HR: 1330h
AN: A52C-0821    [PDF]
TI: Measurement of Atmospheric Carbon Dioxide on Tower in Berezorechka, West Siberian Forest Region
AU: * Watai, T
EM: watai.tomonori@nies.go.jp
AF: Global Environmental Forum, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Machida, T
EM: tmachida@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Shimoyama, K
EM: shimoyama.kou@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Krasnov, O
EM: krasnov@iao.ru
AF: Institute of Atmospheric Optics SB RAS, Akademicheskii av.1, Tomsk, 634055 Russian Federation
AU: Yamamoto, M
EM: yamamoto.masanori@nies.go.jp
AF: Global Environmental Forum, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Inoue, G
EM: inouegen@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AB: Atmospheric CO2 concentration is observed in the lower troposphere over the west Siberian forest region around Berezorechka village (56.17N, 84.33E) since October 2001 to reveal CO2 variation in and over planetary boundary layer (PBL). Ground based measurement is conducted using a tower with its height about 90m, and lower tropospheric observation is done between 100-2000m height every 1-3 weeks using aircraft. The tall tower stood in forest with its canopy height of 10-15m and four air intakes are attached at about 80, 40, 20 and 5 m height of the tower. The pressurized air by a diaphragm pump is dehumidified and introduced into analyzer (Li-Cor : LI-7000) at constant flow rate (35 ml min-1). Sample air at each height is introduced into analyzer for six minutes and last one minute signal is used for calculation. The CO2 concentration is determined against three CO2-in-air standard gases based on the National Institute for Environmental Studies (NIES) standard gas scale. The feature of this system is to employ on-site compressed air as both reference gas for analyzer and sub-standard gas. Ambient air compressed into 48L cylinder up to about 0.5MPa is kept for about ten days and then used for the reference and sub-standard gas. Analysis of all four heights sample air and sub-standard gas is done every 30 minutes except twice a day when three standard gases are analyzed. Total precision is estimated to be 0.3ppm. The observed CO2 concentration generally shows diurnal variation with low value in daytime, increase from evening till early morning and decrease till evening. The amplitude of diurnal variation is large in summer and small in late winter. The CO2 diurnal variation is different day by day even in a same season and well correlated with temperature profile variation. Clear inversion layer is observed in calm and/or clear sky night, and the concentration increases from ground surface to higher height accompanied with inversion layer growth. Larger vertical CO2 difference in July than in February at night suggests that CO2 release from land biosphere is also larger in July than in February. On a day when inversion layer is not observed, CO2 variation at each height is similar to each other, and its difference is in 5ppmv. These CO2 temporal and vertical variations are resulted from covariance of biospheric activity, photosynthesis and variation of inversion layer.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions
DE: 0365 Troposphere--composition and chemistry
DE: 3307 Boundary layer processes
DE: 4806 Carbon cycling
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting