极地研究

极地研究 ›› 2018, Vol. 30 ›› Issue (1): 32-41.DOI: 10.13679/j.jdyj.20170018

• 研究论文 • 上一篇    下一篇

双扩散在南极文森湾海域热盐结构演变中的作用

张贤良1,3  程灵巧1,2  高郭平1,2   

  1. 1. 上海海洋大学海洋科学学院海洋科学与技术系, 上海 201306
    2. 上海海洋大学大洋渔业资源可持续利用省部共建教育部重点实验室, 上海 201306
    3. 中国科学院上海技术物理研究所, 上海 200083
  • 收稿日期:2017-06-12 修回日期:2017-08-29 出版日期:2018-03-30 发布日期:2018-03-30
  • 通讯作者: 程灵巧
  • 基金资助:

    国家自然科学基金(41506219)和上海市浦江人才计划(15PJ403000)资助

Effect of double diffusive convection during the evolution of seawater thermohaline structure in Vincennes Bay, Antarctica

Zhang Xianliang1,3, Cheng Lingqiao1,2, Gao Guoping1,2   

  • Received:2017-06-12 Revised:2017-08-29 Online:2018-03-30 Published:2018-03-30
  • Contact: Ling-Qiao CHENG
  • Supported by:

    ;Shanghai Pujiang Program

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摘要：

利用22 头象海豹携带的CTD 观测到的2012 年3—4 月南极文森湾中西部海域的海水温盐剖面数据,
研究了双扩散效应在海水热盐演变过程中的作用。结果显示, 该海域双扩散效应显著, 其中“扩散对流”作
用在水柱中所占比例超过50%, 并普遍存在于500—800 dbar 深度的深层水中; “盐指对流”作用在水柱中
所占比例不超过10%, 存在于300—500 dbar 的中层水中; 随着时间进入南极冬季, 海水结冰盐析过程会使水
体中重力不稳定状态加剧。“扩散对流”会产生向上的热通量和盐度通量, 热通量大约在0.02—0.5 W·m–2, 盐
度通量平均在10–8 m·s–1 左右; “盐指对流”则会产生向下的热通量和盐度通量, 平均热通量约为–0.5 W·m–2,
平均盐度通量约为–10–8 m·s–1。在结冰初期, 文森湾陆架海域的海表结冰过程对低温高盐水体的产生具有补
充作用, 进而通过扩散对流作用使得高密度陆架水(DSW)在水体内部得到补充生长与积累。因此, 双扩散作
用对于该海域高密陆架水的形成有不可忽视的贡献。

关键词: 陆架水, 水体结构演变, 双扩散, 扩散对流, 文森湾, 南极

Abstract:

Based on seal CTD data obtained in mid-western areas of Vincennes Bay during March–April 2012, the
effect of double diffusive convection during the evolution of the seawater thermohaline structure during the
early freezing period was evaluated. Results showed that the effect of double diffusion convection was substantial.
The proportion of “diffusion convection” throughout the entire water column was >50%, and strong
“diffusion convection” persisted in the deep water from 500 to 800 dbar. The proportion of “salt finger convection”
in the water column was ≤10% and it occurred in the mid-layers between 300 and 500 dbar. As the
Antarctic winter progresses, brine rejection during sea ice formation makes the water increasingly gravitationally
unstable. “Diffusion convection” produces upward fluxes of heat and salinity. The heat flux is in the
range of 0.02–0.5 W·m−2, and the average salinity flux is about 10−8 m·s−1. “Salt finger convection” produces
downward fluxes of heat and salinity; the average heat flux is about −0.5 W·m−2 and the average salinity flux
is about −10−8 m·s−1. During the early freezing period, continuous cooling and brine rejection force the production
of dense water with low temperature and high salinity. Double diffusion convection (mainly diffusive
convection) reforms the water properties, making the entire water column denser. Therefore, the contribution
of double diffusion convection on the formation of dense shelf water in Vincennes Bay is crucial.

Key words: shelf water, evolution of seawater, double diffusion convection, diffusive convection, Vincennes
Bay, Antarctica