%0 Journal Article
%T Numerical Modeling of the Influence of Solar Activity on the Global Circulation in the Earth¡¯s Mesosphere and Lower Thermosphere
%A Igor Mingalev
%A Victor Mingalev
%J International Journal of Geophysics
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/106035
%X The nonhydrostatic model of the global neutral wind system of the earth¡¯s atmosphere, developed earlier in the Polar Geophysical Institute, is utilized to investigate how solar activity affects the formation of the large-scale global circulation of the mesosphere and lower thermosphere. The peculiarity of the utilized model consists in that the internal energy equation for the neutral gas is not solved in the model calculations. Instead, the global temperature field is assumed to be a given distribution, that is, the input parameter of the model. Moreover, in the model calculations, not only the horizontal components but also the vertical component of the neutral wind velocity is obtained by means of a numerical solution of a generalized Navier-Stokes equation for compressible gas, so the hydrostatic equation is not applied. The simulation results indicate that solar activity ought to influence considerably on the formation of global neutral wind system in the mesosphere and lower thermosphere. The influence is conditioned by the vertical transport of air from the lower thermosphere to the mesosphere and stratosphere. This transport may be rather different under distinct solar activity conditions. 1. Introduction During the last three decades, several general circulation models of the lower and middle atmosphere have been developed (e.g., see [1¨C11]). It can be noticed that the existing general circulation models of the lower and middle atmosphere may be successfully utilized for simulation of the slow climate changes. Unfortunately, these models cannot produce the vertical atmospheric wind with an acceptable accuracy. The fact is that the momentum equation for the vertical velocity is omitted in commonly used general circulation models, and the vertical velocity is obtained with the help of simple hydrostatic equation. Unfortunately, these models can not produce the vertical atmospheric wind with an acceptable accuracy. As a consequence of the simplification, such models do not provide an ability to simulate the large-scale global circulation in all regimes, in particular, under disturbed conditions. As is well known, the global models just mentioned produce the vertical component of the wind velocity having the values of several centimeters per second at levels of the lower thermosphere. While the observed vertical velocity is known to achieve up to some tens m/s at levels of the mesosphere and lower thermosphere in high-latitude regions (see [12¨C16]). Thus, it is necessary to use more complex general circulation models, describing the vertical
%U http://www.hindawi.com/journals/ijge/2012/106035/