A Computational Study of the Transformation of Global Gas Flows in the Earth’s Atmosphere over the Course of a Year

A mathematical model, developed earlier in the Polar Geophysical Institute, is applied to investigate the transformation of global gas flows in the Earth’s atmosphere over the course of a year. The model is based on the numerical solution of the system of gas dynamic equations. The mathematical model produces three-dimensional distributions of the gas dynamic parameters of the atmosphere in the height range from 0 to 126 km over the Earth’s surface. To investigate the seasonal transformation of the global circulation of the lower and middle atmosphere, simulations are performed for conditions corresponding to twelve dates, which belong to twelve different months. Results of simulations indicate that the variations of the solar illumination of the Earth’s atmosphere, conditioned by different positions of the Earth along its trajectory around the Sun, influence considerably the transformation of the planetary circulation of the lower and middle atmosphere over the course of a year.

Results of Numerical Modeling of the Origin of Cyclones and Anticyclones in the Vicinity of the Intertropical Convergence Zone

A review of simulation results, devoted to time-dependent modeling of the initial stage of the formation of large-scale vortices in the troposphere in the vicinity of the intertropical convergence zone, is presented. The simulation results were obtained not long ago with the help of the mathematical model of the neutral wind system of the lower atmosphere, developed earlier in the Polar Geophysical Institute. The utilized mathematical 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. Simulation results were obtained for the case when the limited three-dimensional simulation domain, situated at low latitudes, is intersected by an intertropical convergence zone in the west-east direction. The reviewed simulation results were obtained for various initial configurations of the intertropical convergence zone. Results of numerical modeling have indicated that the origin of convexities in the form of the intertropical convergence zone can lead to the formation of different large-scale vortices in the lower atmosphere, in particular, a tropical cyclone, pair of cyclonic vortices, pair of cyclonic-anticyclonic vortexes, and triplet of cyclonic vortices. The simulation results, obtained earlier and presented individually in various editions, are reviewed and summarized in the present paper. A physical mechanism, responsible for the formation of the simulated large-scale vortices in the vicinity of the intertropical convergence zone, is discussed.

Numerical Modeling of the Initial Formation of Cyclonic Vortices at Tropical Latitudes

To investigate the initial formation of large-scale vortices at tropical latitudes a regional non-hydrostatic mathematical model of the wind system of the lower atmosphere, developed earlier in the Polar Geophysical Institute, is utilized. 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 are produced by the utilized model. Simulations are performed for the case when the limited three-dimensional simulation domain is intersected by an intertropical convergence zone in the west-east direction. Simulation results indicated that the origin of two convexities in the north direction in the configuration of the intertropical convergence zone can lead to the formation of three distinct tropical cyclones during the period of about four days.

Numerical Modeling of the Influence of the Relief of a Planet on the Global Circulation of the Earth’s Stratosphere and Mesosphere

An investigation of the influence of the relief of a planet on the global circulation of the Earth’s atmosphere is an important problem. Beyond doubt, mountains affect the global circulation of the troposphere, however, their influence on the global circulation of the stratosphere and mesosphere is not evident. In the present study, to investigate the influence of the relief of a planet on the global circulation of the Earth’s stratosphere and mesosphere, the non-hydrostatic mathematical model, developed earlier in the Polar Geophysical Institute, is utilized. Calculations were made for two distinct cases. The relief of the planet was taken into account for the first case. Unlike, the Earth’s surface was assumed to be smooth for the second case. Simulations were performed for the winter period in the northern hemisphere (January). Simulation results, obtained for both considered cases, are qualitatively similar at the levels of stratosphere and mesosphere, however, some noticeable distinctions exist. The horizontal domains exist, where the simulated horizontal and vertical components of the neutral wind velocity, obtained for two considered cases, differ noticeably at the levels of the stratosphere and mesosphere. Some of these horizontal domains are not connected with positions of mountains at the Earth’s surface. On the contrary, some of these horizontal domains are situated above mountains.