外强迫引起的夏季大气环流异常及其机制探讨

On the Mechanism of Summertime Atmospheric Anomalies Induced by External Forcing

本文主要探讨了夏季模式大气对热带海温和高纬极冰异常的外强迫响应机制,结果表明,在大气环流模式长时间积分以后,不同的外强迫源均可在全球大气的一些关键性区域激发产生相同的环流异常型,即夏季大气主要异常型对外强迫源地理位置不敏感,很大程度上依赖于大气内部动力学过程.根据以上特点本文提出外强迫引起大气异常存在两类机制,其中外强迫和大气内部动力学过程相互作用机制是产生大气异常的重要动力学途径.

By using a perpetual July, nine level general circulation spectral model with rhomboidal truncation at wavenumber 15 incorporated a comprehensive set of physical processes, a series of numerical experiments have been conducted to determine the mechanism of atmospheric anomalies induced by external forcing such as anomalies of the sea surface temperature and Arctic sea ice cover during the Northern Hemisphere summer. It is shown that the leading anomaly patterns observed in real atmosphere can be produced by external forcing. However, the patterns are insensitive to the positions of external forcing, but depend strongly on the internal dynamics of the atmosphere especially on the structure of the basic flow. There exist two kinds of mechanisms to interpret the role of external forcing on the atmospheric anomalies, of which the interaction between external forcing and internal atmospheric dynamical processes is a very important aspect.