中国南部对流层中上层臭氧增加的气象场判识及臭氧变化的多尺度特征

Identifying method of ozone enhancement and multi-scale characteristics of ozone change in the mid-upper troposphere over South China

副热带急流对中国南部地区对流层中上层臭氧浓度的影响程度及地理范围目前还研究较少,且缺乏综合使用常规气象资料及卫星资料来判识对流层中上层臭氧浓度增高的方法.本文利用NCEP再分析与最终分析资料、日本GMS-5地球静止卫星水汽云图资料,以2001年3月27～29日中国南部的临安、昆明、香港臭氧探测个例为基础,结合1996年3月29日香港与2001年4月13日临安对流层中上层高浓度臭氧分布个例对副热带急流对中国南部对流层中上层臭氧浓度的影响进行了详细分析,提出根据气象要素场判识春季中国南部对流层中上层臭氧浓度增高的充分条件为根据卫星水汽图像上的暗区、高空急流入口区的左侧辐合区、高空锋区、对流层中上层≥1PVU的向下伸展的舌状高位涡区来综合判断.本文的分析结果表明,本文个例中对流层中上层高浓度臭氧来自平流层;香港对流层中上层低浓度臭氧来自热带海洋地区.不仅臭氧垂直廓线的多个极小与极大值表明臭氧垂直分布的多尺度变化特征,而且对流层中上层PV分布以及卫星水汽图像分析也表明大气中的多尺度运动对臭氧垂直分布特征有显著影响.本文的结果表明与副热带高空急流相联系的平流层空气侵入不仅发生在中国大陆的较高纬度地区,较低纬度的昆明与香港地区也有平流层空气侵入导致对流层中上层臭氧浓度升高.

Not only there are fewer studies on the influence of subtropical upper jet stream on the ozone distribution in the mid- and upper troposphere over South China, but also there is no comprehensive method to identify the ozone enhancement in the mid- and upper troposphere using the conventional meteorological and satellite data. Ozone enhancement and loss were observed in the mid- and upper troposphere over Lin＇an, Kunming and Hong Kong on 27 and 29 March 2001 using the electric chemical cell （ECC） ozonesondes, and the upper tropospheric ozone enhances over Hong Kong on 29 March 1996 and over Lin＇an on 13 April 2001. Based on the data of NCEP reanalyses and final analyses, GMS-5 water vapor imagery, the enhanced ozone source and the multi-scale characteristics of ozone change in the mid- and upper troposphere over South China are analyzed. Furthermore, the sufficient conditions of meteorological fields are proposed as follows to identify ozone enhancement in the mid- and upper troposphere over South China in springtime： dark areas in the water vapor imagery of satellite, convergent areas on the left of upper jet stream, upper frontal areas, and high PV（≥1 PVU） areas in the mid- and upper troposphere. The results show that the enhanced ozone in the mid- and upper troposphere over South China is from stratosphere through the folding dynamic tropopause or broken thermal tropopause in the cases of Hong Kong 29 March 1996, Kunming 27 March 2001, Lin＇ an 29 March and 13 April 2001. For the case of Hong Kong on 27 and 29 March 2001, the enhanced ozone comes from stratosphere over midlatitudes and the low ozone is from the air mass over tropical ocean. Not only the minima and maxima of the ozone vertical distribution can indicate the multi-scale characteristic of ozone change, but also the case of Lin＇ an on 27 March 2001 shows that the atmospheric multi-scale circulations have an obvious impact on the vertical ozone distribution by means of the analyses of potential vorticity distribution and the GMS-5 water vapor images. The results in this paper also indicate that the intrusion of stratospheric air to the mid- and upper troposphere occurs not only in the higher latitudes but also in the lower latitudes （in this paper over Kunming and Hong Kong） over South China.