Abstract Turbulent kinetic energy dissipation rates and vertical diffusivities in the Indonesian seas are inferred from historical CTD measurements gathering for the first time data from Indonesian and international cruises. Dissipation rates are inferred from the CTD using an improved Thorpe scale method, which is validated against microstructure measurements. Elevated dissipation rates ~[10−6–10−7] m2 s−3, were observed in the near field stations, such as in the straits, narrowing passages and shallowing topography where internal tides are generated and Indonesian throughflow (ITF) is intense, while lower dissipation rates ~[10−8–10−10] m2 s−3 were observed in the far field stations and below the pycnocline. The main mixing hot spots are located in the Labani Channel and shallowing topography of the Dewakang waters for the western route of ITF, i.e. the passage that connects the north Pacific source via Sulawesi Sea, Makassar Strait and Flores Sea; in the straits of Halmahera, Lifamatola, and Buru for the eastern route of ITF, i.e. the passage that connects the south Pacific source via Halmahera Sea, Maluku Sea, Seram Sea; and in the ITF exit passages, i.e. the Lombok, Sape and Ombai Straits. The eastern route is more dissipative than the western route, which is consistent with the stronger erosion of the salinity peak of the Pacific waters along the eastern route. We found that tidal variations influence the dissipation rates and diffusivities as has been suggested from the yoyo profiling datasets. The spatial pattern of dissipation rates inferred from the high-resolution 3D hydrodynamics model output of Nagai and Hibiya (2015) shows a general agreement with the observations in the location of the mixing hot spots and suggests that the M2 internal tide is the dominant factor driving the turbulent kinetic energy dissipation rates in the Indonesian seas. Yet the model also shows a bias toward lower dissipation rate in the pycnocline, that we attribute to the lack of representation of the ITF and mesoscale circulation and a bias toward higher dissipation rate in the weak mixing region, suggesting an overestimation of the background dissipation rate in calm waters.

中文翻译：

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从印度尼西亚海域历史 CTD 数据集推断的湍流混合空间结构

摘要 印度尼西亚海域的湍流动能耗散率和垂直扩散率是从历史 CTD 测量结果中推断出来的，这是首次从印度尼西亚和国际航行中收集的数据。耗散率是使用改进的索普标度方法从 CTD 推断出来的，该方法已针对微观结构测量进行了验证。在近场站观察到耗散率升高~[10-6-10-7] m2 s-3，例如在产生内部潮汐和印度尼西亚通流（ITF）强烈的海峡、狭窄的通道和变浅的地形中，而较低的耗散率~[10−8–10−10] m2 s−3 在远场站和pycnocline 下方观察到。ITF西线主要混合热点位于拉巴尼海峡和德瓦康水域较浅的地形，即通过苏拉威西海、望加锡海峡和弗洛雷斯海连接北太平洋源头的通道；位于哈马黑拉海峡、利法马托拉海峡、布鲁海峡，为ITF东线航线，即通过哈马黑拉海、马鲁古海、塞拉姆海连接南太平洋源头的通道；在 ITF 出口通道，即龙目海峡、萨佩海峡和翁拜海峡。东线比西线耗散性更强，这与东线太平洋海域盐度峰值侵蚀较强是一致的。我们发现潮汐变化会影响耗散率和扩散率，正如 yoyo 剖面数据集所建议的那样。从 Nagai 和 Hibiya (2015) 的高分辨率 3D 流体动力学模型输出推断出的耗散率空间模式与混合热点位置的观测结果基本一致，表明 M2 内部潮汐是驱动的主要因素印度尼西亚海域的湍流动能耗散率。然而，该模型还显示出偏斜层中耗散率偏低，我们将其归因于缺乏 ITF 和中尺度环流的表示以及弱混合区域中耗散率偏高，这表明背景耗散率被高估在平静的水域。