Workshop on Thermobaric Instability in High Latitude Oceans

这笔款项将用于资助将于2000年10月在海军研究生院举办的海洋热压不稳定问题讲习班。温压不稳定性是指海水的可压缩性是压力的非线性函数，因此覆盖在较暖和较咸的层上的较冷和较新鲜的层可能是静态稳定的，但如果受到扰动，则会变得不稳定。这种效应在理论上是可能的，这在很长一段时间内就已为人所知，但直到最近才被认为是一种实际上可能发生在南大洋的效应，特别是作为对威德尔海周期性发生的多尼娅现象的潜在解释。研讨会的目的是聚集一群一方面具有海水热力学专业知识，另一方面在研究威德尔海的结构和特征方面有经验的海洋学家，探索热压不稳定性与南极上层海洋动力学的相关性，并与解释威德尔海观测到的冰和海洋现象的相互竞争的理论一起检验它。特别是1997年的南极通量研究，在纳入一个简单的上层海洋/冰模式时，表明到南半球冬季结束时，东部威德尔海的大部分地区容易受到温压不稳定的影响。因此，温压效应可能在威德尔海和南大洋其他区域的水柱总体稳定中发挥重要作用，可能进入南极绕极波的多年时间尺度，并可能在甚至更长的气候时间尺度上影响高纬度海洋的倾覆和通风。

This award will provide funds for the support of a workshop on thermobaric instability in the ocean, to be held at the Naval Postgraduate School in October 2000. 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 saltier layer may be statically stable, but become unstable if it is disturbed. That this effect 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 in the Weddell Sea.The objective of the workshop is to bring together a group of oceanographers with expertise in the thermodynamics of sea water on the one hand and experience in studying the structure and characteristics of the Weddell Sea on the other hand, to explore the relevance of thermobaric instability to antarctic upper ocean dynamics, and to test it along with competing theories in explaining the observed ice and ocean phenomena of the Weddell Sea.Observations from recent oceanographic cruises, particularly those of the Antarctic Flux Study of 1997, when integrated into a simple upper ocean/ice model, have indicated that much of the eastern Weddell Sea is susceptible to thermobaric instability by the end of the austral winter. It follows that thermobaric effects may play an important role in the overall water column stability in the Weddell Sea and other regions of the Southern Ocean, may feed into the multi-year time scale of the Antarctic Circumpolar Wave, and may affect the overturning and ventilation of the high latitude ocean at even longer climatic time scales.A formal workshop on this specific aspect of antarctic oceanography has not been convened before.