Abstract

Climatology and variability of anticyclonic (AC-type) and cyclonic (C-type) wave breaking in the region of the subtropical jet stream are investigated using the previously developed method for identifying and clustering Rossby wave breaking events. Potential vorticity at an isentropic surface of 350 K from the ERA-Interim and ERA5 reanalyses are used. The results of applying the methods for the two reanalyses are similar. However, there is a high inconsistency for cyclonic wave breaking events, especially in summer. The maximum for both types of wave breaking is registered in summer. There are two main maximum areas for the AC type: Atlantic and Pacific. A specific feature of the C type is the climatic maximum in East Asia, probably due to the summer development of the East Asian monsoon. The intensity of the AC-type wave breaking for the entire Northern Hemisphere during the year demonstrates a positive trend. Seasonal changes of the AC type were also consistent for the two reanalyses, global changes are less consistent for cyclonic wave breakings, and significant trends are basically absent. The regional analysis revealed that the frequency of AC-type wave breaking in summer decreases over the Eastern Atlantic and increases over Europe. The agreed and possibly related changes in the AC and C types are recorded in the Asia-Pacific. In summer, there is a decrease in the C-type occurrence over East Asia and an increase in the AC-type occurrence over the Eastern Pacific. However, these changes were found only for the ERA-Interim and require further analysis and interpretation.

中文翻译：

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副热带急流区罗斯贝波破碎的长期变率

摘要

使用先前开发的识别和聚类罗斯比波破坏事件的方法研究了副热带急流区域中反气旋（AC 型）和气旋（C 型）波破坏的气候学和变异性。使用来自 ERA-Interim 和 ERA5 再分析的 350 K 等熵表面的位涡度。应用这两种方法进行再分析的结果是相似的。然而，气旋波破坏事件存在高度不一致，特别是在夏季。两种类型的波浪破坏的最大值都在夏季记录。AC 类型有两个主要的最大区域：大西洋和太平洋。C型的一个具体特征是东亚的气候最大值，可能是由于东亚季风的夏季发展。全年整个北半球的交流型破波强度呈现积极趋势。两次再分析AC类型的季节变化也一致，气旋波断裂的全球变化不太一致，基本不存在显着趋势。区域分析表明，夏季交流型波浪破坏的频率在东大西洋减少，在欧洲增加。AC 和 C 类型的商定和可能相关的变化记录在亚太地区。夏季，东亚C型出现减少，东太平洋AC型出现增加。然而，这些变化仅在 ERA-Interim 中被发现，需要进一步分析和解释。