北冰洋水体对格陵兰海混合增密对流的可能影响分析

史文奇; 赵进平

北冰洋水体对格陵兰海混合增密对流的可能影响分析

中国海洋大学海洋环境学院, 山东青岛 266100

基金项目: 国家自然科学基金(40876006;40631006)。

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出版历程
- 收稿日期: 2012-02-20
- 修回日期: 2012-05-12

Analysis of possible effects of various water masses in Arctic Ocean to Greenland Sea isopycnal cabbeling convection

Key Laboractory of Physical Oceanography, Ministry of Education, Ocean University of China, Qingdao 266100, China

摘要

摘要: 格陵兰海内发生的等密度混合后产生的增密对流是重要的对流现象之一。北冰洋正在发生快速变化,其内水团变性以及环流系统的改变都将使格陵兰海等密度混合对流发生明显变化,继而对全球气候变化产生影响。以往关于等密度混合对流的研究很少,大都集中在对流发生海域。由于等密度混合的主体是大西洋回流水与北冰洋流出水体,本文目的是探讨北极内部不同海域的水体会对混合增密对流造成的可能影响。文中定义了有效对流速度,强调水平温度梯度和垂向层化强度是影响有效对流速度的决定性因素;水平温度差越大,垂向层化越弱,产生的对流越强。发生在东格陵兰极锋处的有效对流都是大西洋的水体,一部分是在格陵兰海回流的大西洋回流水;一部分是在北冰洋潜沉并回流的北极大西洋水,该水体在北冰洋循环的时间越长,温度差越大,产生的有效对流越强。而横越北冰洋的太平洋水因密度过低而不能参与等密度混合对流,加拿大海盆主盐跃层之上的水体也都不能参与对流。北冰洋几个海盆深层水的温度差异明显,有可能与格陵兰海深层水形成有效对流;但是,由于深层水流速低、湍流混合弱、水平温度梯度小,是否可以产生有效对流尚不清楚。
- 混合增密对流 /
- 北冰洋 /
- 格陵兰海 /
- 东格陵兰极锋 /
- 有效对流速度
Abstract: In Greenland sea,the convection produced by isopycnal cabbeling is an important type of convection. The Arctic Ocean is experiencing intense and rapid changes, in which the changes of water masses and circulation system will alter isopycnal cabbeling convection of Greenland Sea, and further affect the Global climate system. Previous researches on isopycnal cabbeling convection are few, most of them focus on convective regions. As in Greenland Sea,Recirculating Atlantic Water and water masses from Arctic Ocean are the main water masses that involved in the cabbeling convection, so the purpose of this paper is to discuss the possible effects of various water masses in different regions of Arctic Ocean to Greenland Sea cabbeling convection. In this paper, effective cabbeling convection velocity is defined. It's emphasized that horizontal temperature gradient and vertical stratification intensit is determinant to cabbeling velocity. And greater temperature gradient and weaker stratification intensity will lead to intenser convection. In Greenland sea, various water masses involved in the isopycnal cabbeling convection all originate from Atlantic Ocean. Some of them are Recirculating Atlantic Water recirculating in Greenland Sea, the others are Atlantic Water of Arctic which experience recirculating and diving in Arctic Ocean. If the later water masses stay in the Arctic Ocean longer, the temperature gradient will be greater, and the convection will be intenser. While, the water masses from Pacific Ocean which cross the Arctic Ocean could not be involved in isopycnal cabbeling convection for its low density. In the Arctic Mediterranean, deep-water temperature varies between the different basins, so these deep water masses may produce Effective Cabbeling Convection through mixing with Greenland Sea Deep Water. But in the deep and bottom layer of ocean, the current velocity is low, turbulent mixing is weak and temperature gradiant is small, so at present it's not sure whether the convection exists.
- isopycnal cabbeling convection /
- Arctic Ocean /
- Greenland Sea /
- East Greenland Polar Front /
- effective cabbeling convection velocity

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