Collaborative Research: The Maud Rise Nonlinear Equation of State Study (MaudNESS)

合作研究：莫德上升非线性状态方程研究 (MaudNESS)

• 批准号: 0337301
• 负责人: Laurence Padman
• 金额: $ 36.83万
• 依托单位: Earth and Space Research
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0337301&HistoricalAwards=false
• 关键词: Collaborative; Research; Maud; Rise; Nonlinear

This project is an investigation into one mechanism by which deep ocean convection can evolve from stable initial conditions, to the extent that it becomes well enough established to bring warm water to the surface and melt an existing ice cover in late, or possibly even mid-winter. The specific study will investigate how the non-linear dependence of seawater density on temperature and salinity (the equation of state) can enhance vertical convection under typical antarctic conditions. When layers of seawater with similar densities but strong contrasts in temperature and salinity interact, there are a number of possible non-linear instabilities that can convert existing potential energy to turbulent energy. In the Weddell Sea, a cold surface mixed layer is often separated from the underlying warm, more saline water by a thin, weak pycnocline, making the water column particularly susceptible to an instability associated with thermobaricity (the pressure dependence of the thermal expansion coefficient). The project is a collaboration between New York University, Earth and Space Research, the University of Washington, the Naval Postgraduate School, and McPhee Research Company.The work has strong practical applications in contributing to the explanation for the existence of the Weddell Polynya, a 300,000 square kilometer area of open water within the seasonal sea ice of the Weddell Sea, from approximately 1975 to 1979. It has not recurred since, although indications of much smaller and less persistent areas of open water do occur in the vicinity of the Maud Rise seamount. The experimental component will be carried out on board the RVIB Nathaniel B. Palmer between July and September, 2005.

该项目是对一种机制的调查，通过这种机制，深海对流可以从稳定的初始条件发展到足够成熟的程度，将温暖的海水带到表面，并在冬季后期甚至可能是冬季中期融化现有的冰盖。 具体的研究将调查海水密度对温度和盐度的非线性依赖性（状态方程）如何在典型的南极条件下增强垂直对流。当具有相似密度但温度和盐度强烈对比的海水层相互作用时，存在许多可能的非线性不稳定性，这些不稳定性可以将现有的势能转化为湍流能量。 在威德尔海，一个寒冷的表面混合层往往被一层薄而弱的密度跃层从下面温暖的盐水中分离出来，使得水柱特别容易受到与温压性（热膨胀系数的压力依赖性）相关的不稳定性的影响。 该项目是纽约大学、地球与空间研究所、华盛顿大学、海军研究生院和麦克菲研究公司之间的合作项目。这项工作在解释威德尔波林尼亚的存在方面具有很强的实际应用价值。威德尔波林尼亚是威德尔海季节性海冰内一个30万平方公里的开放水域，从1975年到1979年。 自那以后，这种现象没有再出现，尽管有迹象表明，在莫德海隆附近确实出现了小得多、持续性较低的开阔水域。 实验部分将在RVI B Nathaniel B上进行。在2005年7月到9月间。