NUMERICAL MODELING OF EXTREME CONDITIONS OF PLANETARY ATMOSPHERE

Abstract

The atmospheric general circulation plays an important role in the formation of weather and climate processes, providing transport and redistribution of heat, moisture, and angular momentum. Climate changes can have a significant effect on the elements of the atmospheric general circulation. To understand the general circulation patterns and possible future changes in its components, it is important to study its state under the limiting properties of the geographic envelope, in particular, the type of the active layer. The paper presents the results of numerical modeling of the atmospheric general circulation under simplified conditions of the underlying surface, namely oceanic and desert surfaces. The numerical experiment was performed on a global model transformed from the WRF-ARW model and it reproduced the atmosphere dynamics during one year. The limiting scenarios – either global ocean or global desert – reflected the role of phase transitions in the Earth's atmosphere. In the first case, due to the greenhouse effect, the circulation is not pronounced owing to the absence of a significant interlatitudinal gradient. In the second case, the sandy surface, unlike the ocean, cannot accumulate a large amount of heat, so the air near the Earth's surface cools rapidly in thewinter hemisphere and heats up rapidly in the summer hemisphere, as a result of which there are no trade winds. The combination of oceanic and desert zones (all homogeneous along the meridian) leads to the situation that the large-scale atmospheric circulationacquires features close to those of the Earth, which allows us to consider this configuration as a basic one for further numerical experiments. The experiments have shown the leading role of the absorbed part of solar radiation (insolation) and the contribution of water vapor (greenhouse effect, release of latent heat) in the formation of large-scale atmospheric currents. The implemented WRFARW model can be successfully used for modeling the general circulation of the atmosphere under different initial and boundary conditions.