磨刀门水道具有垂向间断和连续结构的盐水楔

通过在珠江河口磨刀门水道中盐度和流速的垂精细观,第一次证实了磨刀门水道中盐水楔存在垂间断和连续分的典型结构,并发现盐水楔的结构与河口潮涨潮落的流动紧密相关联.小潮与大潮时的盐水都是高度的,但盐水楔垂结构同.小潮期间盐水楔长时间存在有垂间断面的结构,流动基本上为两流,出现较长时间的上落、下涨的流动现,且盐水的上溯能力强.大潮期间盐水楔有明显的进退,但涨潮时和落潮时的盐水楔结构完全同.涨潮时盐水楔现垂盐度有间断面的结构,下高盐水区涨潮流速大于上流速;落潮转流出现时盐度的垂间断面溃灭,盐水楔现垂盐度连续变化的结构,对应落潮流速为表流速大、底流速小,流速的垂变化是连续的;大潮盐水楔结构变化明显,但盐水上溯能力较弱.

Salt wedge with vertical structure of discontinuous and continuous distribution in modaomen waterway

The typical structure that vertical discontinuous and continuous distribution exist in the salt wedge of Modaomen waterway is firstly proved through the data from the subtitle observation on vertical salinity and velocity in Modaomen waterway of Pearl River.And the close relationship between the internal structures of salt wedge and tidal flow in estuary is also firstly proved.During the spring tide and neap tide,the saltwater is almost highly stratification,but the structures of salt wedge are different from each other.During the neap tide the salt wedge lasts a long time with vertically discontinue structure and the flow is divided into two layers.The upper layer flows seaward while the lower layer flows landward for quite a long time.The saltwater can run upstream a long way during the neap tide.During the spring tide the movement of salt wedge can be seen clearly but the structure of salt wedge during the flood is completely different from the one during the ebb.During the flood time the salt wedge has a vertically discontinue structure and the velocity of the lower high saltwater is greater than that of the upper layer.While during the ebb time the vertically discontinue structure of the salt wedge disappears and the vertical structure becomes continuous.The corresponding surface velocity is larger than bottom velocity and the vertical velocity structure is continuous.During the spring tide the changes of the salt wedge structure are significant but the saltwater runs a shorter way than that during the neap tide.