海湾内传输过程时间尺度的计算方法

Computational methods for transport time scales in a bay

为了探明海湾中水体交换、污染物扩散等过程中的物质传输特征,提出相应传输时间尺度的计算方法并进行数值模拟分析。基于水动力模型COHERENS,分别采用基于粒子跟踪法的Lagrange方法和基于对流-扩散方程的Eul-er方法对东京湾的滞留时间和游弋时间进行计算。结果显示:传输时间尺度在东京湾中的分布特征,表明水体自外洋进入海湾后的传输过程及湾内外水体的交换速率都在空间上存在差异。本方法既可用于估计水体系统宏观的传输时间尺度,亦能得到其空间分布。

Transport time scales in bays were analyzed numerically to study the water mass transportation in bays, which dominates the water exchange and contaminant spread. The residence time and age in Tokyo Bay were studied based on a three-dimensional coupled hydrodynamic-ecological model for regional shelf seas （COHERENS）. The Lagrangian method using particle tracing algorithm and the Eulerian method using the advection-diffusion equations both reasonably predict the distribution of transport time scales in Tokyo Bay, which indicate that the transport of the incoming water from the open sea and the water exchange rate have spatial differences. The present method gives not only the transport time scale of the bay as a whole but also the detailed spatial distribution within the bay.