Abstracts

Plenary talks

In the report, a retrospective review concerning developing mathematical models of general circulation of the atmosphere and ocean is presented. Such models form the basis of the present-day global models of climate. Grounding on experience achieved in the Computer Centre of the Siberian Branch of the USSR Academy of Sciences (now, Institute of Computational Mathematics and Mathematical Geophysics, Novosibirsk) and in the Institute for Numerical Mathematics, Russian Academy of Sciences (INM RAS, Moscow), basic methodological aspects related to the development of such models are discussed and some results of their applications are presented. The basic results achieved to this time can be summarized as follows.

1. A complex of models of general circulation of the atmosphere (troposphere+stratosphere+mesosphere) with different spatial resolution is developed. Some of these models are implemented at modern computational systems of the parallel architecture. Numerical experiments to simulate the present-day climate (the sea surface temperature and the distribution of sea and continental ice are prescribed accordingly to observations for the period 1979-1998) have been carried out within the frame of international projects of atmospheric models intercomparison, AMIP-I and AMIP-II, and have shown a high quality in reproducing climate characteristics. In particular, it was in first time possible to simulate and reproduce feedback between climate changes and dynamics of the permafrost active layer. It should be noted that in these projects, more than 30 models from Australia, Great Britain, Germany, Canada, Russia, USA, France, Japan and other countries have been employed.

2. On the basis of new effective numerical methods which employ implicit splitting-up schemes and a combination of finite – difference and finite – element spatial approximations, the World Ocean general circulation model is constructed. This model has a number of significant additional possibilities: numerical grids of the different spatial structure may be used; the viscosity and diffusivity coefficients may be prescribed in a broad diapason of their variations; there is a possibility to carry out stable calculations in the regime of “"small" viscosity”. The latter is impossible for many known models of the ocean general circulation. Using this model, the present-day climate of the World Ocean is reproduced.

3.On the basis of the atmospheric and oceanic general circulation models, a global climate model is constructed. A high quality of this model is demonstrated within the frame of the project of intercomparison of coupled atmosphere – ocean models (CMIP). The model developed at INM has satisfactorly reproduced such specific phenomena as statistics for the El'-Nin'o events, response of the atmospheric circulation on this phenomenon, arctic oscillations and other fundamental properties of the atmospheric and oceanic circulation.

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