【摘要】 文中分析了 1996年 8月 1日发生在西宁 (36 .4 3°N ,10 1.4 5°E ,海拔 :2 2 96m)地区对流层异常臭氧次峰现象。观测资料揭示了高空低压槽东移是臭氧次峰的主要天气特征。三维后向轨迹计算表明 ,尽管代表臭氧次峰的气团可以追溯到中亚地区 ,但是明显的气团向下输送则发生在新疆、青海间的高空低压槽内。中尺度模拟进一步确认了对流层顶折叠和平流层向下输送是臭氧次峰出现的动力机制。臭氧次峰在对流层高度位置与准无辐散层有关更多还原

【Abstract】 A case study on the ozone downward transport from stratosphere to troposphere over Xining(36.43°N, 101.45°E, 2296 m asl)on August 1st, 1996 has been given out by the methods of observational analysis, 3 dimensional backward trajectory calculation and the mesoscale modeling. Routine radiosonde data show that the main synoptic characteristics of this case were the easterly shift of the trough in the upper troposphere. As a result of the synoptics, a pronounced ozone peak was detected around 7 km over Xining. 3 dimensional trajectory calculations imply that the air parcels of ozone peak around 7 km may be traced to the middle Asia region, but the distinguished downward transport from stratosphere to troposphere induced was over the region from Xinjiang to Qinghai. Furthermore, mesoscale simulation confirms that the temporal and spatial evolution of tropopause folding indexed by the potential vorticity is the critical mechanism of such downward incursion. The modeling work also shows that the altitude of tropospheric ozone peak was associated with stable quasi zero divergence layer, which reflects the temporal dynamical balance in troposphere.更多还原