The study on the monitoring of oceanic condition in the East China Sea

我们研究计划的目的是估计在大范围调查区域长达一个月的巡航期间获得的海洋数据中的拍摄周期和小尺度变化分量，并利用生物地球化学示踪剂阐明当前的水团系统和分布机制。主要研究结果如下：1.研究成果。短周期和小空间尺度的变化(1)在110m深的大陆架上，通过相距15公里、相距15公里、相距55小时的17个周期测量，得到了包括生物地球化学示踪(营养物等)在内的水质三维分布的潮汐周期变化。(2)通过近10天沿横跨黑潮锋面的大陆架断裂附近的短线重复多次观测，发现低盐度水潜入黑潮水中层的时间尺度仅为几天。(3)通过在黑潮或陆架区同一测站相隔5~10天的观测，我们发现水性的巨大变化伴随着黑潮的变化。2.水团的识别和追踪(1)通过在大陆架和黑潮地区进行四次站距较小的广域调查，我们得到了详细的水性和水流的三维分布。(2)找到了非保守性物质，如颗粒有机物(碳、氮)、叶绿素、营养盐、氧，以及用荧光细胞仪区分的三种微浮游动物群落的数量，可用于水团的判别和运动跟踪。(3)发现盐度和溶解氧略低于黑潮水的水体在外大陆架上占据了相当大的面积。

The objectives of our research program are to estimate the shot-periods and small-scale variation components in the oceanographic data obtained during about one-month long cruise in wide survey area, and to elucidate the current system and distribution mechanism of water mass by using the biogeoche-mical tracers. The major results are as follows.1. Short-periods and small-spatial scale variations (1)By the 17 cyclic surveys for 55 hours running around 3 points ca 15 km apart over the continental shelf of 110 m depth, we have obtained the tidal period variations of 3-D distributions of water properties including biogeochemical tracers (nutrients etc.). (2)By the surveys repeated several times during about 10 days along short lines crossing the Kuroshio front near the continental shelf break, we have found the time scale of low salinity water subduction into the middle layer of Kuroshio Water to be only a few days. (3)By the surveys 5 to 10 days apart at same stations in the Kuroshio or continental shelf region, we have found the large variation of water properties to be accompanied with the variation of Kuroshio.2.Discrimination and tracking of water masses (1)By the four wide area surveys with fine station spacing over the continental shelf and the Kuroshio regions, we have obtained the detailed 3-D distributions of water properties and currents. (2)We have found the non-conservative materials such as particulate organic matter (carbon and nitrogen), chlorophyll, nutrients, and oxygen, and each amount of three communities of picoplankton discriminated by fluocytometer to be utilized in the discrimination of water masses and tracking their movements as the indicators. (3)We have found that the water mass of which salinity and dissolved oxygen are slightly lower than the Kuroshio Water, occupies the rather wide area over the outer continental shelf.