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

这个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一定程度，它变得足够成熟，可以在冬季后期，甚至可能是冬季中期将温暖的水带到表面并融化现有的冰盖。具体研究将探讨在典型的南极条件下，海水密度对温度和盐度的非线性依赖（状态方程）如何增强垂直对流。当密度相似但温度和盐度差异很大的海水层相互作用时，会产生许多可能的非线性不稳定性，将现有势能转化为湍流能。在威德尔海，一个寒冷的表面混合层经常被一个薄而弱的斜斜与下面的温暖的、更咸的水分开，使得水柱特别容易受到与热压性（热膨胀系数的压力依赖性）相关的不稳定性的影响。该项目由纽约大学、地球与空间研究中心、华盛顿大学、海军研究生院和麦克菲研究公司合作完成。这项工作在解释威德尔冰海的存在方面具有很强的实际应用价值。威德尔冰海是威德尔海季节性海冰内的一片30万平方公里的开放水域，大约从1975年到1979年。尽管在莫德隆起海底山附近确实出现了更小、更不持久的开放水域，但从那以后，它就没有再出现过。实验部件将于2005年7月至9月在RVIB Nathaniel B. Palmer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.