Collaborative Research: Marine Climate and Relative Sea Level Across Central Beringia

布里格姆-格雷特白令海峡将白令群岛的广大地区隔开。 北太平洋富营养沃茨沿沿着东白令海大陆坡向北流动，越过大陆架进入楚科奇海，维持着较高的表层水。 太平洋沃茨也贡献了北冰洋淡水预算的30%（约占河流贡献的一半），这有助于维持北极盐跃层，北极海冰，并调节北大西洋地区的气候。 在最后一次盛冰期（LGM），海平面下降了125米，白令海更大，太平洋和北冰洋分开了近1000公里。 由于海洋距离很远，白令的气候比较均匀。由于缺乏周围海洋的数据，海洋在控制白令气候方面的确切作用尚不清楚。 相对海平面的历史所知甚少，但由于构造和可能的冰川-海平面升降效应，相对海平面的历史可能与海平面升降不同。 海洋表面条件，如冰的范围，温度和盐度可能会影响气候通过热效应，热交换和湿度，但在白令海和楚科奇海几乎没有这些属性的高分辨率代理数据。 为了将白令海的海洋和陆地领域联系起来，主要调查人员将参加白令海和楚科奇海的重力、活塞和振动监测实地项目，以开发以下高分辨率记录：1）白令海的中层海洋通风; 2）白令海和楚科奇海的海洋表面温度、盐度、海冰范围和冰山排放历史;（3）末次冰期以来白令海峡地区的相对海平面。 这些目标与1999年10月国家科学基金会主办的关于“评估过去20 000年北极水深变化和淡水输入对大陆架和海洋环流的影响”的讲习班的主题密切相关。"

AbstractOPP-99-12122KeigwinOPP-00-02643Brigham-GretteThe broad region of Beringia is separated by the Bering Strait. North Pacific waters rich in nutrients flow northward along the eastern Bering Sea continental slope, across the shelf and into the Chukchi Sea, sustaining high surface water. The Pacific waters also contribute about 30 percent of the Arctic Ocean's fresh water budget (about half of the river's contribution) which helps maintain the Arctic halocline, Arctic sea ice, and regulates climate in the North Atlantic region. During the last glacial maximum (LGM), sea level was lowered by 125 meters, Beringia was much larger and the Pacific and Arctic Oceans were separated by nearly 1000 kilometers. Beringian climate was more uniform because the sea was so distant.The exact role of the ocean in controlling Beringian climate is unknown because of the lack of data on the surrounding seas. The history of relative sea level is poorly known, but is likely to have differed from eustatic sea level because of tectonic and possible glacio-eustatic effects. Sea surface conditions such as ice extent, temperature, and salinity are likely to influence the climate through albedo effects, heat exchange, and humidity, but there are almost no high-resolution proxy data for these properties in the Bering and Chukchi Seas. To link the marine and terrestrial realms in Beringia, the Principal Investigators will participate in a field program of gravity, piston and vibracoring in the Bering and Chukchi Seas to develop high resolution records of 1) intermediate ocean ventilation in the Bering Sea; 2) surface ocean temperature, salinity, sea ice extent, and history of iceberg discharge in both the Bering and Chukchi Seas; and 3) relative sea level in the Bering Strait region since the LGM. These objectives are closely aligned with the theme of the October 1999 NSF-sponsored workshop on "Assessing Impacts of Arctic Bathymetry Changes and Fresh Water Inputs on Shelf and Ocean Circulation for the Past 20,000 Years."