Search Results - (Author, Cooperation:P. J. Fraser)

2014-09-12

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Air Pollutants/chemistry ; Atmosphere/*chemistry ; Chloroform/chemistry ; Computer Simulation ; Hydroxyl Radical/*chemistry ; *Models, Theoretical ; Nitrogen Oxides/chemistry

1365-2109

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Abstract. The stomach contents of 256 Atlantic salmon, Salmo salar L., of fork lengths 53–66cm, caught in bag nets on the Scottish west coast near Ullapool, were examined between June 1983 and July 1986. A total of 61 fish contained fish in the stomach or had faecal pellets containing fish bones in the gut. All recognizable whole fish were sandeels, Ammodytes marinus Raitt, ranging in size from 4.5 to 15cm. No evidence for crustacean or other non-fish prey items was found. Results indicate that feeding salmon were caught up to a certain cut-off point in June or early July, after which all salmon sampled were not feeding. It is suggested that either there is a local feeding stock of salmon or that fish feed during migration from the Faroe Isles or other possible distant water origins.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Five-year blocks were taken from two King Billy pines (Arthrotaxis selaginoides D. Don) which grew within 200m of each other in natural forest in mountains of northern Tasmania (Fig. 1). A total of 71 separate burns were made on the 25 5-yr blocks of one tree and the CO2 from each burn analysed at ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] The ice core (BHD) used was thermally drilled to a depth of 473 m near the summit of Law Dome, Antarctica (6643' S, 11250'E; 1,375m) by the Australian National Antarctic Research Expedition in 1977. High precipitation rates (0.65 m yr"1), lack of melting at the firn surface (annual average ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Cumulative CC13F emissions including 1979 are 2.1% higher than used in a previous study5, based on a revised estimate of global releases up to 1980 6, incorporating previously unaccounted for CC13F losses at production sites (1.5% increase in total emissions over the period 1935-79), enhanced ...

Electronic Resource

1573-0662

Methane ; troposphere ; southern hemisphere ; trend ; annual cycle ; vertical gradient

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract Results of more than 800 new measurements of methane (CH4) concentrations in the Southern Hemisphere troposphere (34–41° S, 130–150° E) are reported. These were obtained between September 1980 and March 1983 from the surface at Cape Grim, Tasmania, through the middle (3.5–5.5 km) to the upper troposphere (7–10 km). The concentration of CH4 increased throughout the entire troposphere over the measurement period, adding further support to the view that CH4 concentrations are currently increasing on a global scale. For data averaged vertically through the troposphere the rate of increase found was 20 ppbv/yr or 1.3%/yr at December 1981. In the surface CH4 data a seasonal cycle with a peak to peak amplitude of approximately 28 ppbv is seen, with the minimum concentration occurring in March and the maximum in September–October. A cycle with the same phase as that seen at the surface, but with a significantly decreased amplitude, is apparent in the mid troposphere but no cycle is detected in the upper tropospheric data. The phase and amplitude of the cycle are qualitatively in agreement with the concept that the major sink for methane is oxidation by hydroxyl radicals. Also presented is evidence of a positive vertical gradient in methane, with a suggestion that the magnitude of this gradient has changed over the period of measurements.

Electronic Resource

1573-0662

Carbon tetrachloride ; fluorocarbons ; atmospheric releases

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract Seven years of daily gas chromatographic measurements of CCl4 at the five globally distributed ALE/GAGE surface sites are reported. It is determined that CCl4 has been accumulating in the atmosphere at a rate of 1.3±0.1%/yr over the period 1978–1985 and that the releases of CCl4 into the atmosphere have remained fairly constant, with the smallest releases in 1981–1982. Using an inversion scheme based on a nine box model of the atmosphere, we infer a CCl4 lifetime of approximately 40 yr, an inventory on 1 July 1978 of (2.08±0.07)×109 kg and an average rate of release over the period 1978–1985 of (0.9±0.9)×107 kg/yr. These results produce excellent agreement with a release scenario derived from global production estimates for CCl4 and the major CCl4 byproduct, the chlorofluorocarbons. However, to obtain this consistency, it is necessary that our current ALE/GAGE absolute calibration standard be reduced approximately 25% thus bringing it into agreement with measurements by Yokohata et al. (1985) and Hanst et al. (1975).

Electronic Resource

1573-0662

nitrous oxide (N2O ; flux ; Australia ; radon ; rainfall dependence

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract Nitrous oxide (N2O) fluxes for south-easternAustralia have been estimated using a combination ofthe in situ N2O and radon (Rn) measurementsmade at the Cape Grim Baseline Air Pollution Station,in north-west Tasmania. The average N2O fluxesfrom the south-eastern mainland of Australia and fromTasmania over the nine years of record analysed (1985–1993) have beenfound to be 130 ± 30 kgN km-2yr-1 and 160 ± 45 kgN km-2yr-1respectively. These fluxes are larger than expectedand a significant dependence of the flux on rainfallis observed, with greater fluxes in the spring (October–December) andduring periods of positive SouthernOscillation Index. A large flux (1,300 ± 500kgN km-2 yr-1) from a nearby island (KingIsland) was also estimated from the data record,indicating a strong source, although the small size ofthe island means that it is not a significant sourcefor Australia.

Electronic Resource

1573-0662

Methane ; methylchloroform ; carbon monoxide ; Southern Hemisphere ; trends ; seasonal cycles ; hydroxyl radical ; tow dimensional model ; methane source function

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract New observational data on CH4, CO and CH3CCl3 in the southern hemisphere are reported. The data are analysed for long term trends and seasonal cycles. CH3CCl3 data are used to scale the OH fields incorporated in a two dimensional model, which in turn, is used to constrain the magnitude of a global CH4 source function. The possible causes of observed seasonality of CH3CCl3, CH4 and CO are identified, and several other aspects of observed CH4 variability are discussed. Possible future research directions are also given.

Electronic Resource

1573-0662

Methane ; termites ; global methane budget

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract New CH4 emission data from a number of Northern and Southern Hemispheric, tropical and temperate termites, are reported, which indicate that the annual global CH4 source due to termites is probably less than 15 Tg. The major uncertainties in this estimate are identified and found to be substantial. Nevertheless, our results suggest that termites probably account for less than 5% of global CH4 emissions.

Electronic Resource

1573-0662

Methane ; troposphere ; global distribution ; trend ; seasonal cycle ; latitudinal gradient ; vertical gradient

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract Methane has been measured in air samples collected at approximately weekly intervals at 23 globally distributed sites in the NOAA/GMCC cooperative flask sampling network. Sites range in latitude from 90° S to 76° N, and at most of these we report 2 years of data beginning in early 1983. All measurements have been made by gas chromatography with a flame ionization detector at the NOAA/GMCC laboratory in Boulder, Colorado. All air samples have been referenced to a single secondary standard of methane-in-air, ensuring a high degree of internal consistency in the data. The precision of measurements is estimated from replicate determinations on each sample as 0.2%. The latitudinal distribution of methane and the seasonal variation of this distribution in the marine boundary layer has been defined in great detail, including a remarkable uniformity in background levels of methane in the Southern Hemisphere. We report for the first time the observation of a complete seasonal cycle of methane at the South Pole. A significant vertical gradient is observed between a sea level and a high altitude site in Hawaii. Globally averaged background concentrations in the marine boundary layer have been calculated for the 2 year-period May 1983–April 1985 inclusive, from which we find an average increase of 12.8 ppb per year, or 0.78% per year when referenced to the globally averaged concentration (1625 ppb) at the mid-point of this period. We present evidence that there has been a slowing down in the methane growth rate.

Electronic Resource