High rate GNSS measurements for detecting non-hydrostatic surface wave. Application to tidal borein the Garonne River

Abstract

This study presents the results of the use of high frequency Global Navigation Satellites Systems (GNSS) data for the detection and the characterization of tidal bores. The experiment took place the 31st of August 2015 in the Garonne River, at 126 km upstream the mouth of the Gironde estuary. The GNSS data acquired on a buoy at a sampling rate of 20 Hz were processed with a differential GNSS technique using the RTKLIB freeware. GNSS-based elevation of the free surface provides accurate estimates of the tidal bore first wave amplitude (1.34 m) and period (3.0 s). These values were in good agreement with values obtained using ADCP measurements.