青藏高原气温变化趋势与同纬度带其他地区的差异以及臭氧的可能作用

利用台站探空观测资料和卫星观测资料,分析了1979—2002年青藏高原上空温度的变化趋势。结果表明:高原地区上空平流层低层和对流层上层的温度与对流层中低层具有反相变化趋势。平流层低层和对流层上层降温,温度出现降低趋势,降温幅度无论是年平均还是季节平均都比全球平均降温幅度更大。高原上空对流层中低层增温,温度显示出增加的趋势,并且比同纬度中国东部非高原地区有更强的增温趋势。对1979—2002年卫星臭氧资料的分析表明,青藏高原上空臭氧总量在每个季节都呈现出明显的下降趋势,并且比同纬度带其他地区下降得更快。由于青藏高原上空臭氧有更大幅度的减少,造成高原平流层对太阳紫外辐射吸收比其他地区更少,使进入对流层的辐射更多,从而导致高原上空平流层低层和对流层上层降温比其他地区更强,而对流层中低层增温更大。因此,高原上空比其他地区更大幅度的臭氧总量减少可能是造成青藏高原上空与同纬度其他地区温度变化趋势差异的一个重要原因。

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.