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 [1–11]). 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 [12–16]). Thus, it is necessary to use more complex general circulation models, describing the vertical
References
[1]
S. Manabe and D. G. Hahn, “Simulation of atmospheric variability,” Monthly Weather Review, vol. 109, no. 11, pp. 2260–2286, 1981.
[2]
D. Cariolle, A. Lasserre-Bigorry, J. F. Royer, and J. F. Geleyn, “A general circulation model simulation of the springtime antarctic ozone decrease and its impact on mid-latitudes,” Journal of Geophysical Research, vol. 95, no. 2, pp. 1883–1898, 1990.
[3]
P. J. Rasch and D. L. Williamson, “The sensitivity of a general circulation model climate to the moisture transport formulation,” Journal of Geophysical Research, vol. 96, article D7, pp. 123–137, 1991.
[4]
H. F. Graf, I. Kirchner, R. Sausen, and S. Schubert, “The impact of upper-tropospheric aerosol on global atmospheric circulation,” Annales Geophysicae, vol. 10, pp. 689–707, 1992.
[5]
P. A. Stott and R. S. Harwood, “An implicit time-stepping scheme for chemical species in a Global atmospheric circulation model,” Annales Geophysicae, vol. 11, pp. 377–388, 1993.
[6]
B. Christiansen, A. Guldberg, A. W. Hansen, and L. P. Riishojgaard, “On the response of a three-dimensional general circulation model to imposed changes in the ozone distribution,” Journal of Geophysical Research D, vol. 102, no. 11, pp. 13051–13077, 1997.
[7]
V. Y. Galin, “Parametrization of radiative processes in the DNM atmospheric model,” Izvestiya, Atmospheric and Ocean Physics, vol. 34, no. 3, pp. 339–347, 1998 (Russian).
[8]
A. L. Gibelin and M. Déqué, “Anthropogenic climate change over the mediterranean region simulated by a global variable resolution model,” Climate Dynamics, vol. 20, no. 4, pp. 327–339, 2002.
[9]
M. Mendillo, H. Rishbeth, R. G. Roble, and J. Wroten, “Modelling f2-layer seasonal trends and day-to-day variability driven by coupling with the lower atmosphere,” Journal of Atmospheric and Solar-Terrestrial Physics, vol. 64, no. 18, pp. 1911–1931, 2002.
[10]
M. J. Harris, N. F. Arnold, and A. D. Aylward, “A study into the effect of the diurnal tide on the structure of the background mesosphere and thermosphere using the new coupled middle atmosphere and thermosphere (cmat) general circulation model,” Annales Geophysicae, vol. 20, no. 2, pp. 225–235, 2002.
[11]
U. Langematz, A. Claussnitzer, K. Matthes, and M. Kunze, “The climate during the maunder minimum: a simulation with the freie universit？t berlin climate middle atmosphere model (fub-cmam),” Journal of Atmospheric and Solar-Terrestrial Physics, vol. 67, no. 1-2, pp. 55–69, 2005.
[12]
S. Peteherych, G. G. Shepherd, and J. K. Walker, “Observation of vertical e-region neutral winds in two intense auroral arcs,” Planetary and Space Science, vol. 33, no. 8, pp. 869–873, 1985.
[13]
H. U. Widdel, “Vertical movements in the middle atmosphere derived from foil cloud experiments,” Journal of Atmospheric and Terrestrial Physics, vol. 49, no. 7-8, pp. 723–741, 1987.
[14]
U. P. Hoppe and T. Hansen, “Studies of vertical motions in the upper mesosphere using the EISCAT UHF radar,” Annales Geophysicae, vol. 6, pp. 181–186, 1988.
[15]
G. D. Price and F. Jacka, “The influence of geomagnetic activity on the upper mesosphere/lower thermosphere in the auroral zone. i. vertical winds,” Journal of Atmospheric and Terrestrial Physics, vol. 53, no. 10, pp. 909–922, 1991.
[16]
M. Ishii, “Relationship between thermospheric vertical wind and the location of ionospheric current in the polar region,” Advances in Polar Upper Atmosphere Research, vol. 19, pp. 63–70, 2005.
[17]
I. V. Mingalev and V. S. Mingalev, “The global circulation model of the lower and middle atmosphere of the Earth with a given temperature distribution,” Mathematical Modeling, vol. 17, pp. 24–40, 2005 (Russian).
[18]
I. V. Mingalev, V. S. Mingalev, and G. I. Mingaleva, “Numerical simulation of the global distributions of the horizontal and vertical wind in the middle atmosphere using a given neutral gas temperature field,” Journal of Atmospheric and Solar-Terrestrial Physics, vol. 69, no. 4-5, pp. 552–568, 2007.
[19]
I. V. Mingalev, O. V. Mingalev, and V. S. Mingalev, “Model simulation of the global circulation in the middle atmosphere for january conditions,” Advances in Geosciences, vol. 15, pp. 11–16, 2008.
[20]
J. M. Picone, A. E. Hedin, D. P. Drob, and A. C. Aikin, “Nrlmsise-00 empirical model of the atmosphere: statistical comparisons and scientific issues,” Journal of Geophysical Research A, vol. 107, no. 12, article 1468, 16 pages, 2002.
[21]
A. M. Obukhov, Turbulence and Dynamics of Atmosphere, Hydrometeoizdat, Leningrad, Russia, 1988.
[22]
A. K. Smith, R. R. Garcia, D. R. Marsh, and J. H. Richter, “WACCM simulations of the mean circulation and trace species transport in the winter mesosphere,” Journal of Geophysical Research D, vol. 116, no. 20, Article ID D20115, 17 pages, 2011.
[23]
R. E. Cahalan, G. Wen, J. W. Harder, and P. Pilewskie, “Temperature responses to spectral solar variability on decadal time scales,” Geophysical Research Letters, vol. 37, Article ID L07705, 5 pages, 2010.
[24]
A. I. Semenov, N. N. Shefov, and V. A. Sukhodoev, “Re-analysis of the long-term hydroxyl rotational temperature trend according to measurements in Spitsbergen,” in Proceedings of the 29th Annual Seminar on Physics of Auroral Phenomena, Polar Geophysical Institute, Apatity, Russia, 2007.
