摘要
高寒草甸是青藏高原广泛分布的植被类型之一,面积约120万km2,地处青藏高原腹地的当雄草原站即位于该类植被的典型分布区.以2003年8～10月中旬在该站用涡度相关法连续观测的CO2通量数据资料为基础,分析了高寒草甸生态系统8～10月份净二氧化碳交换量(NEE)的日变化规律,及其与光合有效辐射、降水、温度等环境因子之间的关系.结果表明,8～10月份的日均NEE有明显的日变化,表现为单峰型,通常在地方时11:00～12:00左右达到碳吸收的最大值,平均为-0.2680 mg CO2/(m2·s)(-6.0800μmol CO2/(m2·s)).白天的NEE与光合有效辐射之间符合很好的直角双曲线关系,表观量子产额平均为0.0203μmol CO2/μmol PAR,表观最大光合速率平均为 9.7411 μmolCO2/(m2·s).夜晚的NEE与5cm地温有很好的指数函数关系.
The alpine meadow is widely distributed on the Tibetan Plateau, covering about 1.2 million km^2. At the Damxung Grassland Station, located in the hinterland of the plateau 15 the place covered with this typical vegetation. The continuous carbon flux （from August to middle October, 2003） of the alpine meadow was measured using the open-path eddy covariance systems in order to analyze the diurnal variation patterns of net ecosystem carbon dioxide exchange （NEE） and its relationship with environmental factors, such as photosynthetically active radiation （PAR）, precipitation and temperature. Obvious diurnal variation patterns of NEE with single peaked carbon assimilation were observed at 11：00 - 12：00 （local time） with an average of -0. 2680 mg CO2/（m^2 · s） （-6. 08μmol CO2/（m^2 · s））. During the daytime, NEE fitted fairly well with PAR in a rectangular hyperbola function, with apparent quantum yield of 0. 0203μmol CO2/μmol PAR and maximum ecosystem assimilation of 9. 7411 μmol CO2/（m^2·s）. In the nighttime, NEE was fairly exponentially related with the soil temperature at 5cm below ground.
出处
《生态学报》
CAS
CSCD
北大核心
2005年第8期1948-1952,共5页
Acta Ecologica Sinica
基金
国家973计划资助项目(2002CB412501)~~
关键词
青藏高原
高寒草甸
涡度相关法
二氧化碳通量
环境因子
Tibetan Plateau
alpine meadow
eddy covariance
carbon dioxide flux
environmental factors
