Comparative Analysis of Jet Detection Methods on the Basis of Satellite Altimetry Data by Example of the Antarctic Circumpolar Current Sector to the South of Africa
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Abstract—
For the period of satellite altimetry observation 1993–2018, a comparison was made of estimates of the linear meridional shifts of the jet structure and variations in current intensity in the sector of the Antarctic Circumpolar Current (ACC) south of Africa (10° E–25° W), obtained on the basis of the parameters derived from the module of the absolute dynamic topography (ADT) gradient \(\left| {\nabla \zeta } \right|\): directly \(\left| {\nabla \zeta } \right|\), module of the velocity of geostrophic current |u| on the ocean surface, half of square of the ADT gradient \(\frac{1}{2}{{\left| {\nabla \zeta } \right|}^{2}}\), and specific kinetic energy \(\frac{1}{2}{{u}^{2}}\). The analysis was carried out by a method developed earlier and refined in this paper using linear regression analysis. It is shown that qualitatively the characters of the meridional shifts (displacement of the curves of these parameters averaged over latitude and for each year) in latitude and the corresponding current intensity variations (i.e., variations in the parameters themselves) over 26-year observations, when calculated through each of the four parameters, turned out to be similar. The same similarity was obtained from the calculations with respect to the ADT scale. Meanwhile, the quantitative differences between calculations for different pairs of parameters can be significant even in the \(\left| u \right|\) and \(\left| {\nabla \zeta } \right|\) pair. In quantitative terms, the absolute values of shifts of the jet structure and variations in the intensity of currents in the ACC band in the studied sector of the Southern Ocean generally increase from those linearly dependent on the ADT gradient module to quadratically dependent ones.
摘要-在1993-2018年卫星测高观测期间，比较了非洲以南（东经10°-西经25°）南极环极洋流（ACC）扇区喷流结构线性经向移动和洋流强度变化的估计值，这些估计值是根据绝对动态地形（ADT）梯度模块得出的参数\(\left| {\nabla \zeta } \right|\)得到的：direct \(\left| {\nabla \zeta } \right|\), module of the velocity of geostrophic current |u| on the ocean surface, half of square of the ADT gradient \(\frac{1}{2}{\left| {\nabla \zeta } \right|}^{2}}\), and specific kinetic energy \(\frac{1}{2}{{u}^{2}}\)。分析采用了早先开发并在本文中改进的线性回归分析方法。结果表明，在 26 年的观测中，通过四个参数的计算，纬度上的经向移动（这些参数的曲线位移在纬度上的平均值和每年的平均值）和相应的海流强度变化（即参数本身的变化）的定性特征是相似的。ADT 尺度的计算结果也是如此。同时，即使在 \(\left| u \right|\)和 \(\left| {\nabla \zeta } \right|\)参数对中，不同参数对的计算结果在数量上的差异也是显著的。In quantitative terms, the shifts of the jet structure and variations in the intensity of currents in the ACC band in the studied sector of the Southern Ocean generally increase from those linearly dependent on the ADT gradient module to quadratically dependent ones.
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Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance.
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