ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A thermomechanical model of ice flow in West Antarctica (1999)
    Springer
    Climate dynamics 15 (1999), S. 115-125 
    Details
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract  This study uses a three-dimensional thermo-mechanical model to investigate the internal flow dynamics of the West Antarctic Ice Sheet (WAIS). The model allows ice thickness, flow and temperature to interact freely. Its domain is prescribed as that of the present-day grounded WAIS. Realistic present-day climatic and topographical boundary conditions are employed. The analysis of a series of experiments pays particular attention to the location and dynamics of concentrations of ice flow (ice streams). Underlying topographic troughs are crucial in determining the strength and location of these concentrations of flow. The flow pattern generated by subglacial troughs is made more distinct by the inclusion of ice flow/temperature coupling. The inclusion of sliding leads to the generation of limit cycles in the ice flow. They are concentrated around the present-day ice streams B and C of the Siple Coast and have a period of 5 to 10 ky. There appears to be competition between several preferred ice flow pathways in this area. The two end members of the flow regime are a strong ice stream C with a weakened ice stream A/B complex, and strong ice streams A and B with a dormant ice stream C. Ice streams appear to require ice discharges above a certain threshold in order to maintain frictional heat generation and fast flow. Individual ice streams can therefore interact through changes in catchment-area size: a reduction in catchment area reduces the volume of ice entering a stream and can cause stagnation as the amount of frictional heating falls.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003820050271
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Preparation and phase studies of the ternary semiconducting compounds ZnSnP2, ZnGeP2, ZnSiP2, CdGeP2, and CdSiP2 (1969)
    Springer
    Journal of materials science 4 (1969), S. 895-901 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract ZnSnP2, ZnGeP2, ZnSiP2, CdGeP2 and CdSiP2 have been prepared in single or polycrystalline form by direct synthesis from the elements, combination of the group IV element with the II-V2 phosphide, vapour transport or solution growth. Differential thermal analysis and X-ray powder diffraction studies have been used to determine the temperatures of phase transitions in each of these compounds. Of particular interest is the observation of a phase transition in CdSiP2 at 1098° C some 22° C below the melting point. The thermal analysis studies of ZnSnP2 indicate a peak, the cause of which is uncertain, at 720° C which is well separated from the melting temperature of 930° C; further ZnSnP2 does not appear to be congruently melting and has a freezing point at 970° C. c/a ratios have been determined for all five compounds to 1 part in 2000.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00549781
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A Bernoulli Cell-Based Investigation of the Non-Linear Dynamics in Log-Domain Structures (2000)
    Springer
    Analog integrated circuits and signal processing 22 (2000), S. 127-146 
    Details
    ISSN: 1573-1979
    Keywords: log-domain circuits ; active filters ; analog integrated circuits ; circuit theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper presents a low-level treatment of the non-linear dynamics encountered in log-domain structures, by means of a non-linear circuit element termed a Bernoulli Cell. This cell comprises an npn BJT and an emitter-connected grounded capacitor, and its dynamic behavior is determined by a differential equation of the Bernoulli form. The identification of the Bernoulli Cell leads to the creation of a system of linear differential equations which describe the dynamics of the derived log-domain state-variables. Furthermore, it is shown that the Bernoulli Cell has a memristive type dynamic behavior. The approach aids the analysis of log-domain circuits, and allows the internal non-linear currents to be conveniently expressed in closed analytical form. A worked example for a specific topology with confirming simulation results in both frequency and time-domain is presented. The celebrated Hodgkin-Huxley nerve axon membrane dynamics are also successfully simulated as a characteristic example of memristive behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008317708347
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    facet.materialart.
    Unknown
    Century-scale simulations of the response of the West Antarctic Ice Sheet to a warming climate (2015)
    In:  EPIC3The Cryosphere, 9(4), pp. 1579-1600, ISSN: 1994-0424
    Details
    Publication Date: 2015-09-28
    Description: We use the BISICLES adaptive mesh ice sheet model to carry out one, two, and three century simulations of the fast-flowing ice streams of the West Antarctic Ice Sheet, deploying sub-kilometer resolution around the grounding line since coarser resolution results in substantial underestimation of the response. Each of the simulations begins with a geometry and velocity close to present-day observations, and evolves according to variation in meteoric ice accumulation rates and oceanic ice shelf melt rates. Future changes in accumulation and melt rates range from no change, through anomalies computed by atmosphere and ocean models driven by the E1 and A1B emissions scenarios, to spatially uniform melt rate anomalies that remove most of the ice shelves over a few centuries. We find that variation in the resulting ice dynamics is dominated by the choice of initial conditions and ice shelf melt rate and mesh resolution, although ice accumulation affects the net change in volume above flotation to a similar degree. Given sufficient melt rates, we compute grounding line retreat over hundreds of kilometers in every major ice stream, but the ocean models do not predict such melt rates outside of the Amundsen Sea Embayment until after 2100. Within the Amundsen Sea Embayment the largest single source of variability is the onset of sustained retreat in Thwaites Glacier, which can triple the rate of eustatic sea level rise.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 5
    facet.materialart.
    Unknown
    Results from the EISMINT model intercomparison: the effects of thermomechanical coupling (2000)
    In:  EPIC3Journal of Glaciology, 46(153), pp. 227-238
    Details
    Publication Date: 2019-07-17
    Description: This paper discusses results from the second phase of the European Ice sheet Modelling Initiative (EISMINT). It reports the intercompartison of ten operational ice-sheet models and uses a series of experiments to examine the implications of thermomechanical coupling for model behaviour. A schematic, circular ice sheet is used in the work which investigates both steady states and the response to stepped changes in climate. The major finding is that radial symmetry implied in the experimental design can, under certain circumstances, break down with the formation of distinct, regularly spaced spokes of cold ice which extended from the interior of the ice sheet outward to the surrounding zone of basal melt. These features also manifest themselves in the thickness and velocity distributions predicted by the models. They appear to be a common feature to all of the models which took part in the intercomparison, and may stem from interactions between ice temperature, flow and surface form. The exact nature of these features varies between models, and their existence appears to be controlled by the overall thermal regimne of the ice sheet. A second result is that there is considerable agreement between the models in their predictions of global-scale response to imposed climate change.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    Projecting Antarctic ice discharge using response functions from SeaRISE ice-sheet models (2012)
    In:  EPIC3The Cryosphere Discussions, 6(4), pp. 3447-3489, ISSN: 1994-0440
    Details
    Publication Date: 2019-07-17
    Description: The largest uncertainty in projections of future sea-level change still results from the potentially changing dynamical ice discharge from Antarctica. While ice discharge can alter through a number of processes, basal ice-shelf melting induced by a warming ocean has been identified as a major if not the major cause for possible additional ice flow across the grounding line. Here we derive dynamic ice-sheet response functions for basal ice-shelf melting using experiments carried out within the Sea-level Response to Ice Sheet Evolution (SeaRISE) intercomparison project with five different Antarctic ice-sheet models. As used here these response functions provide separate contributions for four different Antarctic drainage regions. Under the assumptions of linear-response theory we project future ice-discharge for each model, each region and each of the four Representative Concentration Pathways (RCP) using oceanic temperatures from 19 comprehensive climate models of the Coupled Model Intercomparison Project, CMIP-5, and two ocean models from the EU-project Ice2Sea. Uncertainty in the climatic forcing, the oceanic response and the ice-model differences is combined into an uncertainty range of future Antarctic ice-discharge induced from basal ice-shelf melt. The additional ice-loss (Table 6) is clearly scenario-dependent and results in a median of 0.07 m (66%-range: 0.04–0.10 m; 90%-range: −0.01–0.26 m) of global sea-level equivalent for the low-emission RCP-2.6 scenario and yields 0.1 m (66%-range: 0.06–0.14 m; 90%-range: −0.01–0.45 m) for the strongest RCP-8.5. If only models with an explicit representation of ice-shelves are taken into account the scenario dependence remains and the values change to: 0.05 m (66%-range: 0.03–0.08 m) for RCP-2.6 and 0.07 m (66%-range: 0.04–0.11 m) for RCP-8.5. These results were obtained using a time delay between the surface warming signal and the subsurface oceanic warming as observed in the CMIP-5 models. Without this time delay the ranges for all ice-models changes to 0.10 m (66%-range: 0.07–0.12 m; 90%-range: 0.01–0.28 m) for RCP-2.6 and 0.15 m (66%-range: 0.10–0.21 m; 90%-range: 0.02–0.53 m) for RCP-8.5. All probability distributions as provided in Fig. 10 are highly skewed towards high values.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    Projecting Antarctic ice discharge using response functions from SeaRISE ice-sheet models (2014)
    Copernicus Publications
    In:  EPIC3Earth System Dynamics, Copernicus Publications, 5(2), pp. 271-293, ISSN: 2190-4987
    Details
    Publication Date: 2014-09-17
    Description: The largest uncertainty in projections of future sea-level change results from the potentially changing dynamical ice discharge from Antarctica. Basal ice-shelf melting induced by a warming ocean has been identified as a major cause for additional ice flow across the grounding line. Here we attempt to estimate the uncertainty range of future ice discharge from Antarctica by combining uncertainty in the climatic forcing, the oceanic response and the ice-sheet model response. The uncertainty in the global mean temperature increase is obtained from historically constrained emulations with the MAGICC-6.0 (Model for the Assessment of Greenhouse gas Induced Climate Change) model. The oceanic forcing is derived from scaling of the subsurface with the atmospheric warming from 19 comprehensive climate models of the Coupled Model Intercomparison Project (CMIP-5) and two ocean models from the EU-project Ice2Sea. The dynamic ice-sheet response is derived from linear response functions for basal ice-shelf melting for four different Antarctic drainage regions using experiments from the Sea-level Response to Ice Sheet Evolution (SeaRISE) intercomparison project with five different Antarctic ice-sheet models. The resulting uncertainty range for the historic Antarctic contribution to global sea-level rise from 1992 to 2011 agrees with the observed contribution for this period if we use the three ice-sheet models with an explicit representation of ice-shelf dynamics and account for the time-delayed warming of the oceanic subsurface compared to the surface air temperature. The median of the additional ice loss for the 21st century is computed to 0.07 m (66% range: 0.02–0.14 m; 90% range: 0.0–0.23 m) of global sea-level equivalent for the low-emission RCP-2.6 (Representative Concentration Pathway) scenario and 0.09 m (66% range: 0.04–0.21 m; 90% range: 0.01–0.37 m) for the strongest RCP-8.5. Assuming no time delay between the atmospheric warming and the oceanic subsurface, these values increase to 0.09 m (66% range: 0.04–0.17 m; 90% range: 0.02–0.25 m) for RCP-2.6 and 0.15 m (66% range: 0.07–0.28 m; 90% range: 0.04–0.43 m) for RCP-8.5. All probability distributions are highly skewed towards high values. The applied ice-sheet models are coarse resolution with limitations in the representation of grounding-line motion. Within the constraints of the applied methods, the uncertainty induced from different ice-sheet models is smaller than that induced by the external forcing to the ice sheets.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 8
    facet.materialart.
    Unknown
    The human imperative of stabilizing global climate change at 1.5°C (2019)
    In:  EPIC3Science, 365(6459), pp. eaaw6974, ISSN: 0036-8075
    Details
    Publication Date: 2020-03-28
    Description: Increased concentrations of atmospheric greenhouse gases have led to a global mean surface temperature 1.0°C higher than during the pre-industrial period. We expand on the recent IPCC Special Report on global warming of 1.5°C and review the additional risks associated with higher levels of warming, each having major implications for multiple geographies, climates, and ecosystems. Limiting warming to 1.5°C rather than 2.0°C would be required to maintain substantial proportions of ecosystems and would have clear benefits for human health and economies. These conclusions are relevant for people everywhere, particularly in low- and middle-income countries, where the escalation of climate-related risks may prevent the achievement of the United Nations Sustainable Development Goals. Copyright © 2019 The Authors,
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    Committed sea-level rise for the next century from Greenland ice sheet dynamics during the past decade (2011)
    National Academy of Sciences
    Details
    Publication Date: 2011-05-16
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Enhanced basal lubrication and the contribution of the Greenland ice sheet to future sea-level rise (2013)
    National Academy of Sciences
    Details
    Publication Date: 2013-08-12
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...