Temperature, salinity profiles and associated data collected in the Southern Oceans in support of the Global Ocean Ecosystem Dynamics project, April - August 2001 (NODC Accession 0001097)

The overall goal of the U.S. Southern Ocean GLOBEC program is to elucidate circulation processes and their effect on sea ice formation and Antarctic krill (Euphausia superba) distribution and to examine the factors that govern Antarctic krill survivorship and availability to higher trophic levels, including penguins, seals, and whales. Consequently, a primary objective of this second U.S. SO GLOBEC broad-scale survey cruise (NBP01 04) is to provide a description of the water mass distribution and circulation on the west Antarctic Peninsula (WAP) continental shelf in the region of Marguerite Bay.
Historical hydrographic data for this region are limited, particularly during times other than austral summer. However, these data show that the water masses in the area consist of Antarctic Surface Water (AASW) in the upper 100 m to 120 m, a cold Winter Water layer at 80 m to 120 m, and a modified form of Upper Circumpolar Deep Water (UCDW) that covers the shelf below the permanent pycnocline at 150 m to 200 m. The UCDW, which is the source for the modified water on the WAP shelf, is found at the outer edge of the continental shelf at depths of 200 to 600 m. Thus, the first objective of the hydrography component is to fully describe the water mass distribution on the WAP continental shelf. This objective also includes showing how the water structure changes from the first regional survey, which was only two months ago.
Circulation in the study region, which has been inferred from the limited hydrographic observations, suggests a clockwise gyre on the continental shelf near Marguerite Bay, upwelling of UCDW at specific sites in the study region, and across shelf flow of UCDW into Marguerite Bay at depth. However, the details of the circulation and the spatial and temporal variability of the flow remain to be determined. Thus, the second objective of the hydrography component is to provide a description of the large scale circulation for the portion of the WAP continental shelf included in the study region. The resulting circulation distribution can then be compared with drifter, moored current, and shipboard ADCP measurements as well as circulation derived from theoretical models.

美国南大洋全球海洋生态系统动力学（GLOBEC）计划的总体目标为阐明环流过程及其对海冰形成、南极磷虾（*Euphausia superba*）分布的影响，同时探究调控南极磷虾生存能力以及其向企鹅、海豹、鲸等更高营养级类群的资源可获得性的相关因子。据此，本次美国南大洋GLOBEC第二次大范围调查航次（NBP01 04）的核心目标之一，是刻画玛格丽特湾海域南极半岛西部（WAP）大陆架的水团分布与环流特征。

该区域的历史水文数据较为匮乏，尤其是南半球夏季以外的时段。现有观测数据表明，该区域水团可分为三层：上层100~120米的南极表层水（AASW）、80~120米深度的寒冷冬季水层，以及150~200米处永久密度跃层之下覆盖大陆架的改性上层环极深水（UCDW）。作为南极半岛西部大陆架改性水团的源水，UCDW分布于大陆架外缘200~600米的深度区间。因此，水文调查组分的首要目标是完整刻画南极半岛西部大陆架的水团分布特征，该目标同时涵盖对比仅两个月前完成的首次区域调查，阐明该水域结构的变化情况。

基于有限的水文观测结果推断，研究区域的环流特征表现为：玛格丽特湾附近大陆架存在顺时针环流涡旋、研究区域特定点位存在UCDW上升流、UCDW以跨陆架深层流的形式汇入玛格丽特湾。但环流的精细结构以及流场的时空变异性仍有待明确。据此，水文调查组分的第二项目标是描述研究区域覆盖的南极半岛西部大陆架区段的大尺度环流特征。后续可将所得环流分布结果与漂流浮标、锚定海流计、船载声学多普勒流速剖面仪（ADCP）的实测数据，以及理论模型推导的环流结果进行比对验证。