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利用“长风丸”调查船在1987年9～10月期间得到的水文资料,对东海黑潮与琉球群岛以东海流进行了半诊断计算.本计算分为两个阶段,第一阶段是诊断的,第二阶段取诊断计算结果作为初始值,进行半诊断计算,即调整阶段.计算表明,当T=30～40d时,密度场与速度场等已被调整,即得到了半诊断计算的解.比较诊断与半诊断的两个计算结果,在定性上它们是基本一致的,但在定量上存在一些重要差别,例如以下几点:（1）由于诊断计算采用了平滑后的资料,两支西边界流,即黑潮及琉球群岛以东西边界流（简称“琉球海流”）的流速计算值都偏低.而通过调整后的半诊断计算,这两支西边界流的流速都加强;（2）半诊断计算密度场等已被调整到与海底地形等相适应.例如东海黑潮流速的最大值为101cm/s,出现在东海海区南部最大的地形坡度处,而诊断计算,由于资料平滑,没有得到这样的结果;（3）在琉球群岛以东海域,在最近岛屿处600m以浅水层,诊断计算结果出现了南向流,这也是由于资料平滑所致.然而,半诊断计算结果在此处出现了北向流,这与观测结果是一致的.这些计算结果都表明,当采用平滑后的资料时,应用半诊断模式计算海流,更为适宜.
Hydrological data obtained from Changfengwan survey ship from September to October 1987 were used to make a semi-diagnostic calculation of the Kuroshio in the East China Sea and the sea flow to the east of the Ryukyu Islands.This calculation is divided into two stages, the first stage is the diagnosis , The second stage takes the result of diagnosis as the initial value and carries out semi-diagnosis calculation, that is, the adjustment stage.The calculation shows that when T = 30 ~ 40d, the density field and velocity field have been adjusted to obtain the semi-diagnostic calculation Solution. Comparing the two results of the diagnosis and the semi-diagnosis, they are basically the same qualitatively, but there are some important differences in the quantification, for example, the following points: (1) Since the diagnostic calculation uses the smoothed data, The calculated values of flow velocity in the western border flows, that is, the Kuroshio and Ryukyu Islands to the east and west boundary flows (Ryukyu currents) are low, and the flow rates of the two western boundary flows are all strengthened by the adjusted semi-diagnosis calculation. (2) Semi-diagnostic calculation The density field has been adjusted to match the seafloor topography, etc. For example, the maximum value of the Kuroshio velocity in the East China Sea is 101cm / s, which appears at the largest terrain gradient in the southern part of the East China Sea. However, Smooth, did not get (3) In the area to the east of the Ryukyu Islands, a shallow flow at a depth of 600 m to the nearest island resulted in a southward flow of diagnostic results due to the smoothing of data, however, the results of semi-diagnostic calculations appear here The northward flow, which is consistent with the observations, shows that it is more appropriate to apply the semi-diagnostic mode to ocean currents when using smoothed data.