Modelling Jets and Vortices in the Ocean

本研究计划的目标是发展和改进海洋系统的理想模型，并确定生物地球化学特性如何在一些观测受限的射流和涡旋系统中传输。除潮汐外，喷流和漩涡是海洋中最具能量的特征，因此在海洋物理和生物特性的分布中起着至关重要的作用。使用最新开发的高性能计算软件，模型方程将被数值求解，以解决大范围的长度和时间尺度。这将有助于我们理解控制中尺度或中尺度附近能量转移的物理机制。更具体地说，这项研究计划将回答一系列基本问题，包括：1)哪些特性对决定射流和旋涡的稳定性至关重要？2)当不稳定性发展时，它们如何在非线性状态下演化，然后饱和以达到非线性平衡？3)由于不稳定过程，能量是如何在不同长度和时间尺度之间级联的？4)这些非线性过程对生态系统的物理和生物地球化学性质的传递有什么影响，从而对生态系统的生命周期有什么影响？

The objective of this research program is to develop and improve idealized models of oceanic systems and determine how biogeochemical properties are transported in a number of observationally-constrained systems of jets and vortices.  Excluding tides, jets and vortices are the most energetic features in the ocean and therefore play a crucial role in the distribution of physical and biological oceanic properties. Using recently-developed high performance computing software, the model equations will be solved numerically to resolve a wide range of length and time scales.  This will help us to understand the physical mechanisms that govern the energy transfers at or near the mesoscale. More specifically, this research program will answer a set of fundamental questions including: 1) Which properties are crucial in determining the stability of jets and vortices?  2) When instabilities develop, how do they evolve in the nonlinear regime and then saturate to achieve nonlinear equilibration?  3) As a result of the instability processes, how is energy cascaded between the various length and time scales?  4) What effect do these nonlinear processes have on the transport of physical and biogeochemical properties and therefore on the lifecycle of ecosystems? A variety of oceanic models are used to study large-scale oceanic flows.  The most general model that can be used to study virtually all large-scale oceanic phenomenon is the nonhydrostatic primitive equation (NH) model.  Two simplified limits of this model are the multi-layer Shallow Water (SW) and Quasi-Geostrophic (QG) models. My research group will use the QG, SW and NH models to idealize currents and determine their stability characteristics and induced transport. We will accomplish this in collaboration with several international observational oceanographers.  Four current systems of interest are the Bransifield Current, the Gulf of Oman Current, the Antarctic Slope Front  and the Beaufort Gyre. Our study of three-dimensional vortices will begin with idealized vortex structures but also observations of meddies using very fine scale data from seismic reflection techniques. A complimentary aspect of this research program is to investigate some of these physical systems coupled to either simple Nutrient-Phytoplankton-Zooplankton models or ones that contain size-structure.  This will enable us to determine how biological organisms are transported and emitted from currents and vortices and subsequently transported over great distances.