在近岸海区,海流主要包括潮流和余流。前者是在月球和太阳引潮力作用下所产生的周期性水体运动,流向基本与涨落潮出入河口区的方向相一致;后者则是在水文气象条件作用下所产生的非周期性水体运动,流向虽随季节或其它因素的改变而有一定差异,但相对比较定常。 In the coastal area, the ocean currents mainly include tidal current and residual current. The former is the periodic water movement produced by the tidal force of the moon and the sun, and the flow direction is basically consistent with the direction of the ebb and tail of the estuary; the latter is the non-periodic water movement produced under the hydrological and meteorological conditions , Although the flow direction changes with the seasons or other factors have some differences, but relatively more regular.