东亚地区平流层、对流层交换对臭氧分布影响的模拟研究

Simulation of Stratosphere-Troposphere Exchange Effecting on the Distribution of Ozone over Eastern Asia

首先将区域酸沉降模式 (RADM)进行改造 ,加入平流层化学模块以替代对流层模块。然后用MM5单向耦合改造后的化学模式M RADM ,对东亚地区一次切断低压( 2 0 0 0年 4月 8～ 1 2日 )引起的对流层顶折叠对上对流层、下平流层臭氧分布形式的影响进行模拟。结果显示 :( 1 )随着高空槽的发展与切断 ,高空槽的底部及切断低压四周臭氧有显著增加。对流层顶折叠使高空臭氧向下输送 ,这种向下的输送可以到达对流层中部 ,对上对流层的臭氧影响最大。 ( 2 )模式可以成功地模拟出在北京地区探测到的臭氧垂直廓线的双峰结构。 2 5 0hPa处的臭氧分压比背景值增加近 5倍。模拟表明改造后的区域化学模式M RADM可以用于研究天气过程引起的对流层顶附近臭氧的演变情况。 ( 3)上对流层臭氧分布形势的变化主要是由动力过程中的水平平流作用引起的 ,但是对流层顶附近臭氧的化学过程是不可忽略的。

First, the Regional Acid Deposition Model RADM was rebuild using a stratospheric chemical scheme instead of the tropospheric chemical scheme. Then the mesoscale model MM5 is applied to simulate the stratosphere troposphere exchange processes due to the tropopause folding effecting on the distribution of ozone in eastern Asia on 8～12 April 2000. The results show: 1) Along with the development and cut off of the upper trough, ozone in the bottom of the trough and around the low has high concentration. The downward transport of ozone due to tropopause folding can reach middle part of troposphere, which has the most influence on the ozone in the upper troposphere. 2) The double peaks structure of ozone profile in the upper troposphere in Beijing could be successfully simulated, which is comparable with observation data. The concentration of ozone in 250 hPa increases about 5 times then initial value. Simulated results show that M RADM can be used to study the influence of weather system on the distribution of ozone near tropopause. 3) Horizontal advection is the primary contributor to the distribution of ozone in the upper troposphere. But the chemisical processes near the tropopasue cannot be completely ignored.