Abstract: Spatial distributions of tropospheric NO₂ over China and variations of tropospheric NO₂ for selected regions in China are studied using of satellite monitoring data (GOME and SCIAMACHY) from March 1996 to March 2008. Global Chemistry-Transport Model (MOART-2) simulation is carried out to reveal significant seasonal variations of tropospheric NO₂ over megalopolis areas in eastern China. Results show that: 1) Maximum distribution of tropospheric NO₂ lies in region of Beijing-Hebei-Tianjing, Yangtze Delta, Perl river delta. Obvious increasing trend can be seen over East China, with a yearly increasing rate of 0.9×1015cm_-2. 2) Becacuse of effective eliminating of NO₂ by OH, tropospheric NO₂ over megalopolis in East China shows significant seasonal variations: tropospheric NO₂ maximum appears in winter, and decreases sharply in summer. In background area West China where natural emissions dominates, tropospheric NO₂ shows reversed phenomenon compared to the East.

Key words: GOME, SCIAMACHY, MOZART-2, troposphere NO_2

摘要： 利用卫星观测数据(GOME和SCIAMACHY)分析了1996年3月至2008年3月中国地区对流层NO₂的分布特征和选定地区对流层NO₂的变化趋势，并结合大气化学传输模式（MOZART-2）对中国东部大城市上空对流层NO_2显著季节变化的原因进行了分析。研究发现：1）中国地区对流层NO₂高值区主要分布在京津冀地区、长江三角洲和珠江三角洲；中国东部污染地区对流层NO₂呈现显著的增长趋势，年平均增长值达到0.9×1015cm_-2。2）中国东部大城市上空对流层NO_2存在明显的季节变化，原因是OH对于对流层NO₂的有效清除机制，对流层NO₂在冬季出现高值，夏季迅速降低至一年中最低值；在以自然排放源为主的中国西部背景地区，对流层NO₂则呈现明显的夏季高冬季低的特征。

关键词: GOME, SCIAMACHY, MAZART-2, 对流层NO_2