in the sense that instead of measuring reflected radiation they measure transmitted radiation between an emitter and a receiver.

While not being able to provide rainfall fields, these set-ups can thus accurately determine rainfall totals along a link. The RAINCELL project investigates the potential of microwave links for providing accurate high- resolution (temporal and spatial) rainfall measurements in the city of Luxembourg. High-resolution precipitation estimates are in fact of crucial importance for urban hydrology. Urban areas are generally impervious and therefore constitute extremely fast responding systems. The prediction of their behavior, which is necessary for sewer system management, river regulation and risk assessment, is strongly conditioned by the uncertainty of precipitation data. In 2009, a complete instrumental set-up, comprising two microwave links and 10 recording raingauges has been installed in the city of Luxembourg.

The city of Luxembourg has provided substantial technical support for the real-time transmission of rainfall data to the CRP-Gabriel Lippmann. The installation and maintenance of the microwave links is supervised by the Entreprise des Postes et Télécommunications. The set-up allows a comprehensive testing of microwave links in comparison with traditional ground-based precipitation measurements, as well as weather radar data from Wideumont (B), provided by the Royal Meteorological Institute of Belgium.

Figure 1: Project team (photo taken at the Meteorologic Station of Wideumont (Belgium)

Figure 2: Micro-wave test link currently installed on the site of P&T, Luxembourg-Kockelscheuer