FIELD OBSERVATIONS IN SOME AREAS IN OKINAWA

Abstract

 Field observations of wave, flow, water temperature and salinity were conducted in some areas in Okinawa, Naha port, Urasoe and Shiraho coasts. Observational durations are 30 days in winter and summer. This report shows the following three topics. (1) Semidiurnal fluctuation of water temperature are apparent offshore areas of Naha port and Urasoe coast in summer. (2) Variations of flow patterns in winter and summer are revealed in Shiraho coast, typical fringing reefs. The reef currents are driven by gradient of elevation caused by wave setup. The difference of wave direction between winter and summer varies the reef currents. (3) Variations of water temperature are shown in Shiraho coast. Semidiurnal variation of water temperature is dominant under the calm condition. In the disturbed durations, vertical mixing is enhanced and the vertical distribution of water temperature is homogeneous.