Characterizing CO 2 fluxes for growing and non-growing seasons in a shrub ecosystem on the Qinghai-Tibet Plateau
Characterizing CO 2 fluxes for growing and non-growing seasons in a shrub ecosystem on the Qinghai-Tibet Plateau
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DOI：
10.1360/05zd0013
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发表时间：
2005-06
影响因子：
5.7
通讯作者：
Xu Shixiao;Zhao Xinquan;Fu Yuling;Zhao Liang;Li Yingnian;Cao Guang-min;Gu Song;W. Qinxue;Mingyuan Du
中科院分区：
文献类型：
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作者：
Xu Shixiao;Zhao Xinquan;Fu Yuling;Zhao Liang;Li Yingnian;Cao Guang-min;Gu Song;W. Qinxue;Mingyuan Du
为评估青藏高原灌丛生态系统的碳收支，采用开放路径涡度相关系统对青藏高原高寒灌丛生态系统生长季和非生长季的CO2通量进行了测量。两季CO2通量变化规律不同.在5 ~ 9月的生长季中，08：00 ~ 19：00（北京时间）为CO2净吸收期，19：00 ~ 08：00为CO2净排放期。6、7、8、9月的最大CO2吸收量分别为0.71、1.19、1.46和0.67gCO2m-2 h-1。CO2通量日变化与光合光子通量密度的相关性高于温度。CO2净流入量最大值出现在8月份，为247 gCO 2 m-2.生长季生态系统总CO2吸收量为583 gCO 2 m-2。在1 ~ 4月和10 ~ 12月的非生长季，CO2通量波动较小，4月CO2净排放量最大，为0.30gCO2 m-2 h-1。CO2日通量在一天中的大部分时间接近于零，但在11：00 ~ 18：00有少量的CO2净流出。在非生长季，CO2日通量与温度日变化呈显著正相关。CO2月净排放量最大值出现在4月份，为105 gCO 2 m-2.整个非生长季的CO2净排放量为356 gCO 2 m-2。
To assess carbon budget for shrub ecosystems on the Qinghai-Tibet Plateau, CO 2 flux was measured with an open-path eddy covariance system for an alpine shrub ecosystem during growing and non-growing seasons. CO 2 flux dynamics was distinct between the two seasons. During the growing season from May to September, the ecosystem exhibited net CO 2 uptake from 08:00 to 19:00 (Beijing Standard Time), but net CO 2 emission from 19:00 to 08:00. Maximum CO 2 uptake appeared around 12:00 with values of 0.71, 1.19, 1.46 and 0.67 g CO 2 m -2 h -1 for June, July, August and September, respectively. Diurnal fluctuation of CO 2 flux showed higher correlation with photosynthetic photon flux density than temperature. The maximum net CO 2 influx occurred in August with a value of 247 g CO 2 m -2 . The total CO 2 uptake by the ecosystem was up to 583 g CO 2 m -2 for the growing season. During the non-growing season from January to April and from October to December, CO 2 flux showed small fluctuation with the largest net CO 2 efflux of 0.30 g CO 2 m -2 h -1 in April. The diurnal CO 2 flux was close to zero during most time of the day, but showed a small net CO 2 efflux from 11:00 to 18:00. Diurnal CO 2 flux, is significantly correlated to diurnal temperature in the non-growing season. The maximum monthly net CO 2 efflux appeared in April, with a value of 105 g CO 2 m -2 . The total net CO 2 efflux for the whole non-growing season was 356 g CO 2 m -2 .