Study on Seasonal and Interannual Variations of Surface Circulation in the Sea of Okhotsk using Satellite Observations

利用TOPEX/Poseidon(T/P)高度计观测的10年海平面距平(SLA)资料，研究了鄂霍次克海包括东库页岛流(ESC)表层环流的季节和年际变化。T/P SLA清楚地记录了库页岛东海岸ESC的季节和年际变化，尽管海冰从1月到4月掩盖了该地区。由T/P SLA得到的表面流速异常与漂流浮标观测结果吻合较好。冬季海流强度较强，12月份的典型流速为30-40 cm/S，夏季基本消失。ESC的南向流动仅限于陆架和斜坡区域，并由两个速度核组成。ESC的这些特征与先前研究中报告的短期观察结果一致。对T/P SLA十年记录的分析证实，尽管ESC的强度年际变化很大，但ESC的结构在每年冬季都保持不变，季节循环每年都会重复。利用欧洲中期天气预报中心(ECMWF)再分析资料和散射计得到的风产品，讨论了ESC的季节和年际变化与鄂霍次克海风生环流的关系。利用T/P SLA还揭示了千岛盆地反气旋性涡旋的季节变化和年际变化。结合地面高频海洋雷达、卫星测高、沿海验潮站和海底声学多普勒测流仪的观测结果，还揭示了大豆暖流的季节和年际变化。

Seasonal and interannual variations in the surface circulation of the Sea of Okhotsk including the East Sakhalin Current (ESC) are investigated using ten-year records of the sea level anomaly (SLA) observed by the TOPEX/POSEIDON (T/P) altimeter. The T/P SLA clearly documents seasonal and interannual variations in the ESC along the east coast of Sakhalin Island, although sea ice masks the region from January to April. Estimates of surface current velocity anomaly derived from T/P SLA are in good agreement with drifting buoy observations. The ESC is strong in winter, with a typical current velocity of 30-40 cm/s in December, and almost disappears in summer. Southward flow of the ESC is confined to the shelf and slope region and consists of two velocity cores. These features of the ESC are consistent with short-term observations reported in previous studies. Analysis of the ten-year records of T/P SLA confirms that the structure of the ESC is maintained each winter and the seasonal cycle is repeated every year, although the strength of the ESC shows large interannual variations. Seasonal and interannual variations in the ESC are discussed in relation to wind-driven circulation in the Sea of Okhotsk, using wind stress and wind stress curl fields derived from European Centre for Medium Range Weather Forecasts (ECMWF) reanalysis data and a scatterometer-derived wind product. Seasonal and interannual variations of the anticyclonic eddy in the Kuril Basin are also revealed using T/P SLA. Combining the observations by ground-based High frequency (HF) ocean radar, satellite altimetry, coastal tide gauge stations, and a bottom-mounted acoustic Doppler current meter (ADCP), seasonal and interannual variations of the Soya Warm Current is also revealed.