Convective instability in the bottom of Northern South China Sea

QU Ling; GUO Shuangxi; LU Yuanzheng; CEN Xianrong; HUANG Pengqi; ZHOU Shengqi

doi:10.7638/kqdlxxb-2021.0410

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Convective instability in the bottom of Northern South China Sea

更新时间：2026-05-28

- Convective instability in the bottom of Northern South China Sea
- Vol. 40, Issue 2, Pages: 199-207(2022)
- 作者机构：
  
  1. 中国科学院南海海洋研究所，热带海洋环境国家重点实验室,广州,510301
  2. 南方海洋科学与工程广东省实验室（广州）,广州,511458
  3. 中国科学院南海生态环境工程创新研究院,广州,510301
  4. 湖北省地质局地球物理勘探大队,武汉,430056
  5. 佛山科学技术学院工业设计与陶瓷艺术学院,佛山,528000
- 作者简介：
- 基金信息：
- DOI：10.7638/kqdlxxb-2021.0410
  CLC： P731.26
- Published：2022
- 稿件说明：
移动端阅览
屈玲, 郭双喜, 鲁远征, 等. 南海北部底层对流不稳定性研究[J]. 空气动力学学报, 2022, 40(2): 199−207.

QU Ling, GUO Shuangxi, LU Yuanzheng, et al. Convective instability in the bottom of Northern South China Sea[J]. 2022, 40(2): 199-207.
屈玲, 郭双喜, 鲁远征, 等. 南海北部底层对流不稳定性研究[J]. 空气动力学学报, 2022, 40(2): 199−207. DOI： 10.7638/kqdlxxb-2021.0410

QU Ling, GUO Shuangxi, LU Yuanzheng, et al. Convective instability in the bottom of Northern South China Sea[J]. 2022, 40(2): 199-207. DOI： 10.7638/kqdlxxb-2021.0410.

摘要

底层对流不稳定对海洋底层能量输运和湍流混合有重要影响。为评估底层对流不稳定对能量输运的贡献，基于2018年9月20日南海东北部东沙群岛海域（20.8953 °N，117.1808 °E，水深385 m）37 h锚定潜标高时空分辨率观测数据，对观测站位海洋底层水体的温度结构特征进行了分析，研究了对流底层厚度变化，及其对海洋底层能量输运和湍流混合的贡献。结果表明，观测站位对流底层出现的概率约为总观测时间的56%，其厚度平均值为6.17 m。底层平流为下坡流时，对流底层出现的概率约为50%，其厚度相对较小，均小于10 m；而为上坡流时，对流底层出现的概率约为70%，其厚度显著增大，可达到40 m。对流不稳定驱动的垂向热通量

和传热效率

具有间歇性特征，观测时间内

平均值为0.41 W/m

，

平均值为249.91，且对流热通量远高于底层流速剪切通量。对流底层湍流热扩散率和涡扩散率的评估结果表明，随着底层湍流混合强度的增强，对流不稳定对底层湍流混合的贡献率逐渐减小。

Abstract

The unstable convection of the ocean floor has a significant influence on the energy transport and turbulent mixing at the ocean bottom. In order to estimate the contribution of the unstable convection to the energy transport

an oceanographic survey was undertaken at a site near the northeast of the Dongsha Atoll in the South China Sea (20.8953°N

117.1808°E

ocean depth of 385 m). The characteristic of temperature structure and the variations of convection layer’s thickness in the ocean bottom boundary layer were studi

which is based on the 37-h observed hydrologic data. The contribution of unstable convection to the transportation of energy and the turbulent mixing was investigated. Research shows that

for the whole observational period

the time fraction unstable layer was about 56%

and its mean thickness was 6.17 m. During the down-slope phase

the percentage of unstable layer’s presence was about 50% with mean thickness smaller than 10 m

while during the up-slope phase

its presence percentage was about 70%

and its thickness reached as large as 40 m. The vertical heat flux introduced by unstable convection

and the heat transfer efficiency

appeared occasionally

with mean

as 0.41 W/m

and mean

as 249.91. The heat flux of convection was much higher than the bottom velocity shear flux. The results indicated that the contribution of unstable convection to the turbulent mixing decrease gradually with enhancement of the bottom turbulent mixing.

关键词

Keywords

references

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