用OPA9全球海洋环流模式模拟不同类型El Nino事件

Simulation of Different Categories of El Nino Events by Global Oceanic General Circulation Model OPA9

摘要:

根据El Nino事件中正的海表面温度异常(sea surface temperature anomaly,简称SSTA)首先出现的区域及其传播特征,将El Nino事件分成3种类型,即东部型、西部型和驻波型。为了研究不同类型El Nino事件物理机制的差异,首先利用高分辨率全球海洋环流模式OPA9,对这3种不同类型的El Nino事件进行模拟。在逐月海表面风应力和热通量的驱动下,模式模拟出了1950-2005年间全球海温演变。模拟结果表明,模式可以很好地模拟出海洋的气候态,并且对El Nino事件期间的正SSTA首先出现的区域以及对正SSTA的传播特征都做出了很好的模拟,成功地模拟了不同El Nino事件的发展类型。

关键词:OPA9;海洋环流模式;El Nino的不同类型;数值模拟

Abstract:

In this paper, El Nino events are classified into three categories:eastern pattern, western pattern and stationary wave pattern according to the region El Nino initially occurs and the propagation features of the positive sea surface temperature anomaly(hereafter referred as SSTA) of El Nino. In order to study the differences of the physical mechanisms of El Nino events, our prime task is to simulate the development process of these various types of El Nino. OPA9, a global oceanic general circulation model with high resolution, is applied to simulate the three categories of El Nino events. Global sea surface temperature changes from 1950-2005 are simulated in this model forced by monthly sea surface wind stress and heat flux. Analysis of the simulation results for the 56 years shows that, the model simulates oceans' climatology very well;in addition, the region El Nino initially occurs and the propagation features of SSTA of El Nino are properly simulated by the model. That is to say, the model simulates the warm events of the three categories successfully.

Key words:OPA9;oceanic general circulation model;different categories of El Nino;numerical simulation