The Seasonal Changes And Inter-annual Features Of The Arctic Stratospheric Ozone In Recent Years

Ozone is a kind of important trace gases in the earth's atmosphere, which greatly impacts the life of human. The discovery of the ozone hole over Antarctic makes ozone loss in the stratosphere a global hot issue, and Arctic ozone reduction has more potential threats. This will lead to increasing ultraviolet in northern Europe, and father north, more influential. In addition, the affected areas may also include North America with dense population, even including the northeast of China and Xinjiang region.This paper makes comprehensive use of ozone total and profile data, the NCEP reanalysis data and the circulation indices, and analyzes the characteristics of the global and Tibetan Plateau ozone in recent years. It focuses on the research of the differences of Antarctic and Arctic ozone, the natural causes leading to it, the rule of the season change and the interannual variation, and the arctic ozone depletion mechanism from the end of the winter to the early spring, and speculates the reason of the arctic ozone low value.The distribution of the global total ozone is uneven, while the minimum appears in the equator. The amount of total ozone in the southern hemisphere is smaller than the northern hemisphere, due to the atmospheric circulation and vortex meridional transportation. The total ozone both in the southern hemisphere and the northern hemisphere is highest in the spring and lowest in the autumn, and increases in the winter and decline in the summer. The total ozone in is highest in the spring and lowest in the autumn, and in four seasons comparing with the no mountain region in the same latitudes is a low value center which is lowest in summer. In the winter Tibetan Plateau is controlled by downdrafts, while in the summer is updrafts. In the summer the upper troposphere and the low stratosphere of Tibetan Plateau is under the control of powerful South Asian High with the airflow divergent. This situation is conductive to the material around to the plateau and the pollutants in low altitude convergence, and then up to the low stratosphere divergence. The lower stratosphere of Tibetan Plateau can appear very low temperature. So, low concentration ozone in the troposphere layer conveying to the stratosphere and the physical and chemical process consuming ozone may cause total ozone value abnormally low.Antarctic keeps an ozone low value center throughout the year. Antarctic Ozone Hole forms with large scale from the end of winter to the early spring, and return to the normal level until the eerily summer. In the autumn and the winter, Antarctic ozone slightly reduces. The arctic ozone reduction is accompanied by the whole spring and summer, and the total ozone value reaches lowest in the autumn, with a weak low value center. The arctic ozone largely recoveries in the winter. This is mainly caused by the natural factors such as the differences between the northern and southern hemispheres circulation, and the planetary wave diversity. We divide the arctic into two regions, and find that the total ozone value in the west is lower than that of the east, which is obvious from the end of the autumn to the early spring. This fact has a very good corresponding relation with the 50hpa polar vortex position, for the total ozone value in the polar vortex is lower than other regions. The air in the polar vortex exchanges weakly with outside, leading to the inside ozone value reducing without ozone supplement. The arctic appeared uncommon and serious spring ozone low value center in 1997 and 2011, corresponding to in the spring of both two years the arctic polar vortex of heavier intensity and lower temperature in 50hpa altitude comparing to other years. This may relate to the heterogeneous reactions occurring in the polar stratospheric clouds. The strong polar vortex existing in the arctic spring is a necessary condition for the appearance of the arctic ozone abnormal low value.