中文摘要：

以东亚酸沉降监测网近地面O3资料,结合NCEP/NCAR的全球再分析风场、NOAA总云量及全球降水气候项目降水资料,分析2000～2007年东亚西太平洋地区近地层O3的区域和季节变化,重点分析不同站点O3月均浓度最大值时间差异的原因。结果表明,东亚以及大部分北半球中纬度清洁背景地区,近地层O3春季最高、夏季最低是广泛存在的现象。东亚夏季风的推进过程造成不同地区春季O3月均最大值出现的时间略有不同,Ogasawara和Hedo站O3浓度在3月达最大值,而Rishiri、Happo、Oki和Cheju站在4、5月达最大值。2007年副热带高压西进较晚且推进过程受阻导致Happo站2007年春季O3浓度高于气候平均值,Cheju地区2007年5月O3浓度达最大;2004年东亚夏季风爆发较早导致Hedo站2004年春季O3浓度明显低于平均值。

英文摘要：

The regional and seasonal variations of surface 03 over East Asia from 2002 to 2007 and the reason that the maximum of the 03 monthly mean values occurred at different time at different sites are analysed by using the da- ta of Acid Deposition Monitoring Network in East Asia, NCEP/NCAR, NOAA, and Global Precipiation Climatol- ogy Project. The results showed that the highest value occurred in spring and the lowest occurred in summer over East Asia and most midlatitude clean background areas in the Northern Hemisphere. Because of the East Asian monsoon advancement process the time when the monthly mean value in spring reaches the maximum are slightly different at different sites. AT Ogasawara and Hedo, they reached the highest values in March, while at Rishiri, Happo, Oki, and Cheju, they reached the highest values in April or May. This is mainly because of the push of East Asia summer monsoon. The O3 concentration is higher than the climate mean in the spring of 2007. This is mainly because of the delay of subtropical high establishing and the block of the pushing. In 2007, the O3 concentra- tion reached the maximum in May at Cheju. The O3 concentration in the spring 2004 at Hedo was significantly lower than average because of the earlier establishing of East Asia summer monsoon.