HR: 1330h
AN: A52C-0816    [PDF]
TI: Diurnal Variation in CO2 Profile in the Lower Troposphere above a West Siberian Forest
AU: * Shimoyama, K
EM: shimoyama.kou@nies.go.jp
AF: National Institute for Environmental Studies, 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: Watai, T
EM: watai.tomonori@nies.go.jp
AF: Global Environmental Forum, 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: Inoue, G
EM: inouegen@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Zeng, J
EM: zeng@nies.go.jp
AF: Global Environmental Forum, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AB: Diurnal variation of atmospheric carbon dioxide (CO2) concentration in lower troposphere (from 150 to 2000 m) was measured above Berezorechka village in west Siberia (56$\deg$;N, 85$\deg$E) over considerably homogeneous and flat forest area using aircraft. Measurements were performed every two hours from 6:00 to 20:00 on July 18, 19, 23 and 26, 2002. In the morning, nocturnal boundary layer (NBL) height was approximately 200 m and higher CO2 was observed in this layer. On July 18, convective boundary layer (CBL) height had been kept almost constant during the day around 1700 m. On July 19, the CBL height decreased from 1200 m in the morning to 800 m in the evening due to warm front passing through this region. On July 23, CBL was developed from the morning and grew to a height of 1300 m in late afternoon. On July 26, CBL was difficult to determine because CO2 within the measurement layer was largely scattered caused by advection of different air mass. In general, CO2 within the CBL was homogeneous and decreased during the daytime, which implied that CO2 uptake existed at the surface. This was clearly shown in July 23. On the contrary, increasing of CO2 was observed on July 19 and 26, due to the advection of higher CO2 air mass. CO2 within the CBL also correlated with the CO2 above the CBL through entrainment exchange. The result of 5 days back trajectory analysis showed that the higher CO2 air mass generally came from the higher altitude. The lower CO2 air mass was traced the lower altitude, which indicated that the air mass was much affected by surface CO2 uptake.
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