排序方式： 共有4条查询结果，搜索用时 62 毫秒
1
1.
Joanne H. Shorter J. Barry Mcmanus Charles E. Kolb Eugene J. Allwine Brian K. Lamb Byard W. Mosher Robert C. Harriss Uwe Partchatka Horst Fischer Geoffrey W. Harris Paul J. Crutzen Hans-Josef Karbach 《Journal of Atmospheric Chemistry》1996,24(2):121-140
We have investigated methane emissions from urban sources in the former East Germany using innovative measurement techniques including a mobile real-time methane instrument and tracer release experiments. Anthropogenic and biogenic sources were studied with the emphasis on methane emissions from gas system sources, including urban distribution facilities and a production plant. Methane fluxes from pressure regulating stations ranged from 0.006 to 24. l/min. Emissions from diffuse sources in urban areas were also measured with concentration maps and whole city flux experiments. The area fluxes of the two towns studied were 0.37 and 1.9 g/m2/s. The emissions from individual gas system stations and total town emissions of this study are comparable to results of similar sites examined in the United States. 相似文献
2.
R. Dubois H. Flentje F. Heintz H. J. Karbach U. Platt 《Journal of Atmospheric Chemistry》1997,28(1-3):97-109
Long Path Different Optical Absorption measurements of theconcentrations of O3, NO2, NO3 andSO2 were carried out at Cape Arkona, Island Rügen, nearthe well-known long-term ozone registration. A statistical analysis ofdifferent trace gas concentrations for all seasons is presented. Daytimedata, wind speed and sector-classified results are used to estimaterepresentative ozone concentrations. Comparison of the long path ozonemeasurements with point measurements at Cape Arkona shows ozoneconcentration differences. 相似文献
3.
Hans-Josef Knab 《Geochimica et cosmochimica acta》1981,45(9):1563-1572
12 carbonaceous chondrites, amongst them representatives of nearly all known petrologic types were analyzed for twenty trace elements by spark source mass spectrography combined with the isotope dilution method. Data on different element groups (refractory, moderately volatile and volatile) show that the distribution of the trace elements in the carbonaceous chondrites, with the exception of Renazzo, can be well explained by Anders' two-component model. This is also valid for the highly metamorphosed CV5 chondrite Karoonda.Furthermore, it is observed that the -ratios in the carbonaceous chondrites increase with increasing petrologic type which is interpreted as the result of mixing two components with different -ratios 相似文献
4.
The effect of cloud feedback on the response of a radiative-convective model to a change in cloud model parameters, atmospheric CO2 concentration, and solar constant has been studied using two different parameterization schemes. The method for simulating the vertical distribution of both cloud cover and cloud optical thickness, which depends on the relative humidity and on the saturation mixing ratio of water vapor, respectively, is the same in both approaches, but the schemes differ with respect to modeling the water vapor profile. In scheme I atmospheric water vapor is coupled to surface parameters, while in scheme II an explicit balance equation for water vapor in the individual atmospheric layers is used. For both models the combined effect of feedbacks due to variations in lapse rate, cloud cover, and cloud optical thickness results in different relationships between changes in surface temperature, planetary temperature, and cloud cover. Specifically, for a CO2 doubling and a 2% increase in solar constant, in both models the surface warming is reduced by cloud feedback, in contrast to no feedback, with the greater reduction in scheme I as compared to that of scheme II. 相似文献
1