摘要
用涡度相关法对亚热带红壤丘陵区人工针叶林的二氧化碳、水、热通量进行了观测,重点分析了23m、39m两层高度的观测结果,同时把观测期分为春季和冬季两个不同时间段作了对比。结果表明,不管冬季还是春季,39m高度所测的总通量值和夜间通量值都要小于23m的观测值,这种通量差别表明:23m高度的观测结果更接近当地生态系统与大气之间的通量交换值,在此种生态类型条件下用涡度相关法测碳通量时,在23m、39m两层高度之间仍然存在大气平流现象;该试验区植被在冬季仍然可以进行光合作用,而且光合作用所吸收的CO2大于呼吸作用所排放的CO2,因此该种生态系统在冬季仍表现为碳汇;春季的碳通量值为冬季的2倍以上。对不同季节内两层高度通量值的相关性也作了分析,结果表明冬季发生在23m和39m两层高度之间的大气平流量占总通量的比率要大于春季。
The covariance measurements of carbon dioxide, water and heat fluxes was carried out in Qian yanzhou station, CAS, at the different heights of 23m and 39m, respectively. Therefore, one set of data in one year for carbon dioxide, water and heat fluxes was obtained and the results at 23m and at 39m within winter and spring period were reported. The results showed that diurnal variation of carbon dioxide, water and heat fluxes at 23m and at 39m in winter and in spring had a similar changing tendency. During daytime, the ecosystem absorbed heat and H_2O vapor, but emitted CO_2 in this area. However, it was adversely during nighttime. The ranges of carbon dioxide, water and heat fluxes in winter and in spring were -1.5mg/(m^2s)～0.5mg/(m^2s), -0.02g/(m^2s)～0.08g/(m^2s), -50w/m^2～250w/m^2 and -2.0mg/(m^2s)～1.0mg/(m^2s), -0.025g/(m^2s)～0.20g/(m^2s), -50w/m^2～300w/m^2, respectively. The whole day and nighttime CO_2 fluxes at two heights in spring were all significant higher than those of winter, which indicated that in spring the photosynthesis and respiration of the vegetation in this area were intensive. In addition, it was not only in winter but also in spring, the daily flux and nighttime flux at 23m were larger than those of 39m, which indicated that there were advection and divergence fluxes between the two heights due to the heterogeneous and hilly topography in this area, therefore the measurement results at 23m were more closer to the exactly field exchange value. The vegetation was still processing photosynthesis in winter in this area. Furthermore the quantity of assimilated carbon dioxide through photosynthesis exceeded the emission through respiration, so the ecosystem in this area appeared a carbon sink even in winter. At the same time a correlation of the measurement results at two different heights in two seasons were provided, the measurement results at two heights had less difference in winter than in spring due to the less advection flow in winter.
出处
《资源科学》
CSSCI
CSCD
北大核心
2004年第3期96-104,共9页
Resources Science
基金
中国科学院知识创新工程重大项目子专题"中亚热带丘陵山地人工林生态系统碳通量观测研究"(编号:KZCX1 SW 01 01A2)
中国科学院地理科学与资源研究所知识创新工程主干科学计划专题"红壤丘陵区人工林生态系统碳通量的观测与模型研究"(编号:CX10G E01 03 05)。
