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.

spheroid whose radius at the equator is more than that at the pole. Upper boundary conditions provide the conservation law of mass in the simulation domain. More complete details of the utilized model may be found in the studies o i Mingalev and Mingalev [2005] and Mingalev et al. [2007]. Simulation results Simulation results to be presented in this work were obtained for the summer period in the northern hemisphere (16 July) and for conditions corresponding to moderate 10.7-cm solar flux (Fю. 7 = 101). Calculations were made for three distinct values of geomagnetic activity (Kp=l, 4, and 7). The steady-state distributions of the atmospheric parameters were obtained, using the method of establishment, that is, the variations of the atmospheric parameters with time were calculated until they become stationary on condition that inputs to the model and boundary conditions correspond to the fixed moment, namely, 10.30 UT. The temperature distributions, corresponding to this moment, were taken from the NRLMSISE-00 empirical model [Picone et al., 2002]. Analyzing these temperature distributions, obtained for three distinct values of geomagnetic activity (Kp=l,4, and 7), we can see that they are very similar below approximately 80 km, whereas, above this altitude, they may be rather different. Thus, it can be seen from the NRLMSISE-00 empirical model that the influence of level of geomagnetic activity on the global distribution of the atmospheric temperature ought to be absent at altitudes of the troposphere, stratosphere, and mesosphere, while this influence ought to be appreciable at altitudes of the lower thermosphere for the summer period in the northern hemisphere. Numerical modeling o fthe influence ofgeomagnetic activity on the global circulation o fthe Earth’s atmospherefo r M y conditions F ig u r e 1. The global distributions of the vector of the simulated horizontal component of the neutral wind velocity at the altitude of 50 km, obtained for 16 July and calculated for three distinct values of geomagnetic activity: Kp=l (top panel), Kp=4 (middle panel), and Kp=7 (bottom panel). The degree of shadowing of the figures indicates the module of the velocity in m/s. ■130 _____ __- ___________________ __ ________________________________ __ ______________ 120 ■,o 190 jSO J ?0 j60 The global distributions of the vector of ' _'-ЦЙ ■ « Изо I 20 К -7 the simulated horizontal component of the neutral wind velocity at the altitude ~'u Ц ,0 of 50 km, calculated with the help of the mathematical model and obtained for three distinct values of geomagnetic н-50 ют activity (Kp=l, 4, and 7), are shown in Fig. 1. The global distributions of the simulated vertical component of the neutral wind velocity at 50 km altitude, calculated for three distinct values of 3 geomagnetic activity (Kp=l, 4, and 7), "JU[ ~: : : : : : : : : ; r fT"1'1.1'" Щзо are shown in Fig. 2. It turns out that ’° --------- parameters, calculated with the help of the mathematical model, illustrate both Longitude common characteristic features and distinctions caused by different values of geomagnetic activity. Let us consider common features of the simulation results. The horizontal and vertical components of the wind velocity are changeable functions not only of the altitude but also of latitude and longitude. At levels of the troposphere, stratosphere, mesosphere, and lower thermosphere, maximal absolute values of the horizontal and vertical components of the wind velocity are larger at higher altitudes. At altitudes of the mesosphere and lower thermosphere, the horizontal domains exist where the steep gradients in the horizontal velocity field take place. At the near points, the horizontal wind velocity can have various directions which may be opposite. Also, the horizontal domains exist in which the vertical neutral wind component has opposite directions. The horizontal wind velocity 104 H*50km