Homogeneous freezing of single sulfuric and nitric acid solution drops levitated in an acoustic trap     

Karoline Diehl  Matthias Ettner-Mahl  Anke Hannemann  Subir K. Mitra   《Atmospheric Research》2009,94(2):356-361

The freezing temperatures of single supercooled drops of binary and ternary sulfuric and nitric acid solutions were measured while varying the acid concentration. An acoustic levitator was used which allows to freely suspend single solution drops in air without electrical charges thereby avoiding any electrical influences which may affect the freezing process. The drops of typically 500 µm in radius were monitored by a video camera during cooling cycles down to − 85 °C to simulate the upper tropospheric and stratospheric temperature range. The present data confirm that liquid solution droplets can be supercooled far below the equilibrium melting point by approximately 35 °C. They follow the general trend of the expected freezing temperatures for homogeneous ice nucleation.  相似文献   

The OH site in topaz: an IR spectroscopic investigation     

Anke Watenphul  Eugen Libowitzky  Bernd Wunder  Matthias Gottschalk 《Physics and Chemistry of Minerals》2010,37(9):653-664

The OH site in topaz is investigated by IR spectroscopy depending on the OH concentration and temperature. The two OH bands that can be distinguished are due to the local ordering of F and OH in opposite sites of the crystal structure. The first typical sharp band stems from OH groups with fluorine in the opposite (=acceptor) site. The second band occurs as a shoulder on the low-energy wing and is related to two opposite OH groups. The degree of local OH–OH ordering depends on the OH concentration and, due to statistical F/OH distribution, can be predicted by probability calculations. The substitution of OH for F has a non-linear effect on the increase of the lattice parameters. An autocorrelation analysis of the IR spectra revealed two temperature-induced phase transitions. At −135°C, the local symmetry changes from P1 to Pbn2₁, although this change involves only the H atoms. The transition from Pbn2₁ to Pbnm at 160°C is caused by changes of the local F/OH ordering in the crystal structure.  相似文献   

Benefits of dealing with uncertainty in greenhouse gas inventories: introduction   总被引：2，自引：2，他引：0  

Matthias Jonas  Gregg Marland  Wilfried Winiwarter  Thomas White  Zbigniew Nahorski  Rostyslav Bun  Sten Nilsson 《Climatic change》2010,103(1-2):3-18

The assessment of greenhouse gases emitted to and removed from the atmosphere is high on the international political and scientific agendas. Growing international concern and cooperation regarding the climate change problem have increased the need for policy-oriented solutions to the issue of uncertainty in, and related to, inventories of greenhouse gas (GHG) emissions. The approaches to addressing uncertainty discussed in this Special Issue reflect attempts to improve national inventories, not only for their own sake but also from a wider, systems analytical perspective—a perspective that seeks to strengthen the usefulness of national inventories under a compliance and/or global monitoring and reporting framework. These approaches demonstrate the benefits of including inventory uncertainty in policy analyses. The authors of the contributed papers show that considering uncertainty helps avoid situations that can, for example, create a false sense of certainty or lead to invalid views of subsystems. This may eventually prevent related errors from showing up in analyses. However, considering uncertainty does not come for free. Proper treatment of uncertainty is costly and demanding because it forces us to make the step from “simple to complex” and only then to discuss potential simplifications. Finally, comprehensive treatment of uncertainty does not offer policymakers quick and easy solutions. The authors of the papers in this Special Issue do, however, agree that uncertainty analysis must be a key component of national GHG inventory analysis. Uncertainty analysis helps to provide a greater understanding and better science helps us to reduce and deal with uncertainty. By recognizing the importance of identifying and quantifying uncertainties, great strides can be made in ongoing discussions regarding GHG inventories and accounting for climate change. The 17 papers in this Special Issue deal with many aspects of analyzing and dealing with uncertainty in emissions estimates.  相似文献   

Deglacial history of the West Antarctic Ice Sheet in the western Amundsen Sea Embayment     

James A. Smith  Claus-Dieter Hillenbrand  Gerhard Kuhn  Robert D. Larter  Alastair G.C. Graham  Werner Ehrmann  Steven G. Moreton  Matthias Forwick 《Quaternary Science Reviews》2011,30(5-6):488-505

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Determinants of corporate adaptation to climate change in winter tourism: An econometric analysis     

Volker H. Hoffmann  David C. Sprengel  Andreas Ziegler  Matthias Kolb  Bruno Abegg 《Global Environmental Change》2009,19(2):256-264

While corporate adaptation strategies in response to climate change have been characterized, the determinants of adaptation have not been comprehensively analyzed. Knowledge of these determinants is particularly useful for policy makers to provide favorable conditions in support of corporate adaptation measures. Based on unique data from a survey of Swiss ski lift operators, this paper empirically examines such determinants at the business level. Our econometric analysis with linear regression and count data models finds a positive influence of the awareness of possible climate change effects on the scope of corporate adaptation. Surprisingly, no significant influence of the vulnerability to climate change effects on the scope of adaptation could be found. Finally, the dependency on the affected business and the ability to adapt influence the specific strategic directions of corporate adaptation.  相似文献   

Coral Patch and Ormonde seamounts as a product of the Madeira hotspot,Eastern Atlantic Ocean     

Filippo D'Oriano  Lorenzo Angeletti  Lucilla Capotondi  Marinella A. Laurenzi  Matthias López Correa  Marco Taviani  Luigi Torelli  Teresa Trua  Luigi Vigliotti  Nevio Zitellini 《地学学报》2010,22(6):494-500

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A GIS-BASED GLACIER INVENTORY FOR THE ANTARCTIC PENINSULA AND THE SOUTH SHETLAND ISLANDS——A FIRST CASE STUDY ON KING GEORGE ISLAND   总被引：1，自引：0，他引：1  

Matthias Braun  F.Rau  Jefferson Cardia Si“非汉字字符”mes 《地球空间信息科学学报》2001,4(2)

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Assessing parameter identifiability for multiple performance criteria to constrain model parameters     

Björn Guse  Jens Kiesel  Matthias Pfannerstill  Nicola Fohrer 《水文科学杂志》2020,65(7):1158-1172

ABSTRACT

Reliable simulations of hydrological models require that model parameters are precisely identified. In constraining model parameters to small ranges, high parameter identifiability is achieved. In this study, it is investigated how precisely model parameters can be constrained in relation to a set of contrasting performance criteria. For this, model simulations with identical parameter samplings are carried out with a hydrological model (SWAT) applied to three contrasting catchments in Germany (lowland, mid-range mountains, alpine regions). Ten performance criteria including statistical metrics and signature measures are calculated for each model simulation. Based on the parameter identifiability that is computed separately for each performance criterion, model parameters are constrained to smaller ranges individually for each catchment. An iterative repetition of model simulations with successively constrained parameter ranges leads to more precise parameter identifiability and improves model performance. Based on these results, a more consistent handling of model parameters is achieved for model calibration.  相似文献   

Finite-element modelling of pull-apart basin formation   总被引：1，自引：0，他引：1  

Matthias G  lke  Sierd Cloetingh  Karl Fuchs 《Tectonophysics》1994,240(1-4):45-57

We present the results of a finite-element modelling study of pull-apart basin formation related to left-stepping left lateral strike-slip faults. The modelling quantifies the relationship between fault geometry (i.e., fault overlap and separation) and pull-apart basin formation. Two depocentres (subbasins) separated by a broad zone of relative uplift in between may develop if the strike-slip domain is characterized by fault underlap. For overlapping faults migration of the subbasins is predicted by the models. Deep subbasins in a large area of subsidence which spans the entire inner fault zone may form if fault overlap is about three times the fault separation.

The models suggest that a topographic asymmetry within the fault zone may arise due to a different displacement ratio of the strike-slip faults. The modelling results show that this asymmetry in topography becomes more pronounced towards the more active fault. Thus, basin deepening occurs progressively towards the fault characterized by the largest amount of lateral displacement. Moreover, the results indicate that the smaller the fault separation (less than basin length) the less pronounced the topographic asymmetry.

The models provide quantitative estimates for the effects of changes in elastic material properties, the magnitude of the compressive far-field stress and the coefficient of friction of the faults on the resulting topography.

Comparison of the modelling results with field observations from the Cerro Blanco-El Barranquete (CBB) subbasin located in the Internal Zone of the Betic Cordillera, southeastern Spain support an interpretation in which the interplay of major faults has formed the CBB subbasin.  相似文献   

Coastal upwelling systems and Eastern boundary currents: A review of terminology     

Matthias Tomczak 《Geoforum》1981,12(2):179-191

The use of terms such as Benguela Current or Peru Current System for different features of the oceanic circulation in the eastern parts of the oceans is reviewed. During 50 years of upwelling research these terms have been used for different oceanographic phenomena. It is argued that one reason for inconsistent use has been that names of currents were chosen on geographic rather than hydrodynamic principles, and that although knowledge of the dynamics of current systems expanded, it became increasingly difficult to modify the existing nomenclature accordingly. In order to provide a basis for a unified terminology, the dynamics of ocean currents in the eastern pans of the oceans are reviewed. It is argued that the coastal upwelling current system is a modification of the inshore part of the eastern boundary current and consequently should not be named as opposed to it but as part of it. It is suggested that the traditional geographic names be used for the eastern boundary currents and new names be assigned by international agreement to the coastal upwelling currents.  相似文献