The air temperature change over the Tibetan Plateau during 1979-2002 and its possible linkage with ozone depletion

Using radiosonde data and satellite observations, we investigated the air temperature change over the Tibetan Plateau in the period of 1979-2002. It is shown that the air temperature in the lower stratosphere and upper troposphere was out of phase with that in the middle and lower troposphere. The temperature decreased and a decreasing trend appeared in the lower stratosphere and upper troposphere. The amplitude of the temperature decrease in both the annual and the seasonal mean over the Tibetan Plateau was larger than that of the global atmosphere. In the middle and lower troposphere over the Tibetan Plateau, the temperature increased and the increasing trend was stronger than that over the regions in the same latitudes in eastern China. Meanwhile, an analysis of the satellite observed ozone data in the same period of 1979-2002 shows that over the Tibetan Plateau, the total ozone amount declined in each season, and the ozone depleted the most compared to other regions in the same latitudes. Thus, the ultraviolet radiation absorbed in the lower stratosphere and upper troposphere over the Tibetan Plateau becomes less than that over other regions in the same latitudes, and more ultraviolet radiation could enter into the troposphere. This may result in a strong cooling in the lower stratosphere and upper troposphere and an intense warming in the middle and lower troposphere over the Tibetan Plateau. Therefore, the more serious depletion of the ozone over the Tibetan Plateau possibly explains why the air temperature change over the Tibetan Plateau differs from that over other regions in the same latitudes.