| 摘要: |
| 上升流即海洋中持续垂直向上的海水运动,这种运动在海洋中是比较普遍的,但是，就其大小而言,却有着巨大的差异——可达几个数量级。所以,只有在那些量值较大的区域才引起人们的注意;而在量值较小的区域由于表象不够显著——对各种特征场特别是温度场的影响不太明显,往往被人们所忽视。
尽管上升流的流速与水平流速相比甚小,一般在10-5-10-2厘米/秒范围内(大约相当于每天1厘米至10米),但其作用却是巨大的。首先,就整个海洋来说,它是海洋环流不可分割的一个组成部分,是上层水与下层水沟通交换的渠道。其次，上升流在生产实践中具有十分重要的意义,它对渔业生产有着巨大的影响,它能将富含营养盐的中、下层水带到强光合作用层,为浮游植物提供充分的养料,从而促进鱼类佴料的繁殖。海洋中出现上升流的区域仅占世界整个海洋面积的1‰左右,但上升流区的渔获量却占全世界总产量的50%左右；我国浙江近海、海南岛东南水域以及汕头外海诸上升流区同时均为良好渔场。因此,沿岸上升流越来越引起人们的重视。
从现有文献来看,我国近海。在渤海、黄海、东海和南海四个海区都有上升流存在,如渤海中部、黄海冷水团区、浙江近海、汕头外海以及海南岛东南沿海等。但是,关于这一现象,除少数海洋工作者曾提及过外,至今还缺乏专门的研究。
本文旨在利用现有的海流、水温、盐度和气象资料,就浙江沿岸(见图1)上升流产生的动力来源及环流模式进行初步的分析研究,提出粗路估算上升流的方法、指标,并提出尚待进一步解决的几个问题。所用资料主要是1958-1960年全国海洋普查、1963-1966年标准断面以及我所六十年代以来(到1973年)观测的有关资料。此外,还用了国家海洋局和浙江省气象局所提供的部分海流资料及沿岸合站的水文气象资料。 |
| 关键词: 上升流 成因 动力结构 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院海洋研究所调查研究报告第661号 |
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| ON THE CAUSE AND DYNAMICAL STRUCTURE OF THE COASTAL UPWELLING OFF ZHEJIANG PROVINCE |
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Hu Dunxin, Lu Lianghong, Xiong Qingcheng, Ding zongxin, Sun Shouchang
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Institute of Oceanology, Academia Sinica
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| Abstract: |
| In the present paper the cause and dynamical structure of the coastal upwelling taking place off Zhejiang Province is discussed. The section distribution of water temperature measured in the area is a clear evidence of the existence of upwelling.To verify whether the upwelling here is mainly caused by the northward branch of the Kuroshio or by wind, the vertical velocities of the two are calculated separately,from data on both bottom currents and wind stresses collected in June-july of 1959 and 1963 respectively. The vertical velocity computed from current measurements near the bottom is one order larger than computed from wind stress. That means, in summer
time, the major component of upwelling off Zhejiang Porvince is “nonwind-driven”.
In order to show the numerical relationship between the intensity of the coastal upwelling in the area and of the northward branch of the Kuroshio, the correlation analysis is made between the temperature and the salinity on the basis of data of six summers.
A new method to calculate vertieal velocity of water is suggested in the paper. |
| Key words: the cause and dynamical structure the coastal upwelling |
