[A-OS16] Coastal ocean circulation and material cycle

[AOS16-P10] Estimation of velocity around river fronts using drifting buoys

*Yusei Umeda¹, Shinichiro Kida², Tomonori Isada³, Kiyoshi Tanaka⁴ (1.Interdisciplinary Graduate School of Engineering Sciences,Kyushu University, , 2.Research Institute for Applied Mechanics,Kyushu University, 3.Field Science Center for Northern Biosphere,Hokkaido University, 4.University of Tokyo)

Keywords:river fronts, drifting buoys, GNSS, UAVs

To understand the mechanism behind the mixing of oceanic water and river water along river fronts, observations were made using UAVs and drifting buoys in Akkeshi Bay, Hokkaido.A river front is a salinity boundary between oceanic water and river water that often forms along the coast, and bubbles often converge along the front.High-frequency, high-resolution aerial images were taken using UAVs to estimate the flow field along the river front, which often changes on a scale of several seconds and meters.Past studies have successfully estimated the flow field along the front by tracking the movement of bubbles using the aerial image, but the method fails where there are no bubbles to track. The goal of this study is to capture the flow field surrounding river fronts using buoys where bubbles do not exist.
By mounting GNSS on buoys, we were able to estimate the flow field that changed on the order of a few seconds using high resolution latitude and longitude information.
Our next plan is to evaluate the flow field with that estimated along the front in more detail using aerial images, in addition to that measured using ADCP mounted drone boats.