Bio-Physical Variability in Regions of the Southern Ocean with Contrasting Climatic Response - The Eastern Amundsen & Ross Seas

极地项目办公室、南极科学部、大气与海洋项目颁发了这一奖项，旨在通过“奥登”号破冰船的研究巡航，研究阿蒙森海和罗斯海不寻常的生物地球化学以及不断变化的海洋和冰况。生物地球化学的焦点是由最近观察到的南大洋表层水体中营养磷相对于硝酸盐和碳的高吸收量引起的，并伴随着底层水体相对快速的再生。控制南大洋中深水异常低氮磷比的机制尚未确定，但模式和观测都表明，在该地区设定的氮磷比并输送到低纬度地区，可以模拟低纬度环流中的硝化作用。通过这种方式，南大洋的过程可以影响全球海洋养分循环。此外，海洋沉积物证据表明，南大洋的生产力在时间上发生了显著变化。为了更好地了解全球营养循环及其变化，有必要更好地记录南大洋的情况。阿蒙森和罗斯海地区也令人感兴趣，因为它们与以威德尔海为中心的大西洋地区表现出非相位的气候异常。海冰覆盖和风的异常跷跷板模式，即南极偶极子现象，似乎与更大尺度的大气压力模式（如厄尔Niño南方涛动）有关。海洋在这些联系中的作用仍有待澄清。此外，阿蒙森海和罗斯海分别具有狭窄和宽阔的冰架，它们提供的温暖的环极深水可以融化冰架。建议开展包括生物地球化学测量在内的基础水文测量，以研究1)环极地深水侵入陆架，2)淡水储量的变化，3)南大洋水域异常的氮磷比及其对全球海洋的影响。第三条穿越南极偶极子太平洋中心的XBT/XCTD/CT样带将补充一个单独资助的系泊项目。计划中的工作延长了以前类似的水文调查的时间序列。水文数据的获取和解释直接与参与的瑞典调查人员合作，并将为这次奥登巡航上进行的其他科学项目提供必要的背景。更广泛的影响：拟议的跨大陆架航道线是WOCE/CLIVAR计划中经过国际审查的优先航道线的延伸。数据将通过国家海洋数据中心提供。一名本科生实习生将从事气候数据处理工作。该研究项目将作为Lamont Doherty地球观测站年度开放日的一部分，每年有超过1000人参观。2个PI？S是女性，因此这个项目将增加一个在物理海洋学方面代表性特别不足的群体的参与。

The Office of Polar Programs, Antarctic Science Division, Atmosphere & Oceans Program has made this award to address a combination of unusual biogeochemistry and changing ocean and ice conditions in the Amundsen and Ross Seas via a research cruise on the Icebreaker Oden. The biogeochemical focus is motivated by recent observations of high uptake of the nutrient phosphorus relative to nitrate and carbon in surface waters of the Southern Ocean accompanied by relatively rapid regeneration in underlying waters. Mechanisms controlling unusually low N:P ratios in intermediate and deep waters of the Southern Ocean are yet to be determined but both models and observations suggest that ratios set in this region and transported to lower latitudes, could simulate nitrification in the low latitude gyres. In this way processes in the Southern Ocean could influence global marine nutrient cycling. Moreover, marine sediment evidence suggests that Southern Ocean productivity has varied significantly in time. To better understand global nutrient cycling and its variability, it is important to better document the situation in the Southern Ocean. The Amundsen and Ross Sea regions are additionally of interest because they exhibit out of phase climate anomalies with the Atlantic sector centered on the Weddell Sea. The seesaw pattern of anomalies in sea ice cover and wind patterns, known as the Antarctic dipole, seems to be governed by connections with larger scale atmospheric pressure patterns such as the El Niño Southern Oscillation. The role of the ocean in these connections remains to be clarified. Additionally, the Amundsen and Ross seas with narrow and broad shelves respectively present contrasting situations for the delivery of warm circumpolar deep water that can melt ice shelves. It is proposed to carry out basic hydrographic surveys including biogeochemical measurements along two cross-shelf transects to examine 1) Circumpolar Deep Water intrusions on the shelf, 2) changes in freshwater inventories, 3) the unusual ratios of nitrogen to phosphorus of Southern Ocean waters and their influence on the global oceans. A third XBT/XCTD/CT transect through the Pacific center of the Antarctic dipole is proposed that would complement a separately funded mooring based project. The planned work extends the times series of similar, previous hydrographic surveys. The acquisition and interpretation of hydrographic data is directly collaborative with participating Swedish investigators and will provide necessary context for other science projects that will be carried out on this Oden cruise. Broader impacts: The proposed cross-shelf hydrographic lines are extensions of internationally vetted priority hydrographic lines for the WOCE/CLIVAR program. Data will be made available through the National Ocean Data Center. An undergraduate intern will be engaged in the climate data manipulation. The research program will be featured as part of the Lamont Doherty Earth Observatory Annual Open House which is visited by more than a thousand people. Two of the PI?s are female and so this project will increase participation of a group particularly underrepresented in physical oceanography.