A new technique for measuring tidal currents by using a two‐site HF Doppler radar system

Abstract

We have measured surface currents by using a newly developed high‐frequency (HF) Doppler radar technique. The system was operated in lower Cook Inlet, Alaska, in July 1977. During one particular day, July 13, we analyzed the radar data collected every 30 min for 24 hours. By least squares fitting these data to two of the dominant tidal periods, 12.31 and 24.6 hours, we determined the spatial distribution of the tidal currents for each of these two periods. In addition, we determined the spatial distribution of the mean surface currents for this 24‐hour period. Our analysis of this data shows that near Kachemak Bay there is a distinct difference of the east‐west component of tidal flow in comparison with regions further from Kachemak. In addition, we observed longer period components for which we cannot determine the period. These components exhibited gyrelike spatial patterns. Our results demonstrate the use of HF radar techniques for resolving spatial and temporal currents which affect the nearshore environment.