| It is known the coastal sea level is affected by the variation of the offshore. Along the Japanese southern coast facing to the Kuroshio, it is expected variations of sea level are strongly controlled by the Kuroshio fluctuations. On the other hand, the Kuroshio is also known to change its position at the south of Japan main land; namely, the Kuroshio has two typical path, stationary large meander path and non-large meander one. So the effects on sea level along the southern coast of Japan might be different whether the Kuroshio takes stationary large meander path or not. However, the effects have not been quantitatively studied since the observations of the offshore field are difficult. Recently, the satellite altimetry has provided good description of offshore variations. Altimeters on TOPEX/POSEIDON and ERS-1/2 supply long-term high-resolution data, although the Kuroshio did not take stationary large meander path during the observation period. On the contrary, GEOSAT covers a stationary large meander period from December 1986 to August 1988, although the resolution of the data is not very high. In this study, we use these satellite altimetry data to estimate the effect of the Kuroshio on the sea level along southern coast of Japan. We determine cross correlation coefficients between sea level data and sea surface dynamic topography (SSDT) by using local tide gauge records and satellite altimetry data. And the patterns of the coastal sea level variation at the eastern and the western sides of the Kii Peninsula is found different in non-large meander periods, while in the stationary large meander period, they becomes same. This would be interpreted that strong Kuroshio flow close to the Kii Peninsula in non-large meander period causes some kind of eddy separation at the Kii Peninsula. In the non-large meander periods, opposite correlation southern coastal sea levels and the offshore edge of the Kuroshio axis is also found at the southern coast of Kyushu. The coastal sea level is suggested to decrease when the Kuroshio is stronger. This relation is consistent when coastal cooling by intrusion of cold bottom water is induced by increased bottom Ekman transport. |
|
|