Abstract The surface circulation of the Ionian and Adriatic Seas is explored by the re-analysis of available datasets that estimate the mean monthly ocean state for the 60 years-long time period 1955-2015. Emphasis is given to the major recurrent and transitional events in the area. Two circulation indices are utilized for the quantification of the cyclonic or anticyclonic circulation modes and intensity, one based on the vorticity flux of the reconstructed mean monthly surface velocity field, and another based on an appropriately modified version of the velocity field. Such quantification consequently allows for a detailed analysis of the surface circulation variability for the entire Ionian and Adriatic basins, as well as for sub-regions of particular interest. Discontinuities associated with possible regime shifts of the examined flow field were identified by time-series analysis of the circulation indices and compared to well-documented events in the hydrography of the studied area. Subsequently, the statistically significant components of the surface circulation variability were resolved out of a red noise background in the time-frequency domain and their evolution was studied. The results highlight the presence of various circulation modes and reversals in different temporal scales (mainly seasonal and decadal to inter-decadal) which are discussed in reference to the dynamics of both the sub-regional (Western, Northern, Eastern, and Southern Ionian, as well as Northern and Southern Adriatic), and of the basin-wide (Ionian or Adriatic) spatial scales. The relationships of the surface circulation variability between the Ionian and the Adriatic basins are also assessed through wavelet coherence.

中文翻译：

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爱奥尼亚-亚得里亚海的海面环流变化

摘要 爱奥尼亚海和亚得里亚海的表面环流是通过对现有数据集的重新分析来探索的，这些数据集估计了 1955 年至 2015 年 60 年间的月平均海洋状态。重点是该地区的主要经常性和过渡性事件。两个环流指数用于量化气旋或反气旋环流模式和强度，一个基于重建的月平均表面速度场的涡量通量，另一个基于速​​度场的适当修改版本。因此，这种量化允许对整个爱奥尼亚和亚得里亚海盆地以及特别感兴趣的子区域的地表环流变化进行详细分析。通过环流指数的时间序列分析确定了与所检查流场可能发生的状态变化相关的不连续性，并与研究区域水文中记录良好的事件进行了比较。随后，地表环流变率的统计显着分量从时频域中的红噪声背景中分辨出来，并研究了它们的演变。结果突出了不同时间尺度（主要是季节性和年代际到年代际）的各种环流模式和逆转的存在，这些循环参考了次区域（西部、北部、东部和南部爱奥尼亚、以及北部和南部亚得里亚海），以及整个盆地（爱奥尼亚或亚得里亚海）的空间尺度。