SNR-Based Water Height Retrieval in Rivers: Application to High Amplitude Asymmetric Tides in the Garonne River
| Autor: | Guillaume Detandt, Natalie Bonneton, Philippe Bonneton, José Darrozes, Pierre Zeiger, Nicolas Roussel, Frédéric Frappart |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
reflectometry
water height 010504 meteorology & atmospheric sciences GNSS-R Science 0211 other engineering and technologies Elevation asymmetric tides Geodetic datum 02 engineering and technology Filter (signal processing) 01 natural sciences GNSS applications Flash flood General Earth and Planetary Sciences dynamic SNR Antenna (radio) Reflectometry Geology Noise (radio) 021101 geological & geomatics engineering 0105 earth and related environmental sciences Remote sensing |
| Zdroj: | Remote Sensing, Vol 13, Iss 1856, p 1856 (2021) Remote Sensing; Volume 13; Issue 9; Pages: 1856 |
| ISSN: | 2072-4292 |
| Popis: | Signal-to-noise ratio (SNR) time series acquired by a geodetic antenna were analyzed to retrieve water heights during asymmetric tides on a narrow river using the Interference Pattern Technique (IPT) from Global Navigation Satellite System Reflectometry (GNSS-R). The dynamic SNR method was selected because the elevation rate of the reflecting surface during rising tides is high in the Garonne River with macro tidal conditions. A new process was developed to filter out the noise introduced by the environmental conditions on the reflected signal due to the narrowness of the river compared to the size of the Fresnel areas, the presence of vegetation on the river banks, and the presence of boats causing multiple reflections. This process involved the removal of multipeaks in the Lomb-Scargle Periodogram (LSP) output and an iterative least square estimation (LSE) of the output heights. Evaluation of the results was performed against pressure-derived water heights. The best results were obtained using all GNSS bands (L1, L2, and L5) simultaneously: R = 0.99, ubRMSD = 0.31 m. We showed that the quality of the retrieved heights was consistent, whatever the vertical velocity of the reflecting surface, and was highly dependent on the number of satellites visible. The sampling period of our solution was 1 min with a 5-min moving window, and no tide models or fit were used in the inversion process. This highlights the potential of the dynamic SNR method to detect and monitor extreme events with GNSS-R, including those affecting inland waters such as flash floods. |
| Databáze: | OpenAIRE |
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