Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

I. V. Mingalev et al. north-west direction for a distance of about 600 km. Simultaneously, the second cyclonic vortex arose, with its center being close to the southern edge of the initial intertropical convergence zone. Thus, to a moment o f 70 hours after the beginning of calculations, a pair o f cyclonic vortices arose in the vicinity of the intertropical convergence zone. The rotational centers of these cyclonic vortices are situated near the edges of the inetatropical convergence zone. The center o f the first cyclonic vortex is close to the northern edge while the center of the second cyclonic vortex is close to the southern edge of the intertropical convergence zone. The horizontal wind velocity in these cyclonic vortices achieved values of 15-20 m/s during the period o f seventy hours. The radii of these cyclonic vortices are about 600 km. It can be noticed that the results of observation of the Earth’s atmosphere indicated a simultaneous origin of twin tropical cyclones sometimes [Chen et a l, 2010]. The results of simulation indicate that a key factor in the modeled formation of twin tropical cyclonic vortices is the origin of a convexity in the configuration of the intertropical convergence zone, having the specific form, which is accompanied by asymmetric horizontal velocity field in the vicinity of this zone. The pointed out factors lead to beginning of instability of stream air flow. As a consequence, a pair of cyclonic vortices arises in the lower atmosphere in the course of time. A transformation of energy, emitted due to phase transitions o f water vapor to micro drops of water and ice particles in the mixture of air and water vapor moving upward, into kinetic energy of the air flow plays an important role in the increase of the horizontal wind velocity in the course of time. Conclusions A regional non-hydrostatic mathematical model of the wind system of the lower atmosphere, developed recently in the Polar Geophysical Institute, was utilized to investigate the initial stage o f the origin of large-scale vortices at tropical latitudes. The mathematical model is based on the numerical solution o f the system of transport equations containing the equations of continuity for air and for the total water content in all phase states, momentum equations for the zonal, meridional, and vertical components of the air velocity, and energy equation. The model produces three-dimensional distributions of the atmospheric parameters in the height range from 0 to 15 km over a limited region of the Earth's surface. Simulations were performed for the case when this region is intersected by the intertropical convergence zone. It was supposed that, at the initial moment, the intertropical convergence zone contains the convexity in the north direction, moreover, the zonal wind velocities at more northern latitudes relatively the centerline of the intertropical convergence zone are larger than those at more southern latitudes relatively it, with the west crook of the convexity being sharp while the east crook o f the convexity being gently sloping. Simulation results indicated that the twin tropical cyclones were formed during the period for about three days. The cyclones were formed one after another in the course of time. The rotational center of the first cyclone is close to the northern edge while the center of the second cyclone is close to the southern edge of the initial intertropical convergence zone to a moment of 70 hours after the beginning o f calculations. The radii of these cyclones are about 600 km. The horizontal wind velocity in the cyclones achieved values of 15-20 m/s during the period of about three days. A cknow ledgm en ts. This work was partly supported by the RFBR grant 13-01-00063. References Belotserkovskii, O .M , I.V. Mingalev, V.S. Mingalev, O.V. Mingalev, and A.M. Oparin, Mechanism o f the appearance of a large-scale vortex in the troposphere above a nonuniformly heated surface, Doklady Earth Sciences, 411(8), 1284-1288, 2006. Belotserkovskii, O .M , I.V. Mingalev, V.S. Mingalev, O.V. Mingalev, A.M. Oparin, and V.M. Chechetkin, Formation of large-scale vortices in shear flow of the lower atmosphere o f the Earth in the region of tropical latitudes, Cosmic Research, 47(6), 466-479, 2009. Chen, T .-C , J.-D Tsay, M.-C. Yen and E.O. Cayanan, Formation of the Philippine twin tropical cyclones during the 2008 summer monsoon onset, Weather and Forecasting, 25(5), 1317-1341, 2010. Mingalev, I.V. and V.S. 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