中文摘要：

利用涡度相关技术对青藏高原高寒灌丛CO2通量进行连续观测，并以2003年7、8月份为例，对高寒灌丛暖季CO2通量变化模式及其主要气候影响因子进行了分析．结果表明，7、8月青藏高原高寒灌丛日平均净生态系统CO2交换（NEE）分别为7．17,-7．26g/（m^2·d）；最高日NEE分别为-11．00，-12．09g/（m^2·d）．暖季高寒灌丛生态系统NEE日变化波动极为明显，8：00-19：00为CO2净吸收阶段，峰值一般出现在12：00左右，最大值为1．72g/（m^2·h））（7月份）、-1．63g/（m^2·h）（8月份）．19：00-次日8：00为CO2净释放，最大值为O．69g/（m^2·h）（7月份）、0．86g/（m^2·h）（8月份）．在主要气候因子中，光合有效辐射（PAR）与NEE变化呈显著正相关，但PAR达到1000μmol／（m^2·s）以后，随着PAR进一步升高，NEE有下降趋势．就温度而言，白昼（7：00-20：00）NEE变化与温度无显著关联，而夜间（21：00～次日6：00）温度与NEE变化呈显著正相关．

英文摘要：

Utilizing the eddy covariance technique, CO2 fluxes in alpine shrub of the Qinghai-Tibet Plateau was observed continuously; and taking July and August in 2003 as example, the change model of CO2 fluxes in warm season of alpine shrub and its main climate influence factors were analyzed. The average daily net ecosystem CO2 exchange （NEE） of alpine shrub of Qinghai-Tibet Plateau in July and August were -7.17, -7.26 g/（m^2·d） respectively with the highest daily NEE of-ll.00, -12.09 g/（m^2·d）. The daily change fluctuation of warm season alpine shrub ecosystem NEE was very obvious. 08：00-19：00 hours was the net absorption stage, the net absorption peak value appearing generally about 12：00 hour with the greatest value of-1.72 g/（m^2·h） （July） and -1.63 g/（m^2·h） （August）, respectively. The CO2 net release was in 19：00-8：00 next day, with the greatest values of 0.69 g/（m^2·h）（July） and 0.86 g/（m^2·h） （August）. In main climate factors, the photosynthetically active radiation（PAR） appeared remarked positive relation with NEE change, but after PAR reached 1000 μmol/（m^2·s）, NEE tended to declined with farther increasing of PAR. As for temperature, NEE change was not correlated markedly with the temperature in the daytime （07：00-20：00）; but in the night time （21：00-06：00 next day）, the temperature and NEE change appeared marked positive relation.