Trends of tropospheric CO, N2O and CH4 as observed at cape point, South Africa

Brunke, E.-G.; Scheel, H.E.; Seiler, W.

doi:10.1016/0960-1686(90)90013-d

Cited by 88 publications

(48 citation statements)

References 27 publications

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“…No abrupt change in rate of methane increase from 1982 to 1983 was also observed at Cape Grim in the Southern Hemisphere (Fraser et al, 1986). 1985 has fallen from the preceding several years (Steele et al, 1987;Blake and Rowland, 1988;Brunke et al, 1990). From these results, it is ap parent that the rate of methane increase in the troposphere exhibited slight interannual fluctua tions for the past decade, although the cause for the fluctuation can not be deduced from the limited data at present stage.…”

Section: Temporal Increasesmentioning

confidence: 55%

“…Three research groups began systematic recording of methane concen trations in clean air in 1978 (Blake and Rowland, 1986;Fraser et al, 1986;Khalil and Rasmussen, 1986). Subsequently, the other two groups also started to take frequent measurements at the background stations from 1982 (Steele et al, 1987;Brunke et al, 1990). These studies indicate that levels of atmospheric methane are rapidly in creasing in both hemispheres.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Atmospheric methane over the western Pacific and the Antarctic Ocean from 1978 to 1986.

Matsueda¹,

Inoue²,

Sugimura³

1992

Geochem. J.

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Methane concentrations were determined for air samples collected over the western Pacific and the Antarctic Ocean in the years from 1978 to 1986. The latitudinal distribution from 35°N to 65°S revealed a decrease in methane concentration towards south, with two sharp gradients around 20°N and the inter tropical convergence zone (ITCZ). The methane concentrations south of ITCZ were much lower than those in the Northern Hemisphere. The average concentrations of methane in samples collected over the western North Pacific (9°N-24°N) indicate an almost linear increase from 1978 to 1986 with no signifi cant fluctuation of the annual rate of methane increase. The average rate of the increase from 1978 to 1986 was calculated to be 17 ± 2 ppb / yr over the western North Pacific, and that over the Antarctic Ocean was estimated to be 16-17 ppb/yr from 1978 to 1984.

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Section: Temporal Increasesmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Atmospheric methane over the western Pacific and the Antarctic Ocean from 1978 to 1986.

Matsueda¹,

Inoue²,

Sugimura³

1992

Geochem. J.

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“…Maintenance of CO gas standards is often plagued by drift of the CO mixing ratios in high-pressure gas cylinders, particularly at ppbv levels (Novelli et al, 1991(Novelli et al, , 1994. Although the drift rate of CO mixing ratios is only a few ppbv per year (compared to the few tens to hundreds of ppbv CO at which the standards are prepared), the drift substantially affects derivation of long-term trends and interannual variability of CO (Zander et al, 1989;Brunke et al, 1990;Novelli et al, 2003;Zellweger et al, 2009). Furthermore, the drift substantially affects the calibration scales maintained for long-term atmospheric monitoring programs.…”

mentioning

confidence: 99%

Onboard measurement system of atmospheric carbon monoxide in the Pacific by voluntary observing ships

et al. 2011

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Abstract. Long-term monitoring of carbon monoxide (CO) mixing ratios in the atmosphere over the Pacific Ocean is being carried out on commercial cargo vessels participating in the National Institute for Environmental Studies Voluntary Observing Ships program. The program provides a regular platform for measurement of atmospheric CO along four cruise routes: from Japan to Oceania, the United States, Canada, and Southeast Asia. Flask samples are collected during every cruise for subsequent analysis in the laboratory, and in 2005, continuous shipboard CO measurements were initiated on three of the routes. Here, we describe the system we developed for onboard measurement of CO mixing ratios with a commercially available gas filter correlation CO analyzer. The fully automated system measures CO in ambient air, and the detector sensitivity and background signals are calibrated by referencing the measurements to a COin-air standard gas (∼1 ppmv) and to CO-free air scrubbed with a catalyst, respectively. We examined the artificial production of CO in the high-pressure working gas standards during storage by referencing the measurements to CO standard gases maintained as our primary scale before and after use on the ships. The onboard performance of the continuous CO measurement system was evaluated by comparing its data with data from laboratory analyses of flask samples using gas chromatography with a reduction gas detector. The reasonably good consistency between the two independent measurement methods demonstrated the good performance of both methods over the course of 3-5 years. The continuous measurement system was more useful than the flask sampling method for regionally polluted air masses, which were often encountered on Southeast Asian cruises.

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“…There is a strong hemispheric gradient [Novelli et al, 1992] and seasonal cycle in atmospheric CO concentrations [Brunke et al 1990;Novelli et al, 1992]. The CO source strength is stronger in the northern hemisphere (NH) than in the southern hemisphere (SH), and the atmospheric lifetime of a few months for CO is less than the hemispheric mixing time of a year, leading to higher concentrations in the Nit, The seasonal variation is in excess of 100 ppbv at Barrow (71.32 ø N), between 40-60 ppbv at 20øN [Novelli et al, 1992] are sent back to a central laboratory for analysis [Novelli et al, 1992].…”

Section: Introductionmentioning

confidence: 99%

“…The CO source strength is stronger in the northern hemisphere (NH) than in the southern hemisphere (SH), and the atmospheric lifetime of a few months for CO is less than the hemispheric mixing time of a year, leading to higher concentrations in the Nit, The seasonal variation is in excess of 100 ppbv at Barrow (71.32 ø N), between 40-60 ppbv at 20øN [Novelli et al, 1992] are sent back to a central laboratory for analysis [Novelli et al, 1992]. A gas filter radiometer has been deployed on the space shuttle for several missions [Reichle et al, 1986;1990]. This instrument has the potential of mapping the atmospheric CO concentration from a single spaceborne platform.…”

Section: Introductionmentioning

confidence: 99%