Parhomenko

pp. 41-57

The paper presents and discusses experimental results of joint calculations using a 3D atmospheric general circulation model, an upper layer ocean model, and a sea ice evolution model for arctic region. To analyze a sea ice cover evolution the calculations are performed. The paper gives maps of calculated sea ice cover distributions in the Arctic Region for different seasons. It analyzes the sea ice cover sensitivity to the basic parameters of models. These parameters define interaction between the atmosphere, ice, and ocean, namely sensible heat flux from sea ice and snow surface, heat flux from ocean to ice. The spatial and seasonal structure of changes has rather complex non-uniform character; there are great areas of opposite changes. It is connected with nonlinear behavior of feedback and interactions in model system including an atmosphere, sea ice, and ocean.

Influence of important climate parameters (atmosphere CO₂ concentration, solar constant), configuration of continents, as well as distribution of ocean depths corresponding to the considered time periods, on climate was investigated. The author used a global climate model that includes a 3D model of the thermohaline circulation of the ocean, an energy and moisture balance model of the atmosphere and a sea ice evolution model. Numerical experiments corresponding to periods of 124 million years ago and 200 million years ago with drastically different parameters were carried out. It was established that a stationary climate system state is achieved after 1500-2000 years of development. General global and spatial climatic characteristics for the atmosphere, oceans and sea ice were obtained. Estimated global mean atmospheric temperature is agreed with the reconstructed observed data. Features of the ocean circulation were studied for the corresponding periods.