Numerical experiments on paleoclimate modeling

Abstract

The influence of climatic parameters (values of CO2 concentration in the atmosphere, solar constant), the configuration of continents, as well as the distribution of the depths of the World Ocean, characteristic of the time periods under consideration, on the climate is investigated. A global climate model is used, including a model of three-dimensional thermohaline circulation of the ocean, an energy-moisture balance model of the atmosphere and a model of the sea ice evolution. Numerical experiments have been carried out to model the climate corresponding to the periods 120.4 million years ago and 200 million years ago with sharply different parameters. The first interval was characterized by high CO2 concentrations and a continent lying in meridional direction. During the second interval a super continent was located in the Northern polar region extending to the South but not reaching the South Pole. Calculations show that the average global climatic characteristics achieve to a stationary regime during about 1500-2000 years. The main global and spatial climatic characteristics for the atmosphere, ocean, and sea ice are obtained. The estimated average global atmospheric temperature falls within the limits reconstructed from observations. The features of ocean circulation for the corresponding periods are studied.