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

这个项目是对深海对流的一种机制的研究，通过这种机制，深海对流可以从稳定的初始条件演变到足以将温暖的水带到地表并在晚冬甚至仲冬融化现有冰盖的程度。这项具体研究将调查海水密度对温度和盐度的非线性依赖(状态方程)如何在典型的南极条件下增强垂直对流。当密度相似但温度和盐度反差较大的海水层相互作用时，可能存在一些非线性不稳定性，可以将现有势能转化为湍流能量。在韦德尔海，寒冷的表面混合层通常与下层温暖的、更咸的水被一层薄而弱的跃层隔开，这使得水柱特别容易受到与热压性(热膨胀系数的压力相关性)相关的不稳定的影响。该项目是纽约大学、地球和空间研究中心、华盛顿大学、海军研究生院和麦克菲研究公司的合作项目。该项目在解释韦德尔波利尼亚的存在方面具有很强的实际应用价值。韦德尔波利尼亚是大约1975至1979年间韦德尔海季节性海冰内30万平方公里的开放水域。自那以后，这种情况再也没有发生过，尽管有迹象表明，在莫德海山附近确实出现了面积更小、持续时间更短的开阔水域。实验部分将于2005年7月至9月在RVIB纳撒尼尔·B·帕尔默号上进行。

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.