HR: 1340h
AN: B33B-1028    [Abstracts]
TI: Emission of Methyl halides from Japanese rice paddy fields.
AU: * Komori, D
EM: d-small-forest@depe.titech.ac.jp
AF: Tokyo Institute of Technology, 4259-G5-12 Nagatsuta, Midori-ku, Yokohama, JPN 226-8502 Japan
AU: Sudo, S
EM: ssudo@niaes.affrc.go.jp
AF: National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, JPN 3058604
AU: Akiyama, H
EM: ahiroko@niaes.affrc.go.jp
AF: National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, JPN 3058604
AU: Nishimura, S
EM: ssnn@niaes.affrc.go.jp
AF: National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, JPN 3058604
AU: Yagi, K
EM: kyagi@affrc.go.jp
AF: National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, JPN 3058604
AU: Hayashi, K
EM: kentaroh@affrc.go.jp
AF: National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, JPN 3058604
AU: Tanaka, Y
EM: yukaritanaka@depe.titech.ac.jp
AF: Tokyo Institute of Technology, 4259-G5-12 Nagatsuta, Midori-ku, Yokohama, JPN 226-8502 Japan
AU: Yamada, K
EM: kyamada@chemenv.titech.ac.jp
AF: Tokyo Institute of Technology, 4259-G5-12 Nagatsuta, Midori-ku, Yokohama, JPN 226-8502 Japan
AU: Toyoda, S
EM: stoyoda@chemenv.titech.ac.jp
AF: Tokyo Institute of Technology, 4259-G5-12 Nagatsuta, Midori-ku, Yokohama, JPN 226-8502 Japan
AU: Koba, K
EM: kkoba@depe.titech.ac.jp
AF: Tokyo Institute of Technology, 4259-G5-12 Nagatsuta, Midori-ku, Yokohama, JPN 226-8502 Japan
AU: Yoshida, N
EM: naoyoshi@depe.titech.ac.jp
AF: Tokyo Institute of Technology, 4259-G5-12 Nagatsuta, Midori-ku, Yokohama, JPN 226-8502 Japan
AB: Rice paddy field is one of emission source of methyl halide (MeX: X = Cl, Br, I) which are concerned about stratospheric ozone depletion and enhanced aerosol formation. Although significant amounts of MeX which are estimated to be emitted from rice paddies affect to regional and global atmospheric environment, understandings and recent estimations of production and consumption mechanisms of MeX have large uncertainty with depending on environmental conditions. In this study, new flux data sets of MeX emissions from Japanese rice paddy fields were reported. The fluxes of MeX were compared with environmental data sets which included meteorological parameters (ambient air temperature, ambient MeX concentrations, humidity, solar irradiance), soil parameters (soil temperature, pH, redox potential, soil water contents) to understand the emission mechanisms of MeX. Gas fluxes of C2H4 were also measured, which indicate rice plants growth and ageing. Observations of MeX flux were conducted with using automated closed chamber sampling system in Tsukuba, Japan, during a cultivation season of rice from May 2005 to September 2005. Rice plants were cultivated under intermittent irrigation. Soil gases were collected manually by using evacuated 1L stainless canisters once a week and every 4 hours in certain day during this period. Other environmental parameters were automatically obtained every 10 minutes. Seasonal variation of gas emissions of C2H4 were observed in maximum tillering phase and heading phase. In addition, clearly diurnal flux trends of C2H4 depending on solar irradiance were observed. These results suggested rice plant was remarkably growing in these phase. Similarly, large amounts of gas emissions of MeBr and MeI were observed in the same phase. Diurnal flux trends of MeBr and MeI were associated with solar irradiance. Results were generally consistent with previous reports (Redeker et al., 2000). On the other hand, MeCl flux was increased in later periods than maximum periods of MeBr and MeI.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0400 BIOGEOSCIENCES
DE: 0428 Carbon cycling (4806)
DE: 0438 Diel, seasonal, and annual cycles (4227)
SC: Biogeosciences [B]
MN: Fall Meeting 2005