Diurnal and monthly variations of carbon dioxide flux in an alpine shrub on the Qinghai-Tibet Plateau  

作　　者：XUShixiao ZHAOXinquan LIYingnian ZHAOLiang YUGuirui SUNXiaomin CAOGuangmin 

机构地区：[1]NorthwestInstituteofPlateauBiology,ChineseAcademyofSciences,Xining810001,China [2]NorthwestInstituteofPlateauBiology,ChineseAcademyofSciences,Xining810001,China//GraduateSchoolofChineseAcademyofSciences,Beijing100136,China [3]InstituteofGeographicalSciencesandNaturalResourcesResearch,ChineseAcademyofSciences,Beijing100101,China

出　　处：《Chinese Science Bulletin》2005年第6期539-543,共5页

基　　金：This work was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant Nos.KZCX 1-SW-01-01A5 and KZCX1-09-01);State Key Basic Research Plan of China(Grant No.2002CB412501);Priority Areas Program of Northwest Institute of Plateau Biology(Grant No.CXLY-2002-l).

摘　　要：Continuous CO2 flux observation with eddy covariance method conducted in the alpine shrub on the Qinghai-Tibet Plateau indicates that there are distinct diur- nal and monthly variations for CO2 fluxes in the alpine shrub on the plateau. As for diurnal variation, with net CO2 influx from 08:00 to 19:00 and net CO2 efflux from 20:00 to 07:00, peak CO2 flux during warm season (July) appears around 12:00 (?1.19 g CO2·m?2·h?1); there is no obvious horary fluctuation for CO2 flux during cold season (January), and horary CO2 flux during most hours in a day is close to zero except for a small amount of net efflux (about 0.11 g CO2·m?2·h?1) from 11:00—17:00. As for monthly varia- tion, with net CO2 influx from June to September and net CO2 efflux from January to May and October to December, the peak monthly CO2 influx and CO2 efflux appear in Au- gust and April, respectively. The total net CO2 influx from June to September and total net CO2 efflux from February to May and October to December in the alpine shrub on the Qinghai-Tibet Plateau are estimated to be 673 and 446 g CO2·m?2. Results show that the alpine shrub on the Qing- hai-Tibet Plateau is remarkable carbon dioxide sink under no grazing conditions and the total yearly CO2 influx is esti- mated to be 227 g CO2·m?2.Continuous CO_2 flux observation with eddy covariance method conducted in thealpine shrub on the Qinghai-Tibet Plateau indicates that there are distinct diurnal and monthlyvariations for CO_2 fluxes in the alpine shrub on the plateau. As for diurnal variation, with netCO_2 influx from 08:00 to 19:00 and net CO_2 efflux from 20:00 to 07:00, peak CO_2 flux during warmseason (July) appears around 12:00 (-1.19 g CO_2 centre dot m^(-2) centre dot IT1); there is noobvious horary fluctuation for CO_2 flux during cold season (January), and horary CO_2 flux duringmost hours in a day is close to zero except for a small amount of net efflux (about 0.11 g CO_2centre dot m^(-2) centre dot h^(-1)) from 11:00-17:00. As for monthly variation, with net CO_2influx from June to September and net CO_2 efflux from January to May and October to December, thepeak monthly CO_2 influx and CO_2 efflux appear in August and April, respectively. The total netCO_2 influx from June to September and total net CO_2 efflux from February to May and October toDecember in the alpine shrub on the Qinghai-Tibet Plateau are estimated to be 673 and 446 g CO_2centre dot m^(-2). Results show that the alpine shrub on the Qinghai-Tibet Plateau is remarkablecarbon dioxide sink under no grazing conditions and the total yearly CO_2 influx is estimated to be227 g CO_2 centre dot m^(-2).

关 键 词：二氧化碳 流量 青藏高原 高山灌木丛 协方差 

分 类 号：S718.551.2[农业科学—林学] Q948.158[生物学—植物学]