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1、大气中的一氧化碳记录大气中的一氧化碳记录,Estevan Point,加拿大加拿大(Atmospheric carbon monoxide record from Estevan Point, Canada) 数据介绍：数据介绍： Individual measurements have been obtained from flask air samples returned to the CSIRO GASLAB. Typical sample storage times range from days to weeks for some sites (e.g. Cape Grim) to
2、 as much as 1 year for Macquarie Island and the Antarctic sites. Experiments carried out to test for changes in sample CO mixing ratio during storage have shown significant drifts in some flask types over test periods of several months to years (Cooper et al., 1999). Corrections derived from the tes
3、t results are applied to network data according to flask type. (Data from the “S160“ flasks have been rejected due to large and variable drift.) 关键词：关键词： 数据格式：数据格式： TEXT 数据详细介绍：数据详细介绍： Atmospheric carbon monoxide record from Estevan Point, CanadaAtmospheric carbon monoxide record from Estevan Point,
4、 Canada L.P. Steele, P.B. Krummel and R.L. LangenfeldsL.P. Steele, P.B. Krummel and R.L. Langenfelds Commonwealth Scientific and Industrial Research Organization (CSIRO), Atmospheric Research, Aspendale, Victoria, Australia, 3195 Period of RecordPeriod of Record July 1993 - December 2001 MethodsMeth
5、ods Individual measurements have been obtained from flask air samples returned to the CSIRO GASLAB. Typical sample storage times range from days to weeks for some sites (e.g. Cape Grim) to as much as 1 year for Macquarie Island and the Antarctic sites. Experiments carried out to test for changes in
6、sample CO mixing ratio during storage have shown significant drifts in some flask types over test periods of several months to years (Cooper et al., 1999). Corrections derived from the test results are applied to network data according to flask type. (Data from the “S160“ flasks have been rejected d
7、ue to large and variable drift.) Samples were analyzed by gas chromatography with a mercuric oxide reduction gas detector. CO reduces HgO to Hg vapour which is detected by UV absorption. One Trace Analytical gas chromatograph, labeled “RGA3-1“ (R1) was used over the length of the record. Further det
8、ails of CSIROs global sampling network, sampling procedure, and analytical techniques are provided elsewhere (Francey et al., 1996); measurement uncertainty is discussed by Langenfelds et al. (2001). Data are linked to the gravimetrically-derived scale of NOAA/CMDL (Novelli et al., 1991) using a sin
9、gle high-pressure cylinder standard with a CO-in-dry-air mole fraction of 196 ppb. This standard is one of five synthetic mixtures of CO2, CH4 and CO in zero air, in the range 30-196 ppb, that were calibrated at NOAA/CMDL between 1992 and 1994. Stability of the CSIRO scale and variations in instrume
10、nt response are monitored with 20 high-pressure cylinder standards, with lifetimes of 4-10+ years, spanning a CO mole fraction range of 20-400 ppb. More detailed calibration information is given by Langenfelds et al. (2001). A number of observed systematic influences complicate the inter-comparabili
11、ty of atmospheric CO measurements made by different laboratories. Comparison of CSIRO and NOAA flask measurements indicates a mean difference of 5.9 1.7 ppb; that is, the differences frequently exceed 10% of the measured CO concentrations at high latitudes in the Southern Hemisphere (where the lowes
12、t CO concentrations are typically found). More details and possible reasons for the differences are discussed in detail by Masarie et al. (2001). These data represent monthly means, calculated as the mean of daily values from a smooth curve fit to the data using the curve-fitting routines described
13、by Thoning et al. (1989). Estevan Point, BC, Canada Estevan Point, BC, Canada 4923 N, 12632 W, 39 m , above MSL4923 N, 12632 W, 39 m , above MSL Trends Trends An annual pattern of CO is evident, largely due to an increase in its destruction by the OH radical during the summer months. Additional infl
14、uences include spatial and seasonal differences in source strength associated with varying trajectories of arriving air at different times of the year. The annual average mixing ratio at Estevan Point for 2001 had decreased by about 12 percent of its 1994 value. An anomalous string of high monthly v
15、alues during October-December 1998, coupled with higher than normal values during the preceding summer, contributed to an anomalously high annual average mixing ratio (148 ppb) for 1998. Elevated CO mixing ratios were observed on a global scale during 1998 (see Langenfelds et al., 2002). References
16、References Cooper, L.N., L.P. Steele, R.L. Langenfelds, D.A. Spencer and M.P. Lucarelli. 1999. Atmospheric methane, carbon dioxide, hydrogen, carbon monoxide and nitrous oxide from Cape Grim flask air samples analysed by gas chromatography. Baseline Atmospheric Program (Australia) 1996, edited by J.L. Gras, N. Derek, N.W. Tindale and A.L. Dick, pp 98 - 102, Bureau of Meteorology and CSIRO Atmospheric Research, Melbourne, Australia. Francey, R.J., L.P. Steele, R.L.
