中文摘要：

利用基于光腔衰荡光谱（CavityRingDownSpectroscopy，CRDS）技术自组装的大气CO2在线观测系统，于2010年9月—2011年8月在云南香格里拉大气本底站对大气CO2进行了初步观测．该站春、夏、秋、冬季C02平均本底浓度分别为394．78×10-6（物质的量之比，下同）、386．82×10-6、386．46×10-6和390．74×10-6．全年浓度在4—5月最高，7月份最低，全年月均值振幅约12．22×10-6．四季浓度日平均高值出现在上午7：00左右，最低值出现在14：00—17：00．日变化振幅在冬季最小，夏季最大，分别为1．51×10-6和21．82×10-6．四季西南来向的地面风对CO2浓度均有明显的降低作用．通过四季每日整点后向轨迹聚类计算，结合浓度资料分析发现，该站春、夏、秋季来自于西南方向的气团降低了观测的CO2浓度，而在冬季未起到明显的降低作用，主要因该站局地植被生态系统排放减少所致．

英文摘要：

Atmospheric CO2 concentration was continuously measured at Xianggelila background station by Cavity Ring Down Spectroscopy system from September 2010 to August 2011. The average background concentrations during spring, summer, autumn and winter were 394.78 × 10-6（ mole ratio, the same below）, 386.82 × 10 -6, 386.46× 10 -6 and 390.74 × 10 -6, respectively. The monthly average variation reached a maximum in April-May period and a minimum in July with the amplitude to be about 12.22×10-6. The hourly average CO2 concentration exhibited evident diurnal variation with maximal values around 7 ： 00 and minimal around 14 ： 00-17 ： 00 during all the seasons. The daily variation amplitude was the lowest in the winter （ 1.51 ×10-6） and the highest in the summer （21.82 × 10-6）. Evident decrease of CO2 concentration was usually observed when the surface wind came from the west to south sector. Combined with the observed CO2 concentrations, cluster analysis of 3 day backward trajectories ending at full hour suggested that the air mass from south-west obviously reduced the observed CO2 concentrations during spring, summer and autumn. However, in the winter, the decrease was not apparent because of the lower emissions from the local vegetation than the other seasons.