次世代超音波流速計による感潮域の流量と水温?塩分の連続モニタリング

摘要

Water discharge in a shallow tidal estuary had been continuously measured using a next-generation acoustic velocitimeter (NAV), which takes advantage of innovative acoustic tomogra?phy technology. In addition to discharge, mean water temperature and salinity were deduced from processing the sound speed data collected by the NAV. Sound paths were examined by ray tracing. Results revealed that sometimes salt wedge under the transducer caused sound paths to be reflected, so those sound paths were not able to penetrate into bottom layers. Therefore, in some observations calculated discharge was corrected using a velocity profile of density currents. Obtained discharge was compared with that of acoustic Doppler current profilers (ADCPs). Dis?charge, water temperature and salinity obtained from NAV data fulfilled an acceptable compliance with results derived from ADCPs and temperature/salinity sensors.