极地研究

极地研究 ›› 2019, Vol. 31 ›› Issue (3): 231-245.DOI: 10.13679/j.jdyj.20190015

• 研究论文 •    下一篇

1980-2015年夏季南大洋亚南极锋和极地锋的长期变化研究

权陕媛 史久新   

  1. 中国海洋大学海洋与大气学院, 山东 青岛266100
  • 收稿日期:2019-03-18 修回日期:2019-04-27 出版日期:2019-09-30 发布日期:2019-09-30
  • 通讯作者: 权陕媛
  • 基金资助:

    国家重点研发计划项目(2018YFA0605701)资助

Study on the long-term variability of Subantarctic and Polar Fronts in austral summer during 1980-2015

Quan Shanyuan, Shi Jiuxin   

  • Received:2019-03-18 Revised:2019-04-27 Online:2019-09-30 Published:2019-09-30
  • Contact: Shanyuan Quan

PDF (PC)

688

摘要：

本文利用再分析月均海洋温盐数据, 分别采用基于物理现象和固定温盐量值的锋面识别标准, 探究1980—2015年夏季(1—3月)亚南极锋(Subantarctic Front, SAF)和极地锋(Polar Front, PF)的变化特征。对此时段的长期变化, 两类标准给出了基本一致的结果。在绕极平均意义上, SAF和PF的位置虽然存在南北向摆动, 但是在1980—2015年并没有显著的长期移动趋势。在整个空间场上, 锋面的位移幅度、稳定性和长期移动趋势均有明显的区域差异性, 在经过大的地形障碍区时, 锋面较稳定, 位移幅度较小, 而在深海盆区和脱离地形约束的下游, 锋面稳定性较低, 且经向位移幅度较大。SAF和PF稳定性最高、长期移动趋势最小的区域分别位于印度洋扇区和大西洋扇区。SAF在太平洋扇区的东部海盆区有较显著的长期移动趋势, 且南北向位移均存在, PF在印度洋扇区以向极移动为主。在年代和年际尺度上, 两类标准给出的结果存在一定的差异, 进而分别对两类识别标准的适用性进行了讨论。对于PF来说, 温度现象类标准总体上稳定性更高, 优于等温线标准。

关键词: 亚南极锋, 极地锋, 长期变化, 南大洋

Abstract:

The variability of the Subantarctic Front (SAF) and Polar Front (PF) in austral summer (January–March) during 1980–2015 was investigated using monthly mean potential temperature and salinity reanalysis data, and by applying criteria based on physical phenomena and fixed property values to frontal detection. The results derived from two types of criterion were consistent with each other regarding the long-term trend of frontal position during the 36–year period. In terms of circumpolar average, no significant trend of frontal movement was found between 1980 and 2015, although frontal variability appeared as fluctuation during these years. The migration amplitude, stability and long-term trend of the fronts showed regional differences. Minimal displacement and high stability were found in regions with large topographic obstacles, whereas the fronts move significantly and frequently in deep basins and downstream of obstacles. The regions with the highest stability and the smallest long-term movement of the SAF and PF were found in the Indian and Atlantic sectors, respectively. In the eastern Pacific sector, the SAF showed significant long-term movement with both northward and southward shifts, whereas southward displacement of the PF dominated the Indian sector. On decadal and interannual timescales, evident differences were found between the results of frontal detection derived from the two criteria; thus, the applicability of both criteria was discussed accordingly. For the PF, the criterion based on the temperature phenomenon was found more stable than the isotherm criterion.

Key words: Subantarctic Front, Polar Front, long-term variability, Southern Ocean