摘要:

On August 15–17, 1972, a joint meeting was held in St. Petersburg, Florida, under the aegis of the American Geophysical Union and the American Meteorological Society on Sources, Sinks, and Concentrations of Carbon Monoxide and Methane in the Earth's Environment.In addition to the societies that endorsed it, four governmental agencies sponsored the meeting: Department of Transportation, Environmental Protection Agency, National Aeronautics and Space Administration, and National Oceanic and Atmospheric Administratio

ISSN:0148-0227    

DOI:10.1029/JC078i024p05247

年代:1973

数据来源: WILEY

摘要:

A survey of the concentrations of light hydrocarbons in the Gulf of Mexico has been made aboard the R.V.Alaminosof Texas A&M University. The hydrocarbon analyzer consists of a modified Beckman process gas chromatograph with a flame ionization detector. For surface profiling, gases are ‘stripped’ from seawater taken 3 meters below the sea surface by vacuum extraction with a 12‐stage booster pump. These gases are injected periodically into the gas stream of the chromatograph for analysis. The system also has the capability of analyzing discrete seawater samples either by the method of McAullife or by the method of Swinnerton and his co‐workers. Coastal waters of the Gulf of Mexico are not in equilibrium with the atmosphere insofar as low molecular weight hydrocarbons are concerned, even though methane in most of the open Gulf of Mexico is in fairly close equilibrium with the atmosphere. The coastal waters of the gulf act both as a source and as a sink for atmospheric methane. The important man‐derived sources of methane in the gulf are ports with their associated shipping and industrial activity, offshore petroleum drilling and production operations, and open ocean shipping activity. High light hydrocarbon concentrations have been found in the vicinity of a tanker discharging ‘clean ballast water.’ The important natural sources include seepage from oil and gas reservoirs and anaerobic production of methane. The main sink for atmospheric methane in the Gulf of Mexico is in the Yucatan area, where there is major upwelling of deep water with low hydrocarbon c

ISSN:0148-0227    

DOI:10.1029/JC078i024p05248

年代:1973

数据来源: WILEY

摘要:

The absorption due to the ν3band of methane at a wavelength of 3.3 μm has been observed in solar spectra taken with a balloon‐borne monochromator during its ascent from 13 to 28 km and during the float period at peak altitude until sunset. Measurements of the equivalent widths of theR(5) andR(6) lines were used in a single‐layer iterative calculation to determine methane abundance as a function of altitude. The Voigt line profile was used throughout. The mixing ratio obtained during the ascent decreases from 0.9 ppmv (parts per million by volume) at 13 km to 0.7 ppmv at 28 km. The variation of equivalent width with solar zenith angle during the float period is interpreted to indicate a rapid decline in mixing ratio above

ISSN:0148-0227    

DOI:10.1029/JC078i024p05259

年代:1973

数据来源: WILEY

摘要:

Vertical profiles of the CH4mixing ratio in the troposphere and stratosphere were obtained by collecting air samples and analyzing their CH4concentrations by gas chromatography. Two sets of tropospheric profiles, each covering a full year, have been measured; one over the Pacific 200 km offshore from Santa Barbara, California, and one over Scottsbluff, Nebraska. Although some of the individual profiles showed large fluctuations with time and space, a systematic seasonal variation of tropospheric CH4concentration could not be established. On a 1‐year average, CH4has a nearly uniform distribution in the troposphere, with an average volume mixing ratio of 1.41 ppmv. The only systematic gradient in the troposphere was observed for the Scottsbluff profiles which showed a decrease in the CH4mixing ratio close to the ground. In contrast, the stratospheric CH4profiles showed a systematic decrease with altitude, with a steeper gradient directly above the tropopause. The gradient appears to be weaker at higher altitudes. At 50 km the CH4mixing ratio has dropped to 0.25 ppm

ISSN:0148-0227    

DOI:10.1029/JC078i024p05265

年代:1973

数据来源: WILEY

摘要:

A grating spectrometer with a Ge/Cu detector was flown on several balloon flights during which the variation of the infrared solar spectrum in the 3‐ to 5‐μ region was recorded. Atmospheric absorption spectra were obtained at various altitudes from ground through 30 km with a resolution of ∼0.3 cm−1. Intense CO lines from bothPandRbranches are observed in the 2150‐cm−1region. In particular, theR(2) andR(3) lines in the (1–0) fundamental ban are clearly isolated from the neighboring H2O and N2O lines, so that the vertical distribution of CO in the atmosphere can be determined from these lines. A line‐by‐line, layer‐by‐layer computer program has been developed that derives the CO amounts in a layered atmosphere where the layers are defined by the actual altitudes of observations. The resulting altitude profile shows that the CO concentration between 4 and 15 km is gradually decreasing from ∼8

ISSN:0148-0227    

DOI:10.1029/JC078i024p05273

年代:1973

数据来源: WILEY

摘要:

Recent studies of electron energy deposition in CO2and CO based upon a large set of electron impact cross sections are utilized to estimate the telluric CO directly produced by various charged particle deposition mechanisms. We consider (1) lightning, (2) cloud coronal discharges, (3) background radioactivity, (4) natural electrostatic discharges, (5) photoelectrons in the ionosphere, (6) auroral electrons, (7) auroral protons, (8) cosmic rays, and (9) solar wind. We give ‘ball park’ estimates of the global CO production by each of these mechanisms. Apart from mechanisms 1, 2, and 5, all CO production mechanisms are estimated to be small compared to artificial sources. If, as appears to be the case, the hot oxygen atoms and ions and other atomic species immediately produced by these three charged particle deposition mechanisms react rapidly with CO2to produce CO, these mechanisms can readily lead to CO production levels in the multimegaton per year ra

ISSN:0148-0227    

DOI:10.1029/JC078i024p05284

年代:1973

数据来源: WILEY

摘要:

Carbon monoxide, the most abundant air pollutant found in the community atmosphere, generally exceeds the mass of all other air pollutants combined (excluding CO2). Total annual tonnages of CO from man‐made sources exceeded 132 × 106metric tons (146 × 106short tons) in the United States and 359 × 106metric tons (396 × 106short tons) globally in 1970. The largest single technological source of CO is the internal combustion engine. The atmospheric CO abundance in the biosphere in urban areas, where man resides, is not uniformly distributed and is dominated by anthropogenic sources. Community concentrations are quite variable and unequally distributed, being related to proximity to anthropogenic sources, patterns of human activity, and meteorological factors. These concentrations range from about 1 to>70 ppm and have brief peak levels in dense traffic as high as 140 ppm. The removal of CO from the atmosphere, as well as the sources and dispersion, controls the local concentration. Temporal characteristics of community CO concentrations are described. Although localized buildup of CO in cities may still represent a serious health hazard, man's CO production considered on a global basis is relatively minor in comparison with production from the larger natural sources. These include the atmospheric oxidation of methane, the ocean, decay of chlorophyll in plants, and terpene oxidation from plant sources. Their total source strength is estimated as 3–25 times the man‐made sources in the atmosphere as a whole. Background concentrations, a product of both natural and anthropogenic sources, normally range from 0.04 to 0.20 ppm, occasional concentrations being as high as 0.80 ppm at ground level in remote clean air areas, the higher concentrations being found in the northern h

ISSN:0148-0227    

DOI:10.1029/JC078i024p05293

年代:1973

数据来源: WILEY

摘要:

The numerical simulation of the troposphere including a nitrogen‐oxygen‐carbon‐hydrogen atmosphere has been accomplished for homogeneous time dependent static chemistry, employing 30 species and approximately 70 reactions, by using the Keneshea code. The objectives have included the obtaining of the effective homogeneous chemical lifetimes of each species to compare with transport and residence times, quantification of the rates of production of species associated with the carbon monoxide source‐sink anomaly for comparison with heterogeneous anthropogenic introduction, and a validation of the simpler steady state models of the troposphere. Particular attention has been given to the Weinstock‐Niki‐Levy mechanism for the conversion of CH4to CO via OH attack. Their conclusion that the decomposition of methane is potentially a much larger global source of CO than fossil fuel combustion is verified. Hydroxyl radical concentrations are sufficiently high to predict a CO chemical lifetime of 0.1 year, in general agreement with the carbon dating conclusions of Weinstock. Diurnal variations of the pertinent species concentrations ar

ISSN:0148-0227    

DOI:10.1029/JC078i024p05306

年代:1973

数据来源: WILEY

摘要:

Methane concentrations have been measured in the surface waters and at depth for several different marine environments. Measurements have also been made in rain water collected in Washington, D.C., over the Pacific Ocean, and in Hawaii. In tropical open ocean areas, surface water concentrations average 4.5 × 10−5ml/l and decrease to values approaching 0.6 × 10−5ml/l at a depth of 5000 meters. In natural anoxic conditions (i.e., Cariaco Trench, Black Sea, Lake Nitinat) concentrations can increase as much as four orders of magnitude. In the case of Lake Nitinat, 1.6 ml/l is found at a depth of 200 meters. Nearshore and bay concentrations can be 2–3 orders of magnitude higher than open ocean surface values. Open ocean surface waters are slightly supersaturated with methane, whereas estuary systems are highly supersaturated. Open ocean surface values remain fairly constant, whereas bay and river systems vary considerably, depending on the time of year, addition of pollutants, and tidal mixing. Rain water analyses yielded an average concentration of 5.0 × 10−5ml/l for the Hawaiian and Pacific samples, and an average concentration of 8.8 × 10−5ml/l was found for the Washington, D.C., area. Atmospheric methane concentrations over the open ocean remain fairly constant at 1.4 ppm. Atmospheric values in Washington, D.C., at NRL ave

ISSN:0148-0227    

DOI:10.1029/JC078i024p05317

年代:1973

数据来源: WILEY

摘要:

A tropospheric photochemical model is presented that provides a homogeneous gas phase radical chain mechanism for the removal of tropospheric methane, carbon monoxide, molecular hydrogen, and formaldehyde. The chain reaction that destroys methane serves as the tropospheric source for formaldehyde, which in turn serves as the major source of tropospheric carbon monoxide and molecular hydrogen. Simple relationships between methane and its destruction products are derived that give a surface mixing ratio for carbon monoxide of 0.1 ppm, independent of the radical number densities, and an upper limit for formaldehyde mixing ratio of 1 ppb. Detailed calculations of total column production and loss rates based on earlier calculated altitude profiles for the number densities of the hydroxyl radical and formaldehyde yield the following: For methane, a total column loss rate of 4.5 × 1011molecules/cm2sec and a tropospheric residence time of 2 years; for carbon monoxide, a total column production of 4.5 × 1011molecules/cm2sec, a tropospheric residence time of 0.1 year (assuming the measured value of 0.12 ppm for the carbon monoxide mixing ratio), and a uniform mixing ratio of 0.07 ppm based solely on atmospheric destruction and production; for molecular hydrogen, a column production rate of 1.6 × 1011molecules/cm2sec, a uniform mixing ratio of 0.7 ppm, and a tropospheric residence time of 2 yea

ISSN:0148-0227    

DOI:10.1029/JC078i024p05325

年代:1973

数据来源: WILEY