北半球地面O_3的区域分布和变化特征

Characteristics of distribution and variation of surface O_3 in different areas of the northern hemisphere

利用来自GAW(Global Atmosphere Watch,全球大气监测)的、由WDCGG(World DataCentre for Greenhouse Gases,世界温室气体数据中心)收集整理和发布的、基于地基观测的北半球共15个站点的地面O3含量的逐月观测资料以及逐时观测资料,分析、对比并总结了北半球不同经纬度各区域的地面O3含量的年变化和各个季节的日变化规律.研究表明:内陆比较清洁地区的地面O3多年月平均变化曲线为单峰型,接近正弦曲线的形状,最高值出现在4月份,最低值出现在10月份;而空气污染比较严重的地区可能会发生出现推迟一个月峰值的情况,甚至出现连续多个月份浓度均较高的情况.而位于20°N^35°N的洋面以及海岸线上的站点均在夏季出现全年最低值.对于4个季节的平均日变化而言,清洁地区的日变化很小,曲线比较平直;而污染比较严重的区域则日变化明显,曲线弯曲幅度大,其中夏天的日变化差别最明显.为进一步分析地面O3含量的长期变化,我们还运用小波分析的方法,分析了各站点地面O3含量的变化周期,发现高纬度区域的地面O3表现出明显的准11年的周期,准2年周期振荡较弱.而其他纬度相对较低的区域和洋面上的站点则未看出有明显的准11年周期,表现出的是较明显的准2年周期振荡.

Surface ozone data of Mauna Loa and the other 14 monitoring sites of altitude lower than 1 000 m in the northern hemisphere were used to give a joint discussion for the distribution and variation features of surface 03. The data, based on ground observation, were collected, processed, and distributed by WDCGG（World Data Centre for Greenhouse Gases） in GAW（Global Atmosphere Watch）. The monthly mean and hourly data of surface ozone in these 15 sites were analyzed to sum up the difference of surface ozone annual and seasonal variations in different areas of the northern hemisphere. The results show that the monthly mean of surface O3 is like a sinusoid curve with one peak in April and one trough in October in areas with relatively clean air while the peak might be delayed for a month or the content might be high for several months in late spring and summer in areas where the air is relatively heavily polluted. And the minimum of surface ozone appears in summer for the sites of latitude between 20°N-35°N in the oceans and along the coasts. As to the mean diurnal cyele of the four seasons of 1995, the clean area does not show strong diurnal variability of surface ozone with a relatively straight line, while in the polluted area the diurnal variability is obvious especially in summer with the maximum occurring at about 3 p.m. and the minimum before sunrise. CWT（continued wavelet transform） was used to analyze the period of surface O3 of the sites, and it was found that in areas A,B and C in the higher latitudes, the most obvious period is quasi-eleven years while in the other areas and sites which are in the lower latitudes and in the oceans, the most notifiable period is quasi-biennial.