[HDS16-P08] Observation of Coupled Seiche System in Ise Bay and Mikawa Bay by HF Radar
Keywords:Seiche, Ise Bay, HF Radar
We used the data observed by each two oceanographic radars installed in Nabeta (NABE) and Tsumatsuzaka (MATU) in Ise Bay, and MITO and MAGUSA in Mikawa Bay. We also examined the data obtained by tide gauge records to compare the effect of tsunami with the radar observations. To analyze the total velocity of the currents generated by the seiche, we used an Empirical Orthogonal Function (EOF). To verify the physical property of the results of the EOF analysis, we calculated the natural oscillation modes by the numerical model proposed by Loomis. The results of EOF analysis showed that the oscillation modes of 120-140 and 60-80 minutes period bands were distributed widely, whereas the oscillation mode of 30-40 minutes period band was distributed locally in Ise Bay. The EOF spatial patterns of each period were good agreement with numerical models.
At the time of the arrival of the tsunami, the sea surface height of the inner part of Mikawa Bay and Ise Bay oscillated alternately. Because Mikawa bay is coupled with Ise Bay on the entrance of the bay, there are some oscillations such as two simple coupled pendulums connected by a spring. In addition to the oscillation modes of Ise Bay, we will show the pendulum system in detail.