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71.
Detlef P. van Vuuren Bert de Vries Arthur Beusen Peter S.C. Heuberger 《Global Environmental Change》2008,18(4):635
The conditional probabilistic scenario analysis combines statistical methods of uncertainty analysis at parameter level with storylines which recognize the deep uncertainty that exists for several underlying trends. The model calculations indicate that cumulative 21st century emissions could range from 800 to 2500 GtC in the absence of climate policy. This range originates partly from the underlying storylines, and partly from the probabilistic analysis. Among the most important parameters contributing to the uncertainty range are uncertainty in income growth, population growth, parameters determining energy demand, oil resources and fuel preferences. The contribution of these factors is also scenario-dependent. 相似文献
72.
Laser microprobe for the study of noble gases and nitrogen in single grains: A case study of individual chondrules from the Dhajala meteorite 总被引:1,自引:0,他引:1
A laser microprobe capable of analysing nitrogen and noble gases in individual grains with masses less than a milligram is
described. It can be used in both continuous wave (CW) mode, useful for stepwise heating of an individual grain, as well as
in pulsed mode, useful for ablating material from a small selected area of a sample, for gas extraction. We could achieve
low blanks (in ccSTP units) for 4He(4.8 x 10{-12}),22Ne(1.0 x 10{-12}),36Ar(1.0 x10
-13),84Kr(2.9 x 10{-14}),132 Xe(2.6 x 10{-14}), and N (87 pg), using this system. Preliminary data for individual chondrules from the Dhajala meteorite show that noble
gases and nitrogen from grains as small as 170 microgram can be analysed using the present laser microprobe setup. The amount
of trapped neon in Dhajala chondrules is very small, and nitrogen in the chondrules is isotopically heavier as compared to
the bulk meteorite. 相似文献
73.
Summary After a brief review on recent experimental work on the uptake resp release of SO2 and NH3 by the ocean, new results on the distribution of these reactive trace-gases in the marine atmosphere are presented. In the case of SO2 there is no doubt that the ocean acts as a sink. In the case of NH3 new observations and calculations show that under certain conditions the ocean may be a NH3 source. 相似文献
74.
Sources and sinks of atmospheric methane 总被引:7,自引:0,他引:7
In 1972 average mixing ratio of methane in the troposphere was 1.41 ppm and 1.3 ppmv for the northern and southern hemisphere, respectively, which corresponds to a total amount of 4×1015 g of CH4 present in the atmosphere. Most is of recent biologic origin.14C analyses show that no more than 20 percent is released by fossil sources. The various ecosystems producing CH4 are discussed and the total annual production is estimated to lie between 5.5×1014 g/yr and 11×1014 g/yr. The corresponding turnover times for atmospheric CH4 range from 4 to 7 yrs. The destruction of CH4 takes place mainly in the troposphere, most probably through the reaction of CH4 + OH CH3 + H2O. About 10 percent of the CH4 is destroyed in the stratosphere. The CH4 cycle contributes on the order of 1 percent to the atmospheric carbon cycle. 相似文献
75.
Natural gas generation model and its response in accumulated fluids in the Yinggehai basin 总被引:2,自引:0,他引:2
The generation of natural gases is much more complicated in comparison with liquid petro-leum in that natural gases could be generated from both humic and sapropelic organic matter at different stages and that natural gases could be organic and inorganic … 相似文献
76.
Grayna Ceglarska-Stefaska Katarzyna Zarbska 《International Journal of Coal Geology》2005,62(4):211-222
The paper reports the results of experiments concerning the sorption/desorption processes, observed under laboratory conditions, in two types of coal extracted from operational coal-mines in Poland, using CH4 and CO2 to observe their relative inter-reaction with the coal samples when introduced in varying proportions and conditions. Numerous studies concerning the sorption/desorption phenomena have described the operational mechanisms and the relationship of mine gases to the organically-created coal-body in mines. The differences in the behaviour of certain gases is twofold: firstly the essentially different characteristics of CO2 and CH4, and secondly the structure of the coal-bed itself: its degree of metamorphism and content of macerals. From the results yielded, it was observed that the divergence of the isotherms of sorption of CH4 and other gases in comparison with the isotherms of sorption of CO2 and a CO2/CH4 mixture differed and that the curve on the sorption isotherm was more clearly distinct after the introduction of CO2 molecules to the system: coal with a higher degree of metamorphism—CH4, which is closely related to the rigidity of the structure according to the level of metamorphism. Since coals with higher carbon content exhibit lower molecular bonding than low-carbonised coals, the characteristic feature of the bonds in the first case is their mobility. Knowledge of the physical and chemical properties of hard coals, as well as their interaction with mining gases, is of great use in solving problems concerned with the extraction of methane from mines or its storage in goafs. 相似文献
77.
78.
T. Wang H. Guo D. R. Blake Y. H. Kwok I. J. Simpson Y. S. Li 《Journal of Atmospheric Chemistry》2005,52(3):295-317
We present a 16-month record of ozone (O3), carbon monoxide (CO), total reactive nitrogen (NOy), sulphur dioxide (SO2), methane (CH4), C2 – C8 non-methane hydrocarbons (NMHCs), C1 – C2 halocarbons, and dimethyl sulfide (DMS) measured at a southern China coastal site. The study aimed to establish/update seasonal
profiles of chemically active trace gases and pollution tracers in subtropical Asia and to characterize the composition of
the `background' atmosphere over the South China Sea (SCS) and of pollution outflow from the industrialized Pearl River Delta
(PRD) region and southern China. Most of the measured trace gases of anthropogenic origin exhibited a winter maximum and a
summer minimum, while O3 showed a maximum in autumn which is in contrast to the seasonal behavior of O3 in rural eastern China and in many mid-latitude remote locations in the western Pacific. The data were segregated into two
groups representing the SCS background air and the outflow of regional continental pollution (PRD plus southern China), based
on CO mixing ratios and meteorological conditions. NMHCs and halocarbon data were further analyzed to examine the relationships
between their variability and atmospheric lifetime and to elucidate the extent of atmospheric processing in the sampled air
parcels. The trace gas variability (S) versus lifetime (τ) relationship, defined by the power law, Slnx = Aτ− b, (where X is the trace gas mixing ratio) gives a fit parameter A of 1.39 and exponent b of 0.42 for SCS air, and A of 2.86 and b of 0.31 for the regional continental air masses. An examination of ln[n-butane]/ln[ethane] versus ln[propane]/ln[ethane] indicates that their relative abundance was dominated by mixing as opposed
to photochemistry in both SCS and regional outflow air masses. The very low ratios of ethyne/CO, propane/ethane and toluene/benzene
suggest that the SCS air mass has undergone intense atmospheric processing since these gases were released into the atmosphere.
Compared to the results from other polluted rural sites and from urban areas, the large values of these species in the outflow
of PRD/southern China suggest source(s) emitting higher levels of ethyne, benzene, and toluene, relative to light alkanes.
These chemical characteristics could be unique indicators of anthropogenic emissions from southern China. 相似文献
79.
西藏地热气体的地球化学特征及其地质意义 总被引:9,自引:3,他引:9
西藏水热活动是青苦恼高原碰撞造山过程的产物,其成因类型、物质来源和时空分布与青藏高原的隆升过程密切相关,地热流体(气、液相)中携带有中上地壳乃至地幔物质的深部信息。西藏地热流体可以区分出CO2型和N2型两类气体,其中绝大多数的地热气体样品属于CO2型气体,而典型的N2型气体则较少。前者具有岩浆热源和深循环两种成因类型,后者都是深循环成因。西藏气体样品中的He含量变化范围非常宽,最高的可达到1.5%。在门士热泉,首次检测到地幔He组分,这说明西藏地壳深处有地幔物质侵位。根据He同位素组成推断,羊八井、谷露等处的地壳熔融体中约有3%的地幔组分。西藏地热气体中的N2和Ar组分主要是大气成因,CO2组分大多以海相碳酸盐岩成因为主,混有少量有机沉积物成因CO2。当Log(H2/Ar)处于-0.8-0.3的区间时,H2/Ar地热温度计可以良好地指示热储层的温度范围。实际调查表明:西藏水热活动区大多分布在斑公错-怒江链合带以南地区,高温水热活动区主要出现在雅鲁藏布缝合带和那曲-羊八井-亚东活动构造带沿线。 相似文献
80.