High Resolution Underway Observations in Drake Passage: Ocean Physics

南极绕极流是世界上最强的洋流，其流速是地球上所有河流总和的100多倍。该项目继续对ACC的海洋性质和变异性进行长期研究，方法是使用USAP补给舰RV/AS LMGill，重复横跨从蓬塔阿雷纳斯到帕尔默站的德雷克航道。该项目将提供关于南大洋锋面、地表水质量特性、热量和盐度预算的长期趋势和变化的信息。这项研究将有助于理解ACC在气候相关时间尺度上对大气强迫的响应，以及它在驱动南大洋经向翻转环流中的作用。该项目将在德雷克海峡继续进行高分辨率、近重复的XBT/XCTD/ADCP样带采样，以研究南极绕极流(ACC)中海洋温度、盐度、洋流和后向散射的变化模式。这些数据将捕捉从季节到年际的时间尺度上的可变性，以及从当前核心到旋涡的空间尺度上的可变性。利用现有近20年的数据，主要科学目标是分析德雷克海峡的时间序列，(1)描述海洋能量的季节和长期分布，并将其与风、浮力和地形强迫和汇联系起来；(2)描述ACC锋面、水团和上升流的季节和长期变化，并将其与生物地球化学变化联系起来。持续的数据收集、质量控制和向更广泛的海洋学界传播德雷克航道数据集是该项目的关键组成部分。

The Antarctic Circumpolar Current (ACC) is the strongest ocean current in the world, with a flow rate more than 100 times greater than all the rivers on Earth combined. This project continues a long-term study of ocean properties and variability in the ACC by repeat transects across the Drake Passage from Punta Arenas to Palmer Station using the USAP supply ship RV/AS LMGould. This project will provide information about long term trends and variability in Southern Ocean fronts, surface water mass properties, heat, and salinity budgets. This study will contribute to understanding the response of the ACC to atmospheric forcing on climate relevant time scales, and its role in driving the meridional overturning circulation of the Southern Ocean. These data represent the only year-round shipboard measurements in the Southern Ocean.This project will continue high-resolution, near-repeat XBT/XCTD/ADCP transect sampling in Drake Passage in order to study modes of variability in ocean temperature, salinity, currents and backscatter in the Antarctic Circumpolar Current (ACC). The data will capture variability on time scales from seasonal to interannual and on spatial scales from current cores to eddies. With almost two decades of data now available, the primary science objectives are to analyze the Drake Passage time series and (1) describe and relate the seasonal and long-term ocean energy distribution to wind, buoyancy and topographic forcing and sinks, and (2) describe and relate seasonal and long-term changes in the ACC fronts, water masses and upwelling to biogeochemical variability. The continued data collection, quality control and dissemination of the Drake Passage data sets to the broader oceanographic community are critical components of the project.