CAJ | 학술논문

长江冲淡水对黄海、东海水文环境有重要影响，它主要以羽状形态向外海扩展，在某些年份的特殊时间段也存在孤立的低盐水团现象。在低盐水团的动力机制研究中，风、径流量、台湾暖流、天文潮和斜压不稳定的作用已得到讨论。天文潮对冲淡水及低盐水团的影响主要包括潮致余流和潮混合，潮致余流作用仍缺乏讨论。本文对1983年8月低盐水团的动力机制进行数值模拟分析，重点讨论了潮致余流和潮混合的影响。结果表明：潮致Lagrange余流促使一部分冲淡水从口门向北输运，在32°N附近呈舌状转向东，有利于在口外东北海域形成低盐水团；小潮转大潮的垂向混合作用加强，浅水区表层盐度升高的速度快于较深水区，也有利于在口外东北海域形成低盐水团。
장강충담수대황해、동해수문배경유중요영향，타주요이우상형태향외해확전，재모사년빈적특수시간단야존재고립적저염수단현상。재저염수단적동력궤제연구중，풍、경류량、태만난류、천문조화사압불은정적작용이득도토론。천문조대충담수급저염수단적영향주요포괄조치여류화조혼합，조치여류작용잉결핍토론。본문대1983년8월저염수단적동력궤제진행수치모의분석，중점토론료조치여류화조혼합적영향。결과표명：조치Lagrange여류촉사일부분충담수종구문향북수운，재32°N부근정설상전향동，유리우재구외동북해역형성저염수단；소조전대조적수향혼합작용가강，천수구표층염도승고적속도쾌우교심수구，야유리우재구외동북해역형성저염수단。
The expansion of the Changjiang diluted water (CDW) is a dominant hdrographic phenomenon in the East China Sea ,which is mainly in the shape of plume .However ,there are some low salinity water lenses (LSWL) in partial time of some years .The effects of wind ,runoff ,Taiwan Warm Current ,tide and baroclinic instability on LSWL have been discussed in the previous studies .Tide induced residual current and tidal mixing may both make effect on CDW and LSWL ,but there are lack of discussions on the former .In this paper ,some numerical simula-tions are made to analyze the dynamic mechanism of LSWL in August 1983 ,and more discussions are put on the effects of tide induced residual current and tidal mixing .Tide induced Lagrange current drove part of CDW north-ward from the river mouth ,then turned it eastward in the shape of tongue near 32°N ,which was helpful for forming LSWL in the northeast out of the estuary .Tidal vertical mixing strengthened from neap tide to spring tide ,the sur-face salinity at the shallow water increased faster than that at the deep water ,which was also helpful for forming LSWL in the northeast out of the estuary .