Discontinuous autooscillations in a coupled atmosphere—ocean —continent ice model

Abstract

Climatic variability arising from nonlinear interaction between atmosphere, ocean and continental ice is studied. Analitical and numerical solutions of the evolution equations are presented. These solutions testify to the existence of discontinuous autooscillations of the climatic system. A prominent feature of these autooscillations is the alternation of slow and jump—wise variations of ocean thermohaline circulation intensity and direction. The slow variations occur for a time of about 10 x 10³ years in the regime of normal (present) circulation and for a time of about 50 x 10³ years in the regime of abnormal (reverse) circulation. Transition from one regime to another is performed practically instantly (for a time of about 10³ years) and is stipulated by jump-wise variations of the salinity differences. The ocean-averaged temperature and salinity as well as continental ice mass undergo the slow asymmetric oscillations without jumps.