Showing papers on "Atmospheric methane published in 1984"
TL;DR: In this paper, an analysis of air bubbles buried long ago in polar ice makes it possible to deduce the concentrations of methane in the old and ancient atmospheres, finding that the present concentration of methane may be more than twice as high as the natural levels of 150 years ago.
Abstract: Rasmussen and Khalil (1981) have shown that the concentration of methane is increasing in the earth's atmosphere. A continuing increase of methane may perturb the global environment in the future by warming the earth and leading to more ozone and carbon monoxide in the atmosphere. It appears that the present concentration of methane may be more than twice as high as the natural levels of 150 years ago. An analysis of air bubbles buried long ago in polar ice makes it possible to deduce the concentrations of methane in the old and ancient atmospheres. The present investigation is concerned with the results of an analysis of more than 80 ice core samples, taking into account both polar regions of the earth. The samples range in age from about 100 to nearly 3000 years old. It is found that the concentration of methane started changing significantly about 150 years ago. These findings suggest that the increase of methane is probably indirectly caused by the rapid increase of human population.
294 citations
TL;DR: In this article, a numerical model employing the residual Eulerian formulation and small eddy diffusivity coefficients is used to calculate the distributions of chemical tracers and chlorine species, and the predicted densities of nitrous oxide, methane, and chlorocarbons are shown to be in good agreement with available observations and to exhibit strong latitude gradients.
Abstract: A numerical model employing the residual Eulerian formulation and small eddy diffusivity coefficients is used to calculate the distributions of chemical tracers and chlorine species. The predicted densities of nitrous oxide, methane, and chlorocarbons are shown to be in good agreement with available observations and to exhibit strong latitude gradients. Computed spatial variations in methane produce large variations in the HCl and ClO densities. In particular, a pronounced local minimum in HCl is obtained near 40 km for certain latitudes and seasons, with a corresponding maximum in ClO, primarily as a result of transport of atmospheric methane. It is suggested that spatial and short-term temporal variability in methane has potentially important consequences for the HCl and ClO distributions in the atmosphere, and their variability, and for the chlorine-catalyzed destruction of stratospheric ozone.
106 citations
TL;DR: The results of a six year measurement of trace gases in 18 different urban and remote areas throughout the Northern and Southern Hemispheres are reported in this paper, which is consistent with a yearly atmospheric release of 30 to 60 megatons of CH4 in urban environments.
Abstract: The results of a six year measurement of trace gases in 18 different urban and remote areas throughout the Northern and Southern Hemispheres are reported. It is found that the measurements are consistent with a yearly atmospheric release of 30 to 60 megatons of CH4 in urban environments. Concentrations of CCl3F, CCl2F2, and CH3CCl3 were also found to be higher in the same urban samples than in corresponding samples from remote areas. The 'urban excess' (urban concentration minus remote concentration) was generally 1000 to 2000 times larger on a molar basis for CH4 than for CCl3F. The fraction of world-wide methane release occurring in the urban environment is estimated from the concentration ratios for CH4 vs CCl3F. It is shown that about 8 to 15 percent of atmospheric methane release occurs in urban areas.
31 citations
TL;DR: Atmospheric methane over the past 27,000 years was measured by analyzing air trapped in glacial ice in Greenland and Antarctica; the change in concentration is correlated with the increase in human population; the implications for climate modification are discussed.
Abstract: Atmospheric methane over the past 27,000 years was measured by analyzing air trapped in glacial ice in Greenland and Antarctica. Atmospheric concentrations were stable over that period until about 200 years b.p. In the last 200 years they have more than doubled. This change in concentration is correlated with the increase in human population; the implications for climate modification are discussed. 1 figure, 3 references.
10 citations
TL;DR: A validated band model for atmospheric methane (CH4) in the 1085–1755- and 2370–3215-cm−1 wave-number regions is presented and a vertical profile of methane’s volume mixing ratio is proposed for use with the thirty-three-layer standard atmosphere.
Abstract: A validated band model for atmospheric methane (CH4) in the 1085–1755- and 2370–3215-cm−1 wave-number regions is presented. Discussions of the transmittance data base used to create the model and of the band parameter determination scheme are given. Comparisons of the model vs methane transmittance are provided. Band model parameters at 5-cm−1 intervals for 20-cm−1 spectral resolution throughout the absorption bands are included for direct incorporation into the lowtran code. A vertical profile of methane’s volume mixing ratio is also proposed for use with the thirty-three-layer standard atmosphere.
3 citations
TL;DR: Lunine et al. as discussed by the authors suggested that Titan's atmospheric methane may have broken down by a catalyzed photochemical reaction to ethane (C2H6), and the resulting ocean would consist of a mixture of C 2H6 and CH4 in the proportion of 3 to 1.
Abstract: Detection of the atmosphere of Saturn's satellite Titan by the Voyager I spacecraft indicated an abundance of only 3 mol % methane (CH4). Recently J.I. Lunine, D.J. Stevenson, and Y.L. Yung calculated that 3 mol % methane is sufficiently low to preclude the stable coexistence of liquid methane on Titan's surface, which has a temperature of 94 K (Science, 222, 1229, 1983). Instead, Lunine et al. suggest that Titan's atmospheric methane may have broken down by a catalyzed photochemical reaction to ethane (C2H6). The resulting ocean would consist of a mixture of C2H6 and CH4 in the proportion of 3 to 1.
2 citations
Journal Article•
1 citations