A Comparison of Characteristics between the Subtropical Countercurrent, the North Equatorial Current and the North Equatorial Countercurrent in the Northwestern Pacific Ocean

According to the geostrophic current calculated from the hydrographic data of temperature and salinity at section 137°E during the winters and summers of 1967～1995, the drift trajectories of drifting buoies which were deployed at 144°E observed by satellites and together with the distributions of surface geopotential anomaly obtained from CSK Atlas, a comparison of the similarities and dissimilarities of the characteristics between the Subtropical Countercurrent (SCC), the North Equatorial Current (NEC) and North Equatorial Countercurrent (NECC) in the Northwestern Pacific Ocean is made in this paper.The main results are concluded as follows: (1) The SCC, NEC and ENCC have the features of multi branch. (2) They all appear at the surface or subsurface with banded current structure, and the eastward and westward currents occurring alternatively. (3) In regard to annual mean velocity of these three currents, the NECC is the strongest current, the NEC is the next one and the SCC is the weakest one. However, the variations of their volume transports are quite different. The largest one is the NEC, the next one is the NECC and the smallest one is SCC. The current speed of three currents in summer is highev than that in winter, but the variations of their volume transports are little bit different, the volume transports of the SCC and the NEC are strong and weak in summer and in winter, respectively; those of the NECC are opposite. (4) During winter, the original area of the SCC is located at Bazel strait and near the center of "Warm Ridge" of the subtropical ridge east of Taiwan Island. (5) The drift trajectories of satellite drifting buoies in winter basically show the paths of the NEC and the NECC, however, it is difficult to demonstrate the path of the SCC in the area where eddies occurred frequently