Collaborative Research: Modeling Thermobaric Effects in Antarctic Deep Ocean Convection

[125528 . stanton]这个合作项目是对海洋热压不稳定及其对南大洋深层对流影响的模拟研究。温压不稳定指的是海水的可压缩性是压力的非线性函数，因此，较冷较新鲜的一层覆盖在较热较咸的一层上，可能在静态上是稳定的，但如果受到干扰，就会变得不稳定。人们早就知道这在理论上是可能的，但直到最近，人们才认为这是一种可能在南大洋发生的效应，特别是作为威德尔海（威德尔海冰盖内大片开阔水域）间歇性出现的潜在解释。热压性对深海对流影响的评估将基于一个数值大涡模拟（LES）模式，该模式能够直接模拟对流羽流和大尺度海洋流动特征，这些特征将由强烈的热压翻转引起。根据先前在威德尔海进行的海洋考察中观测到的条件初始化和强制的LES模型的初步结果，这项拟议的工作将结合一系列精心构建的模型运行和观测结果，以确定关键的倾覆过程。

0125528Stanton This collaborative project is a modeling study of thermobaric instability in the ocean, and its effect on deep convection in the Southern Ocean. Thermobaric instability refers to the fact that the compressibility of sea water is a non-linear function of pressure, so that a colder and fresher layer overlying a warmer and a saltier layer may be statically stable, but become unstable if it is disturbed. That this is theoretically possible has been known for a long time, but only recently has it been considered as an effect that could actually occur in the Southern Ocean, specifically as the potential explanation of the episodic occurrence of polynyas (sizable areas of open water within the sea-ice pack) in the Weddell Sea. This evaluation of the impact of thermobaricity on deep ocean convection will be based on a numerical Large Eddy Simulation (LES) model capable of simulating directly the convection plumes and large scale oceanic flow features that would be expected with intense thermobaric overturn. Based on preliminary results of an LES model initialized and forced by conditions observed during previous oceanographic cruises to the Weddell Sea, this proposed work will combine a carefully structured series of model runs with observations to identify critical overturning processes.