Abstract This study uses ROMS (Regional Ocean Modeling System) with realistic forcing to analyse cross-shelf transport associated with the presence of mesoscale anticyclones as they interact with the western shelf of the Gulf of Mexico. Daily outputs from this validated 15-year numerical simulation were used to calculate the depth and time averaged cross-shelf volume transport through the 200 m isobath, used as a proxy for the shelf break. Composites for cases in which mesoscale anticyclones (MAs) are close or far away from the shelf break were performed to show that cross-shelf exchange has remarkable differences when they interact with the shelf. These differences consist of: a) enhanced off-shelf transport on its northern rim (at ~ 25.5oN), b) a flow with multiple inversions associated with the main body of the MA where both on and off-shelf transports are considerably increased, and c) enhanced on-shelf transport at its southern edge, linked to the interaction of the MA with the persistent mesoscale cyclonic circulation in the Bay of Campeche. The multiple transport inversions associated with the main body of the MA is clearly linked with spatial patterns of baroclinic and barotropic instabilities that develop at the rings edge. The time-evolution of a representative event in which an MA interacts with the shelf is analysed to verify the influence on cross-shelf transport observed in the composites. Results show that enhanced cross-shelf transport is driven by the proximity, shape, and angle of orientation of the anticyclone with respect to the shelf. The Eulerian analysis of the event coincides with the composite results described above with enhanced cross-shelf exchange when the MA is rounder and closer to the shelf. A Lagrangian experiment is carried out to quantify the exchange and fate of particles during this “typical eddy event”, seeding drifters within the shelf, inside the MA and in the open waters outside the eddy. Results show a substantial increase in exchange rate and distance traveled by particles (they travel 200 km farther) when the MA is closer to the shelf.

中文翻译：

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中尺度涡旋对墨西哥湾西部跨陆架交换的影响

摘要 本研究使用具有真实强迫的 ROMS（区域海洋建模系统）来分析与中尺度反气旋与墨西哥湾西部大陆架相互作用时存在的跨大陆架运输。这个经过验证的 15 年数值模拟的每日输出用于计算通过 200 m 等深线的深度和时间平均跨货架体积运输，用作货架断裂的代理。对中尺度反气旋 (MA) 靠近或远离架子断裂的情况进行了复合，以表明当它们与架子相互作用时，跨架子交换具有显着差异。这些差异包括：a) 其北缘（约 25.5oN）的货架外运输增强，b) 与 MA 主体相关的多次反转的流动，其中架上和架外运输都显着增加，并且 c) 其南部边缘的架上运输增强，这与 MA 与持久性的相互作用有关坎佩切湾中尺度气旋环流。与 MA 主体相关的多次输运反转与在环边缘发展的斜压和正压不稳定性的空间模式明显相关。分析了 MA 与货架相互作用的代表性事件的时间演变，以验证对复合材料中观察到的跨货架运输的影响。结果表明，增强的跨架运输是由反气旋相对于架的接近度、形状和定向角度驱动的。事件的欧拉分析与上述复合结果一致，当 MA 更圆且更靠近货架时，跨货架交换增强。进行了拉格朗日实验来量化这种“典型涡流事件”中粒子的交换和命运，在大陆架内、MA 内和涡流外的开放水域中播种漂流物。结果表明，当 MA 离架子越近时，交换率和粒子行进的距离（它们行进 200 公里远）显着增加。MA 内和涡流外的开阔水域。结果表明，当 MA 离架子越近时，交换率和粒子行进的距离（它们行进 200 公里远）会显着增加。MA 内和涡流外的开阔水域。结果表明，当 MA 离架子越近时，交换率和粒子行进的距离（它们行进 200 公里远）会显着增加。