摘要
在夏季北冰洋的无冰海域,经常可以观测到次表层暖水现象,即在水深20～50m的范围内发生海水温度的极大值。建立了一个一维的热力学解析模式,用于研究夏季北冰洋次表层暖水的形成机制。模式的计算结果表明,太阳辐射作用是形成次表层暖水的关键因素。在北冰洋的开阔水域,大气吸收海洋热量的过程导致了海面温度下降,使温度极大值出现在次表层。海洋垂向湍流热扩散对次表层暖水温度有显著影响;当湍流热扩散较弱时,热扩散的范围较小,有利于形成次表层暖水。次表层暖水的位置随着时间的推移不断加深,温度不断增高。在北极,大气温度低于海面温度是普遍现象,次表层暖水经常发生。虽然当海面气温发生变化时,次表层海水温度结构会发生相应的变化,但次表层暖水结构形成之后,如果不受强烈天气过程的破坏,则会一直存在下去。按照本文的结论,随着北极气候变暖,海冰将进一步减少,次表层暖水现象还会明显增加,海洋对气候变化将有更加强烈的响应和反馈,对全球气候变化产生意义深远的影响。
The subsurface warm water has been observed frequently in the summer ice-free sea area of the Arctic Ocean, that is, a temperature maximum occurred in water depths of 20 to 50 m. In this paper, an one-dimensional analytic thermodynamic model is developed to study the formation mechanism of the subsurface warm water. It is shown from the calculated results that the solar radiation heating plays a key role in forming the subsurface warm water. In the open sea area of the Arctic Ocean in summer, the oceanic heat is absorbed by the air near sea surface to result in the drop in sea surface temperature and the subsurface temperature maximum. The vertical turbulent heat diffusion has significant influence on the subsurface warm water temperature, and the weak turbulent heat diffusion reduces the heat diffusion range to facilitate the formation of subsurface warm water so that the depth and temperature of subsurface warm water increase with the lapse of time. In the Arctic Ocean, the air temperature is often lower than the sea surface temperature, so the subsurface warm water occurs frequently. The relevant changes in surface temperature structure will take place along with the changes in surface air temperature, but the subsurface warm water structure will persist until it is destroyed by strong weather process. It is concluded from this study that the sea ice is supposed to further decrease along with the climatic warming in the arctic region, and the phenomena of subsurface warm water will remarkedly increase, in turn, the strong response and feedback of the ocean will cause significant impact on the global climatic changes.
出处
《海洋科学进展》
CAS
CSCD
北大核心
2004年第2期130-137,共8页
Advances in Marine Science
基金
国家自然科学基金资助项目--北冰洋多年变化及其机理的综合研究(49876008)
关键词
北冰洋
次表层暖水
海冰边缘区
温度结构
太阳辐射
Arctic Ocean
subsurface warm water
marginal ice zone
temperature structure
solar radiation
