Physics of auroral phenomena : proceedings of the 38th annual seminar, Apatity, 2-6 march, 2015 / [ed. board: A. G. Yahnin, N. V. Semenova]. - Апатиты : Издательство Кольского научного центра РАН, 2015. - 189 с. : ил., табл.

Numerical modeling o f the influence ofgeomagnetic activity on the global circulation o f the Earth's atmospherefor July conditions atmospheric temperature on the geomagnetic activity below approximately 80 km, the influence of the geomagnetic activity level on the global circulation of the stratosphere and mesosphere do exist. To explain this fact, let us consider the global distributions of the simulated vertical component of the neutral wind velocity, calculated for three distinct values of geomagnetic activity. It turns out that these distributions are rather distinct not only at levels of the lower thermosphere but also at levels of the stratosphere and mesosphere (Fig. 2). Consequently, the vertical transport exists of the air from the lower thermosphere to the mesosphere and stratosphere and vice versa. This transport is influenced by geomagnetic activity conditions. Thus, the influence of geomagnetic activity on the global circulation in the Earth’s stratosphere and mesosphere for July conditions may be explained by the vertical transport of the air which may be noticeably different under distinct geomagnetic activity conditions. The simulation results, obtained in the present study for July conditions, are similar to the results of simulation, obtained earlier for January conditions, as for the cause of the influence of geomagnetic activity on the global circulation in the Earth’s stratosphere and mesosphere. Conclusion The non-hydrostatic model of the global neutral wind system of the Earth’s atmosphere, developed earlier in the Polar Geophysical Institute, was utilized to investigate how geomagnetic activity affects the global circulation of the atmosphere for July conditions. The model produces three-dimensional distributions of the zonal, meridional, and vertical components of the neutral wind and neutral gas density in the layer surrounding the Earth globally and stretching from the ground up to the altitude of 126 km. 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, i.e. the input parameter of the model, and obtained from the NRLMSISE- 00 empirical model. Simulations are performed for three distinct values of geomagnetic activity (Kp=l, 4, and 7). The simulation results indicate that, in the lower thermosphere, geomagnetic activity ought to influence considerably on the formation of global neutral wind system as a consequence of variations of the atmospheric temperature distributions due to geomagnetic activity changes. At levels of the stratosphere and mesosphere, the influence of geomagnetic activity on the global distribution of the atmospheric temperature ought to be absent, nevertheless, the effect of geomagnetic activity on the global circulation of the atmosphere exists at these levels. The influence of geomagnetic activity on the global neutral wind system in the stratosphere and mesosphere is conditioned by the vertical transport of the air which may be noticeably different under distinct geomagnetic activity conditions. The explanation of the influence of geomagnetic activity on the global circulation in the Earth’s stratosphere and mesosphere, propounded in the present study for July conditions, is similar to the elucidation, given earlier for January conditions. It can be emphasized that the applied mathematical model was able to simulate this effect due to the fact that the model is non-hydrostatic. Acknowledgements. This work was partly supported by the Presidium of the RAS through the Program No. 9 and by Grant No. 13-01-00063 from the Russian Foundation for Basic Research. References Mingalev, I.V., Mingalev, V.S. (2005) The global circulation model of the lower and middle atmosphere of the Earth with a given temperature distribution, Mathematical Modeling, 17(5), 24-40 (in Russian). Mingalev, I.V., Mingalev, V.S., Mingaleva, G.I. (2007) Numerical simulation of global distributions of the horizontal and vertical wind in the middle atmosphere using a given neutral gas temperature field, J. Atmos. Sol.- Terr. Phys., 69, 552-568. Mingalev, I., Mingaleva, G., Mingalev, V. (2013) A simulation study of the effect of geomagnetic activity on the global circulation in the Earth’s middle atmosphere. Atmospheric and Climate Sciences 3 8-19 doi: 10.4236/acs.2013.33A002, Mingalev, I.V., Orlov, K.G., Mingalev, V.S. (2014) A computational study of the transformation of global gas flows in the Earth’s atmosphere over the course of a year. Open Journal o f Fluid Dynamics, 4, 379-402, http://dx.doi. org/10.4236/ojfd.2014.44029. Picone, J.M., Hedin, A.E., Drob, D.P., Aikin, A.C. (2002) NRLMSISE-00 empirical model of the atmosphere: Statistical comparisons and scientific issues,/. Geophys. Res., 107A, (SIA 15) 1-16. 106