The ocean surface mixed layer represents a critical interface linking the ocean and atmosphere. The physical processes determining the surface mixed layer properties and mediate atmosphere–ocean exchange. Submesoscale processes play a key role in cross-scale oceanic energy transformation and the determination of surface mixed-layer properties, including the enhancement of vertical nutrient transport, leading to increased primary productivity. Herein, we presented observations of the spiral chlorophyll-a filament and its influence on turbulence within an anticyclonic eddy in the western South China Sea during August 2021. The filament had a negative Ertel potential vorticity associated with strong upwelled/downward currents (approximately 20–40 m/day). Across-filament sections of the in-situ profiles showed turbulent dissipation rates enhanced in the filament. We suggested this enhancement values can be attributed to submesoscale processes, which accounted for 25 % of the total parameterized turbulent dissipation rates. The present parametrized submesoscale turbulent scheme overestimated the in-situ values. The filament transferred kinetic energy upward to anticyclonic eddy via barotropic instability and gained energy from the anticyclonic eddy via baroclinic instability. After kinetic energy budget diagnostic, we suggested besides symmetric instability, centrifugal instability and mixed layer baroclinic instability should also be included in the turbulence scheme to overcome the overestimation. The observed dual energy transfers between the anticyclonic eddy and filament, and the observed high turbulent energy dissipation within the filament, emphasized the need for these processes to be accurately parameterized regional and climate models.

海洋表面混合层是连接海洋和大气的关键界面。物理过程决定表面混合层特性并调节大气-海洋交换。亚尺度过程在跨尺度海洋能量转化和表面混合层特性的确定中发挥着关键作用，包括 增强垂直养分输送，从而提高初级生产力。在此，我们提出了2021 年 8 月期间对南海西部 的螺旋叶绿素-a 细丝及其对反气旋涡旋内湍流的影响的观测 。该细丝具有与强上升/下降流相关的负 Ertel 位涡（大约 20- 40 m/天）。原位剖面的跨灯丝截面显示 灯丝中的湍流耗散率增强。我们认为这种增强值可归因于 亚介尺度过程，该过程占总参数化湍流耗散率的 25%。目前的参数化亚中尺度湍流方案高估了原位值。细丝通过正压不稳定性将动能向上传递给反气旋涡流，并通过斜压不稳定性从反气旋涡流获得能量。经过动能收支诊断后，我们建议除了对称不稳定之外，还应将离心不稳定和混合层斜压不稳定纳入湍流方案中，以克服高估。观察到的 反气旋涡流和细丝之间的双重能量转移，以及观察到的细丝内的高湍流能量耗散，强调了这些过程需要精确参数化的区域和气候模型。