:采用自然升温方式,利用OTCs系统对青藏高原沼泽草甸生态系统分别进行3～5℃(OTC-80)和1～2℃(OTC-40)升温处理,研究环境因子对气温升高的响应及其与近地表CO_2体积分数的关系.结果表明:在日平均气温分别增高4.05,2.13℃的条件下,5 cm土壤温度平均上升3.67,1.65℃,而0～5 cm土壤含水量则分别下降7.9%,2.1%;系统内近地表CO_2体积分数比对照点的分别提高29.3,9.8muL/L.气温升高将促使青藏高原气候进一步向暖干化发展,碳库流失加剧,对全球气候变暖起正反馈作用.敏感性分析表明:5 cm土壤温度是影响OTC-80系统内和对照点近地表CO_2体积分数变化的最敏感因子,0～5 am土壤水分是影响OTG-40系统内近地表CO_2体积分数变化的最敏感因子.

The responses of environmental factors to long-term experimental warming and their relationships with the near-surface air CO_2 concentration in the swamp meadow areas on the Qinghai-Tibetan Plateau were studied using OTCs systems with 3～5℃ (OTC-80) and 1～2℃ (OTC-40) elevated respectively. The results show that under the conditions in which the daily average air temperatures were 4.05 ℃ and 2.13℃ higher in the OTC-80 and OTC-40 chambers than those at the control points, respectively, the soil temperatures at the 5 cm depth in the OTC-80 and OTC-40 chambers were respectively 3.67 ℃and 1.65 ℃ higher than those at the control points. However, the soil moistures at the 0～5 cm depth in the OTC-80 and OTC-40 chambers were 7.9% and 2.1% lower than those at the control points, respectively, and in the whole observation period, the CO_2 concentrations in the OTC-80 chambers were averagely 29.3 muL/L higher than those at the control points and 9.8 muL/L higher in the OTC-40 chambers than those at the control points. Air temperature rising led the climate warming and drying, and accelerated the soil carbon loss in the Qinghai-Tibetan Plateau, which plays a role of positive feedback to the global warming. Sensitivity analysis showed that air temperature, soil temperature and moisture at the 5 cm depth were the major environmental factors affecting the changes of the near-surface CO_2 concentrations, of which the 5 cm soil temperature was the most sensitive factor for the CO_2 concentrations change in the OTC-80 chambers and at the control points, and, relatively, 0～5 cm soil moisture was the most sensitive factor for those in the OTC-40 chambers.