中文摘要：

高寒草甸是青藏高原地区的主要植被类型，目前对其温室气体研究多集中于生长季。本文利用静态箱-气相色谱法，对非生长季高寒草甸温室气体排放特征及其与主要环境因子的关系进行了研究。结果表明：非生长季高寒草甸表现为CO2和N2O的源、CH4的汇。其中非生长季CO2通量平均值为89.33 mg.m-2.h-1，累积排放通量为280.01g.m-2；CH4通量平均值为-11.35 μg.m-2.h-1，累积吸收通量为124.74 mg.m-2；N2O通量平均值为8.02μg.m-2.h-1，累积排放通量为39.51 mg.m-2。非生长季CO2、CH4和N2O累积排放通量分别占全年的13.33%、53.47%和62.67%。冻融期（2012年4月）CH4累积吸收通量较小，只占非生长季的4.5%；而CO2和N2O累积排放通量较大，分别占非生长季的25.8%和20.8%。非生长季CO2通量与温度（气温、5和10 cm土壤温度）和5 cm土壤湿度均存在显著正相关关系，而CH4和N2O通量仅与5 cm土壤湿度存在显著正相关。研究表明，虽然冻融期CH4累积吸收通量在非生长季累积量中比重较小，但非生长季CH4和N2O累积排放量却占全年累积排放量的1/2以上，在温室气体累积通量评估中不容-忽视。

英文摘要：

Alpine meadow is widely distributed on the Tibetan Plateau. The studies on the greenhouse gases （GHGs） flux in the alpine meadow are mostly carried out during growing season, but scarcely quantified during nongrowing season. By using static chamber technique and gas chromatography, this paper studied the characteristics of CO2, CH4, and N2O fluxes in this alpine meadow during nongrowing season. The mean fluxes of CO2, CH4, and N2O were 89.33 mg＆middot;m-2＆middot;h-1, -11.35 μg＆middot;m-2＆middot;h-1, and 8.02 ＆mu;g＆middot;m-2＆middot;h-1, and the cumulative fluxes were 280.01 g＆middot;m-2, -124.74 mg＆middot;m-2, and 39.51 mg＆middot;m-2, respectively. Therefore, this alpine meadow was performed as the sources of CO2 and N2O and the sink of CH4 during nongrowing season. The cumulative CH4, CO2 and N2O fluxes during nongrowing season contributed 13.33%, 53.47% and 62.67% of the total in a whole year. During freezethawing period （April, 2012）, cumulative CH4 flux was smaller, only contributing 4.5% of the total during non-growing season, whereas the cumulative CO2 and N2O fluxes were larger, contributing 25.8% and 20.8%, respectively. The CO2 flux during nongrowing season had significant positive correlations with air temperature, soil temperature at the depths of 5 cm and 10 cm, and soil moisture at depth 5 cm. Our results showed that though the cumulative CH4 flux during freezethawing period only occupied a smaller part of that during nongrowing season, the cumulative CH4 and N2O fluxes during nongrowing season contributed more than 50% of the total in a whole year, which should not be neglected in the estimation of the GHGs fluxes and their global warming potential in the alpine meadow on the Tibetan Plateau.