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 sh...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.展开更多
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).
文摘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.
