Untersuchung organischer Spurengase in der Troposphäre : globale Verteilungen, jahreszeitliche Variationen und langfristige Trends
In this study the spatial and temporal variations of the mixing ratios of organic trace gases in the lower troposphere were investigated . Air samples were collected in stainless steel canisters and analyzed for their contents of carbon dioxide, carbon monoxide, methane, nonmethane hydrocarbons and...
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| Format: | Book |
| Language: | English |
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Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2000
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| Online Access: | https://juser.fz-juelich.de/record/62329 https://juser.fz-juelich.de/search?p=id:%22PreJuSER-62329%22 |
| Summary: | In this study the spatial and temporal variations of the mixing ratios of organic trace gases in the lower troposphere were investigated . Air samples were collected in stainless steel canisters and analyzed for their contents of carbon dioxide, carbon monoxide, methane, nonmethane hydrocarbons and halocarbons. Characterizations of the used gas chromatographic systems and the resuits of international intercomparison experiments showed that the analytical methods are suitable for the measurement of organic trace gases at Iow concentration levels. The latitudinal distribution of trace gases in the boundary layer over the Atlantic was measured during the cruise of the German research vessel `Polarstern' as part of the ALBATROSS campaign (October/November 1996) . The measurements covered a latitude range between 67°N and 45°S . In this work the distribution of some halogenated hydrocarbons in marine air was measured for the First time . Highest mixing ratios of hydrocarbons and several anthropogenic halocarbons (CH2C1-,, CHCL, 1,2-C 2H4C12 , C7HC13, C2CL und CH3Br) were observed in the Northern Hemisphere between 42°N to 67°N latitude. The mixing ratios of 1,1-dichloroethene, 1,1,1-trichloroethane, dibromomethane, tribromomethane and iodomethane showed a rather uniform distribution in both hemispheres . The observed mixing ratios of methylchloride and tetrachloromethane showed Iow maxima near the equator. The seasonal variations of the mixing ratios of organic trace gases were measured in whole air samples collected in Alert (Canadian Arctic) over a time period of 7 years between January 1989 and July 1996 . The resuits allowed to estimate lang term trends of mixing ratios for a number of compounds . The mixing ratios of most hydrocarbons decreased between 2.2 to 14 .4 % per year. Except tetrachloroethene, for other halocarbons (CH3CI, CH-C12 and C,HCL), no significant trends of the Fnixing ratios were found. Tetrachloroethene showed an annual decrease of 8 .3 % per year. The observed mixing ratios of the trace ... |
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