Search Results - (Author, Cooperation:I. G. Enting)
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1Latest Papers from Table of Contents or Articles in PressS. Houweling ; B. Badawy ; D. F. Baker ; S. Basu ; D. Belikov ; P. Bergamaschi ; P. Bousquet ; G. Broquet ; T. Butler ; J. G. Canadell ; J. Chen ; F. Chevallier ; P. Ciais ; G. J. Collatz ; S. Denning ; R. Engelen ; I. G. Enting ; M. L. Fischer ; A. Fraser ; C. Gerbig ; M. Gloor ; A. R. Jacobson ; D. B. Jones ; M. Heimann ; A. Khalil ; T. Kaminski ; P. S. Kasibhatla ; N. Y. Krakauer ; M. Krol ; T. Maki ; S. Maksyutov ; A. Manning ; A. Meesters ; J. B. Miller ; P. I. Palmer ; P. Patra ; W. Peters ; P. Peylin ; Z. Poussi ; M. J. Prather ; J. T. Randerson ; T. Rockmann ; C. Rodenbeck ; J. L. Sarmiento ; D. S. Schimel ; M. Scholze ; A. Schuh ; P. Suntharalingam ; T. Takahashi ; J. Turnbull ; L. Yurganov ; A. Vermeulen
American Association for the Advancement of Science (AAAS)
Published 2012Staff ViewPublication Date: 2012-09-01Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Atmosphere/*chemistry ; Carbon Dioxide/*analysis ; *Climate ChangePublished by: -
2E-Books: DFG German National LicensesStaff View
Keywords: Atmospheric diffusion, Mathematical models. ; Dynamic meteorology, Mathematical models. ; Inverse problems (Differential equations)Notes: Principles -- Atmospheric transport and transport models -- Estimation -- Time series estimation -- Observations of atmospheric composition -- The sources and sinks -- Problem formulation -- Ill-conditioning -- Analysis of model error -- Green's functions and synthesis inversion -- Time-stepping inversions -- Non-linear inversion techniques -- Experimental design -- Recent Applications -- Global carbon dioxide -- Global methane -- Halocarbons and other global-scale studies -- Regional inversions -- Constraining atmospheric transportPages: xv, 392 p.ISBN: 0-511-06457-8URL: -
3Articles: DFG German National LicensesStaff View
ISSN: 1572-9613Keywords: Potts model ; triangular lattice ; Peierls argument ; low temperature series ; phase diagram ; relations with other lattice modelsSource: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract In this paper we study the 3-state Potts model on the triangular lattice which has two- and three-site interactions. Using a Peierls argument we obtain a rigorous bound on the transition temperature, thereby disproving a conjecture on the location of its critical point. Low-temperature series are generated and analyzed for three particular choices of the coupling constants; a phase diagram is then drawn on the basis of these considerations. Our analysis indicates that the antiferromagnetic transition and the transition along the coexistence line are of first order, implying the existence of a multicritical point in the ferromagnetic region. Relation of the triangularq-state Potts model with other lattice-statistical problems is also discussed. In particular, an Ashkin-Teller model and the hard-hexagon lattice gas solved by Baxter emerge as special cases in appropriate limits.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesStaff View
ISSN: 1572-9613Keywords: Lattice statistics ; series expansions ; corner transfer matricesSource: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract We have studied the hard-square lattice gas, using corner transfer matrices. In particular, we have obtained the first 24 terms of the high-density series for the order parameterρ 2−ρ 1. From these we estimate the critical activity to be 3.7962±0.0001. This is in excellent agreement with the earlier work of Gaunt and Fisher. It conflicts with the value 4.0 given by Müller-Hartmann and Zittartz's formula for the critical point of the antiferromagnetic Ising model in a field, so we conclude that this formula, while a good approximation, is not exact.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] In order to represent the relation between atmospheric concentrations and bubble concentrations, a negative time variable z (in years) is introduced. The variable z increases with depth and has its origin at the present (that is, the time at which the ice core was extracted). The atmospheric ...Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] Sirâáá¤Hammond et al. suggest1 that for political purposes the relative importance of greenhouse gas emissions from various countries should be based on the observed rate of increase of atmospheric concentraÂá-tion rather than on calculated ...Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesFraser, P. J. ; Hyson, P. ; Enting, I. G. ; Pearman, G. I.
[s.l.] : Nature Publishing Group
Published 1983Staff ViewISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [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 ...Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesFrancey, R. J. ; Tans, P. P. ; Allison, C. E. ; Enting, I. G. ; White, J. W. C. ; Trolier, M.
[s.l.] : Nature Publishing Group
Published 1995Staff ViewISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] We employ a simplified version of the global carbon and 13C budgets developed by Tans et al.4, to explore changes in d(δ13C)/ d/, where t is time. The budget relies on the fact7 that the product of total carbon and its isotopic ratio (Cxδ13C) is a conservative quantity in the ...Type of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesStaff View
ISSN: 1420-9136Keywords: Greens function ; Geochemical modelling ; Atmospheric chemistrySource: Springer Online Journal Archives 1860-2000Topics: GeosciencesPhysicsNotes: Abstract The use of Green's functions and response functions in modelling atmospheric and oceanic tracers is discussed. It is shown that low-resolution Green's function representations can describe tracer distributions more accurately than low-resolution models. The Green's function formalism is also used to discuss the problem of determining surface CO2 sources from observations of surface CO2 concentrations.Type of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesStaff View
ISSN: 1420-9136Keywords: Firn closure ; atmospheric composition ; bubble trappingSource: Springer Online Journal Archives 1860-2000Topics: GeosciencesPhysicsNotes: Abstract A mathematical description of the trapping of air bubbles in polar ice is analysed in order to assist in the interpretation of measurements of anthropogenic constituents which have recently increased on time scales comparable to the firn closure time. The effective age of a layer of ice is defined in terms of the time at which the atmospheric concentration of a constitutent was equal to the mean concentration for bubbles found in that layer. Under the assumption of uniform snow deposition at a particular site, the effective age is found to be the same for all constituents that vary linearly throughout the trapping period for a layer. Using a trapping distribution based on theoretical and observational studies, the corrections for non-linearity are found to be small for typical anthropogenic constituents. This property makes it possible to use smoothly increasing tracers such as the chlorofluorcarbons to determine the effective age empirically, even though, it is an extremely poorly-conditioned problem to determine the entire trapping time distribution function by inversion of tracer concentrations.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesStaff View
ISSN: 1573-1472Source: Springer Online Journal Archives 1860-2000Topics: GeosciencesPhysicsType of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesStaff View
ISSN: 1573-1480Source: Springer Online Journal Archives 1860-2000Topics: GeosciencesPhysicsNotes: Abstract The various limitations of a recent analysis of climatic variations in terms of solar volcanic and carbon dioxide forcing have been examined in more detail. In particular, the possibility of additional CO2 release from forest clearing greatly increases the very large statistical uncertainties in the original analysis. While the inclusion of the various forcing terms is a highly desirable approach, the uncertainties in the data used mean that it is not appropriate to suggest that ‘the surface warming due to the greenhouse effect has now been roughly determined’.Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesStaff View
ISSN: 1573-1480Source: Springer Online Journal Archives 1860-2000Topics: GeosciencesPhysicsNotes: Abstract The objectives of the Framework Convention on Climate Change imply the conflicting constraints of minimising concentrations and maximising emissions (i.e. minimising emission restrictions). Carbon cycle models are readily used for ‘forward’ calculations of future CO2 given specified emissions and the ‘inverse’ problem of deducing the emissions required to achieve specified concentration profiles. However these approaches (a) are each geared to only one side of the problem; and (b) each requires the specification of a particular pathway in terms of either emissions or concentrations. These limitations can be avoided by analysing the relations between future emissions and concentrations of CO2 using a formalism that optimises over all possible future emission profiles, subject to relevant constraints on both emissions and concentrations. We present specific calculations indicating which combinations of upper bounds on concentrations and lower bounds on emissions are mutually inconsistent and which are consistent. We also calculate the (smaller) consistency regions that apply if emission reductions are restricted to less than 0.5% p.a. or less than 1% p.a. In each case, two reference periods (1990-2100 and 1990-2200) are considered.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesStaff View
ISSN: 1573-0662Keywords: Inverse problems ; baseline monitoringSource: Springer Online Journal Archives 1860-2000Topics: Chemistry and PharmacologyGeosciencesNotes: Abstract The importance of ill-posed inverse problems in atmospheric chemistry is reviewed. Most models for the determination of sources and sinks of atmospheric constitutents lead to such ill-posed inverse problems. Consequently, source determinations may be subject to severe amplification of observational error, particularly in the most rapidly varying components. Therefore, mathematical analysis of the various inverse problems needs to be undertaken in order to determine the extent to which a given set of data contains usable information about source/sink processes.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesStaff View
ISSN: 1573-0662Keywords: Carbon dioxide ; interannual variations ; Southern Oscillation ; El NinoSource: Springer Online Journal Archives 1860-2000Topics: Chemistry and PharmacologyGeosciencesNotes: Abstract A method is described for the analysis of the interannual variability of background atmospheric carbon dioxide concentration. The analysis is carried out on the data from 6 observatories for which records of 〉8 years were available. A global-scale interannual variation of CO2 concentration in the troposphere with a characteristic time-scale of 2–3 years has been confirmed throughout the period of the records. These variations are estimated to be associated with carbon cycle imbalances of 2–3 Gt or annual net exchanges between the atmosphere and another carbon reservoir(s) at a rate of about 1.2 Gt of carbon per year. Lag correlations and amplitude comparisons between the records suggests a low latitude southern hemisphere origin to this phenomenon. The interannual variations of CO2 increase are found to be correlated with those observed in data for Pacific sea surface temperatures and Pacific witd stress, the Southern Oscillation Index and the Quasi-Biennial Oscillation. However multiple regression studies found that once the Southern Oscillation index is used as an explanatory variable for CO2 variations, the inclusion of additional geophysical variables does not give any significant improvement in the regression.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesStaff View
ISSN: 1572-9613Keywords: Square lattice polygonsSource: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract We consider the generating function of self-avoiding square lattice polygons grouped by both area and perimeter. The generating function for polygons of arean is found to diverge atx c =0.251834, with an exponent of zero. The mean perimeter of polygons with arean is found to be proportional ton, while the mean area of polygons with perimetern is found to be proportional ton 1.5.Type of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesStaff View
ISSN: 1572-9613Keywords: Lattice models ; series expansions ; corner transfer matricesSource: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract The corner transfer matrix formalism is used to obtain low-temperature series expansions for the square lattice Ising model in a field. This algebraic technique appears to be far more efficient than conventional methods based on combinatorial enumeration.Type of Medium: Electronic ResourceURL: