极地研究

极地研究 ›› 2018, Vol. 30 ›› Issue (4): 370-375.DOI: 10.13679/j.jdyj.20180005

• 研究论文 • 上一篇    下一篇

南极威德尔海西北区域的冰-气拖曳系数和脊帆形拖曳力分析

谭冰1,2  张新刚1  王骁力1  卢鹏2  李志军2   

  1. 1. 南阳师范学院数学与统计学院, 河南 南阳 473061;
    2. 大连理工大学海岸和近海工程国家重点实验室, 辽宁 大连 116024
  • 收稿日期:2018-02-22 修回日期:2018-05-26 出版日期:2018-12-30 发布日期:2018-12-30
  • 通讯作者: 谭冰
  • 基金资助:

    国家自然科学基金(41876219, 41376186)、河南省高等学校重点科研项目(19A110029)和科技攻关项目(172102310702)资助

Ice–air drag coefficient and form drag on ridge sails in Northwestern Weddell Sea, Antarctica

Tan Bing1,2   Zhang Xingang1   Wang Xiaoli1  Lu Peng2  Li Zhijun2   

  • Received:2018-02-22 Revised:2018-05-26 Online:2018-12-30 Published:2018-12-30

PDF (PC)

725

摘要：

基于机载激光高度计测得的南极威德尔海西北区域冬季海冰表面起伏数据, 结合脊帆形态参数和空间分布对中性条件(大气层处于中性平衡态)下对应10 m高度处风速的冰-气拖曳系数Cdn(10)和脊帆形拖曳力Fd的参数化方案进行了改进, 并探讨了冰-气拖曳系数Cdn(10)和脊帆形拖曳力对总拖曳力的贡献随脊帆强度(脊帆高度与间距的比值, 其中脊帆高度是指脊帆顶点到平整冰面的垂直距离, 脊帆间距是指相邻两个脊帆顶点之间的距离)和冰面粗糙长度的变化情况。结果表明, 冰-气拖曳系数Cdn(10)随脊帆强度增大呈递增趋势, 对较小的脊帆强度, Cdn(10)随粗糙长度的增大而增大, 但脊帆强度较大时, Cdn(10)随粗糙长度减小而增大, 即存在某一脊帆强度阈值, 使Cdn(10)在该阈值两侧随粗糙长度的变化趋势相反; 脊帆形拖曳力对总拖曳力的贡献随脊帆强度减小而减小, 随着粗糙长度增大而减小。通过分析发现, 造成以上不同变化趋势的主要原因是: 随着脊帆强度的增大, 摩拖曳力在总拖曳力中的优势地位逐渐由形拖曳力代替。

关键词: 南极, 冰-气拖曳系数, 形拖曳力, 参数化

Abstract:

Using sea ice surface roughness measurements made by a helicopter-borne altimeter in the northwestern Weddell Sea, the formulas to derive ice–air drag coefficient Cdn(10) at a reference height of 10 m under neutral and stable conditions and form drag on ridge sails were improved. Morphological parameters and distributions of ridge sails were incorporated. Variations of Cdn(10) and contribution of form drag on ridge sails to total drag with increasing ridging intensity and roughness length were discussed. Results revealed that Cdn(10) increases with increasing ridging intensity. When ridging intensity is low, Cdn(10) increases with roughness length whereas it decreases with roughness length when ridging intensity is high. The contribution of form drag on ridge sails to total drag increases with ridging intensity and decreases with increasing roughness length, because form drag on ridge sails dominates over skin drag over rough ice surface when ridging intensity becomes extremely large.

Key words: Antarctica, ice–air drag coefficient, form drag, parameterization