基于极地海冰中以盐度为预报量的数学模型研究

A Mathematical Model Based on Salinity as a Forecast Quantity in Polar Sea Ice

摘要: 海冰热力学是构造海冰热力学模式的物理基础，在海冰模拟和预报、海冰与气候系统相互作用中占有重要地位。长期以来，对极地海冰快速变化的认识更多地体现在宏观层面，冰内微观结构演变机制不健全，微观结构一般指海冰内部除冰晶体之外尺寸在mm量级的卤水、气泡等构造。卤水排泄过程较早得到人们关注，因为它控制着海冰盐度、冰面融池演变以及冰内生物等重要过程；可分为生长期排盐、温度梯度导致的盐分扩散、冰内相变导致的卤水排泄、重力排泄和融化期冲洗过程等五大类型，其中后两者对海冰盐度分布的影响最为显著。本文在Cox和Weeks提出的以盐度为预报量的参数化方案的基础上，模拟第一年南极浮冰的典型热力学状态。针对冰生长期的重力排泄、冰融化期的冲洗过程进行改进和研究。通过假设在理想化状态下，使用一维模型研究了通过假设后在理想状态下卤水动力学之间的相互作用，以合理复杂的海冰模型来重现盐度的时间演化，期望从这种类型的模型中得到多大程度的准确性。该模型所描述的传热、卤水体积和海水淡化之间的物理过程和相互作用，新模型可以帮助我们推断表面融水受初级生产影响的卤水动力学。

Abstract: Sea ice thermodynamics is the physical basis for constructing sea ice thermodynamic models, and plays an important role in sea ice simulation and forecasting, and sea ice interaction with the cli-mate system. For a long time, the understanding of rapid changes in polar sea ice has been more at the macroscopic level, and the mechanism of microstructure evolution within the ice is not sound. Microstructure generally refers to the structure of brine and air bubbles inside the sea ice with di-mensions in the order of mm except for ice crystals. The brine drainage process has received early attention because it controls important processes such as sea ice salinity, ice melt pond evolution, and intra-ice biology; it can be divided into five major types, such as brine drainage during the growth period, salt diffusion due to temperature gradient, brine drainage due to phase change within the ice, gravity drainage, and flushing process during the melting period, among which the latter two have the most significant effects on sea ice salinity distribution. In this paper, we simulate the typical thermodynamic state of Antarctic floating ice in the first year based on the parameteri-zation scheme proposed by Cox and Weeks with salinity as the forecast quantity. The gravitational discharge during the ice growth period and the flushing process during the ice melting period are improved and studied. The interactions between brine dynamics under idealized conditions through assumptions are studied using a one-dimensional model to reproduce the time evolution of salinity with a reasonably complex sea ice model, by assuming how much accuracy is expected from this type of model. The physical processes and interactions between heat transfer, brine volume and desalination are described by the model, the new model can help us to infer the brine dynamics of surface meltwater affected by primary production.