对流层顶变化对上对流层/下平流层臭氧分布的影响

上对流层和下平流层(UT／LS)，位于8-25km高度之间，是大气中一个很特殊的区域．大部分的臭氧分布在下平流层，在下平流层臭氧的含量发生一个很小的变化，就会对气候和地面的紫外辐射产生很大的影响．而作为气象参数的对流层顶，是充分混合、缺乏臭氧的上对流层和层结稳定、臭氧丰富的下平流层之间的边界或过渡层，其变化对臭氧总量和分布有直接和明显的影响．本文使用二维模式模拟研究对流层顶变化对臭氧在UT／LS分布的影响．模拟结果表明对流层顶的季节变化对UT/LS的臭氧分布有明显的影响，臭氧的局地变化可以超过10％在冬季北半球中纬度对流层顶高度升高1km时，模式结果表明对臭氧分布的影响比较显著，局地变化可超过6％，但是对臭氧总量的影响较小，变化不超过5DU，小于观测资料统计分析的结果。

THE IMPACT OF TROPOPAUSE VARIATION ON OZONE DISTRIBUTION IN UPPER TROPOSPHERE/LOWER STRATOSPHERE

The upper troposphere/lower stratosphere (UT/LS), as a special region, lies between 8 and 25 km altitude. Because most of ozone column resides in the lower stratosphere, small change in ozone abundance could have a large impact on climate and the surface UV flux. The tropopause, as an interface or transition zone between the well mixed, ozone-poor upper troposphere and the stratified, ozone rich lower stratosphere, has its seasonal and long-term variation trends which in turn could lead to a direct and evident effect on the distribution of atmospheric ozone and its column abundance. This work simulated the impact of tropopause variation on the distribution of ozone in UT/LS with a two-dimensional model named SOCRATES (Simulation Of Chemistry, Radiation, And Transport of Environmentally important Species). The model, developed in the Division of Atmospheric Chemistry of NCAR, is one coupling chemical, radiative, and dynamical processes. Its domain and resolution are 0-120 km and 1 km in vertical and 85S-85N and 5?in horizontal. Model simulation results show that the annual cycle of the tropopause height has remarkable impact on the ozone distribution in the UT/LS. The local change of ozone can be more than 10%. When the tropopause is increased by 1 km in winter in middle latitudes of Northern Hemisphere, the impact on ozone distribution is evident and the local change of ozone can be more than 6%. However the impact on total ozone is relatively small, less than 5 Dobson units. This is much less than the statistic results between tropopause height and total ozone from data analysis.