温度对青藏高原高寒灌丛CO_2通量日变化的影响

The Correlation between CO_2 Flux and Temperature of the Alpine Shrub Meadow on the Tibetan Plateau

应用涡度相关技术连续监测的CO2通量及温度数据（2003年1月1日至2004年12月31日）,分析了青藏高原高寒灌丛净生态系统CO2交换（NEE）日变化与温度之间的关系.结果表明：1）在暖季夜间（21：00至次日06：00时）温度与NEE变化呈显著正相关关联,而白昼（07：00~20：00时）NEE变化与温度无显著关联;2）在冷季不论夜间还是白昼,NEE变化均与温度密切相关,温度是决定冷季高寒灌丛生态系统CO2交换的主要因素.在全球气候变暖背景下,青藏高原气候变化呈现出冬季增温率明显高于春、夏季特征,未来气候变暖导致的增温效应可能会加速青藏高原高寒灌丛生态系统CO2排放,使其作为碳汇的能力而减弱.

Based on the continuous CO2 flux observation with eddy eovariance method conducted in the alpine shrub on the Tibetan Plateau from 1 January to 31 December in 2003 and 2004, the rela- tionship between CO2 flux and temperature is analyzed. The following results are obtained： 1） during the warm season, net ecosystem CO2 exchange （NEE） is significantly correlated to the tempera- ture in night （21：00~06：00）, but there is no significant correlation in daytime （07：00~20：00） ; 2）as for cold season, NEE has significant correlation with temperature both in daytime and night. Temperature increasing ratio in winter is higher than that in spring or summer over the Tibetan Plateau under the background of global warming. Consequently, owing to the future warming of climate, CO2 efflux over the ecosystem will speed up, and then, the carbon converge capability of alpine shrub meadow on the Tibetan Plateau will be weaken.