A climatology of the marine atmospheric boundary layer (MABL) and the lower free troposphere over the Southern Ocean (SO) is constructed using 2,186 high‐resolution atmospheric soundings from four recent campaigns conducted in the period of 2016–2018. Relationships between the synoptic meteorology and MABL thermodynamic structure are examined using a k‐means cluster analysis, complemented by front and cyclone composite analyses. Seven distinct clusters are identified, five of which are consistent with an established climatology over the SO storm track. Two new clusters (C1 and C2) are introduced over the high‐latitude SO. C1 is commonly located poleward of the ocean polar front near mesocyclones, while C2 is located along the Antarctic coastline. A multilayer cloud structure is frequently present in clusters in the vicinity of fronts and cyclones, while a single‐layer coverage is more common in a suppressed environment, particularly at lower latitudes. A cloud‐free, multilevel inversion is frequently observed in cluster C2, possibly linked to the descending, dry, katabatic winds off the Antarctic coast. A strong, primary inversion is typically present in clusters at lower latitudes with high mean sea level pressure. Across the SO storm track and higher latitudes (cluster C1), a multilevel inversion structure is also commonly observed. A preliminary analysis of two case studies suggests that upper level advection and detrainment of convection associated with mesocyclones are potential drivers of the multilayer cloud coverage over the high‐latitude SO rather than the decoupling mechanisms common in the subtropics.

中文翻译：

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2016-2018年四次野外运动对南大洋海洋边界层的气候学

使用2016-2018年期间进行的四次近期活动中的2,186个高分辨率大气探测，构造了海洋大气边界层（MABL）和南大洋对流层低层（SO）的气候。使用k检验天气气象学和MABL热力学结构之间的关系。均值聚类分析，并进行前风和旋风综合分析。确定了七个不同的星团，其中五个与SO风暴轨道上已建立的气候相一致。在高纬度SO上引入了两个新的集群（C1和C2）。C1通常位于中气旋附近的海洋极地极的极点，而C2位于南极海岸线。多层云结构经常出现在锋面和气旋附近的簇中，而在受抑制的环境中，尤其是在低纬度地区，单层覆盖更为普遍。在C2集群中经常观察到无云的多级反演，这可能与南极海岸外的干燥，干燥的方差风有关。一个强壮的，一次反转通常出现在平均海平面压力较高的较低纬度的集群中。在SO风暴路径和更高纬度（集群C1）上，也通常会观察到多级反演结构。对两个案例研究的初步分析表明，与中气旋相关的高层对流和对流减弱是高纬度SO上多层云覆盖的潜在驱动因素，而不是亚热带常见的解耦机制。