Satellite microwave links revealed!
1 Filippo Giannetti
1 Department of Information Engineering, University of Pisa, Italy
Opportunistic rain rate estimation based on satellite microwave links (SMLs) emerged as a very appealing solution which can effectively and reliably integrate rain measurements by conventional instrumentation and commercial microwave links (CMLs), thanks to the wide-area coverage of the satellite, the availability of easy-to-install low-cost receiving equipment and the possibility of developing simple ad-hoc devices for the measurement of the received satellite signal strength. The talk will first present a description of the SML processing chain, including some considerations on tropospheric models. Then, the sensitivity of the algorithm to the parameter settings and its performance in terms of rain estimate accuracy will be numerically assessed. After, 2D interpolation techniques for sparse SML sensors will be presented for both a synthetic and a real scenario. Some issues related to 3D rain retrieval, considering the possible vertical variability of rain intensity, will be addressed, too. Concluding, challenges and perspectives of SML-based rainfall measurements will be discussed.
Satellite microwave links: operational use and focus on mitigating some sources of errors
1 François Mercier-Tigrine, 1 Maxime Turko, 1 Louise Gelbart, 2 Laurent Barthès, 2 Aymeric Chazottes, 2 Cécile Mallet
1 HD Rain, Paris, France
2 LATMOS-IPSL, Paris-Saclay University / Versailles St Quentin University, Guyancourt, France
Satellite microwave links (SML) are deployed and operated in the form of low-cost sensors by the company HD Rain for two years in the south of France (700 sensors) and in other countries, including Ivory Coast (150 sensors) and Georgia (30 sensors). In this presentation, we first introduce the technology used (sensor and its measurement, energy supply, data sampling and transmission) as well as comparisons with radar and rain gauge data. Then, we focus on sources of uncertainty or errors that are specific to SMLs or that have been relatively little studied to date in the context of SMLs and present results or perspectives to cope with them. This will include considering the melting layer, the wet antenna effect, and limits due to the importance of background noise in case of heavy rain (when raindrop radiation is no longer negligible in the face of a strongly attenuated satellite signal) or even in cases of saturation (when the signal is totally attenuated).
