67 research outputs found
Berends_etal_2019_Geosciences_Supplement
No full text<p>Supplement to the Berends et al. (2019) article in Geosciences.<br>
Results from three separate simulations of the last 3.6 Myr with an ice-sheet model: global mean sea-level and pCO2.<br>
Full citation: Berends, C.J., de Boer, B. and van de Wal, R. S. W.: Reconstructing the<br>
evolution of ice sheets, sea-level and atmospheric CO2 during the past 3.6 million years,<br>
Geosciences, special issue “Developments in Modelling Palaeo-Ice Sheets”, 2019 (under review)</p>
Berends_etal_2020_CP_Supplement
No full textSupplement to Berends, C. J., de Boer, B., and van de Wal, R. S. W.: Reconstructing the Evolution of Ice Sheets, Sea Level and Atmospheric CO2 During the Past 3.6 Million Years, Clim. Past Discuss., https://doi.org/10.5194/cp-2020-52, in review, 2020.
Results from three separate simulations of the last 3.6 Myr with the hybrid ice-sheet - climate model
3D noise simulation: Final report of the 2020 synthesis project
No full textNoise simulations require finding the paths between multiple receiver and source points. In the current approach, only 3D polylines can be used as input to describe the terrain. These 3D polylines are semi-automatically generated, based on the principle of describing the terrain profile with as few height lines as possible. In order to propose a more efficient, standardised and economic modelling approach, a partnership between RIVM/RWS and the 3D Geoinformation Group at TU Delft was launched in 2017, aiming to generate these height lines automatically from the available datasets, namely AHN3, BAG, and BGT, which are publicly available via PDOK for free. However, it was then proposed to prove that the paths between receiver and source points can be directly generated from a TIN without creating the height lines. The following report provides proof of concept to the hypothesis: ‘Using a TIN directly allows automated 3D noise modelling according to the guidelines of CNOSSOS-EU’. A code was written to generate the paths between receiver and source points using an LoD2 TIN. The paths were then checked visually and were fed to test_Cnossos software to prove their validity. Finally, noise maps were generated and compared to noise maps generated with the current method.3D noiseGeomatic
Berends_etal_2019_PP_Supplement
No full textThe reconstructed global mean sea-level and atmospheric CO2 concentration over the past 3.6 Myr as published in Berends et al., 2019 (like 2020, after review).</p
Return to sender: Constantijn Huygens as a man of letters
No full textReturn to Sender takes as its starting point Constantijn Huygens’ letters and shows us the author in his different guises: intimus of René Descartes, translator of John Donne, collector of art, writer of flirtatious love letters and the author of a long consolatory letter-poem for an ailing friend who threatened to go blind. In his letters, Huygens emerges as an often playful yet always ambitious fashioner of his own social image. Return to Sender gives us Huygens as ‘a man of letters’ in a very literal way: conceiving and construing his texts with an addressee in mind, but also with the distinct intention to fashion for that reader a persona that could be represented by means of the text at hand
IMAU-ICE v2.0 archive
No full textThe complete model code of IMAU-ICE v2.0, as described in Berends et al. (submitted to Geoscientific Model Development, 2021). Includes makefiles, compilation scripts, run scripts, config files for all the experiments described in the paper, and MATLAB scripts for creating the plots in the paper
Berends_etal_2019_GMD_supplement
No full text<p>Selected results from the Pliocene simulations by Berends et al., 2019: the reconstructed records of pCO<sub>2</sub>, global mean sea level and benthic d<sup>18</sup>O, as well as NetCDF files containing ice thickness, bedrock topography and annual mean surface temperature and precipitation for all four ice-sheet model regions during MIS M2, MIS KM5c and MIS KM3.</p>
Interactions and feedbacks between ice sheets, climate, sea level and the solid Earth
No full textAnthropogenic climate change is one of the largest challenges facing society today. Although mitigating the magnitude of climate change by reducing CO2 emissions is of vital importance, even the most optimistic of future scenarios will still result in significant warming. One of the inevitable consequences of the warming is sea-level rise due to the melting of land ice and the thermal expansion of the. In order to determine an adaptation and mitigation strategy, accurate projections of sea-level rise are required. The vast size of the large ice sheets on Greenland and Antarctica lead to a slow response to a change in climate: it takes years to decades before a change in climate even begins to significantly affect ice sheet growth or retreat, and hundreds to thousands of years to reach a new equilibrium. This implies that observational alone is insufficient to predict future ice-sheet evolution. To overcome this problem, palaeoglaciology, the study of the past behaviour of glaciers and ice sheets, is helpful. In the geological past, Earth’s climate has undergone major changes, some even larger than the ongoing present anthropogenic change, though probably not quite as fast. Often these climate changes, in particular the glacial cycles of the Pleistocene, were accompanied by large changes in ice-sheet size, and therefore sea level. By studying the relation between the climate and the ice sheets in the past, and trying to reproduce their evolution with models, we contribute to the understanding of the Earth system, and the response of ice sheets in the future.
A complication that is implicit in palaeoglaciology more than in future projections, is that the interaction between ice sheets and climate works in two directions. Changes in temperature and precipitation patterns will affect how much snow accumulates and melts on an ice sheet. However, changes in ice extent and geometry also affect local temperatures through changes in surface albedo and altitude, and in addition affect precipitation through orographic forcing and changes in large-scale atmospheric circulation. Changes in ocean temperatures affect the melting of floating ice, but the addition of large amounts of fresh melt water to the ocean can affect ocean currents.
As a consequence, a change in any part of the Earth system will directly or indirectly affect all the other parts. Throughout Earth’s geological past, all the different components changed in concert, continuously affecting each other through coupling effects and the associated feedback processes. Any model that aims to successfully simulate the behaviour of one or more components will therefore need to include an accurate representation of the interactions and feedback processes in the Earth system.
This thesis aims to incorporate several of these feedback processes into an existing ice- sheet model, and use that model configuration to reproduce the behaviour of ice-sheets during different episodes during the past several million years
Idealised steady-state and transient simulations of Miocene Antarctic ice-sheet variability using 3D thermodynamical ice-sheet model IMAU-ICE
No full textWe present results from simulations of the Miocene Antarctic ice sheet, that were performed using the 3D thermodynamical ice-sheet model IMAU-ICE (v1.1.1-MIO). Five steady-state present-day simulations were conducted for reference (PI_ref), and 12 experiments using Miocene settings. Each Miocene experiment comprises 11 steady-state and 4 transient simulations. In the README file, the experiments and simulations are listed.
IMAU-ICE was run using a 40x40km grid covering the Antarctic continent. Initial conditions were obtained from reconstructions of the Antarctic bathymetry and bedrock topography pertaining to 23 to 24 million years (Myr) ago (dataset doi:10.1594/PANGAEA.923109). The simulations were forced by climate input data obtained from GENESIS simulations with varying CO2 levels (280 to 840 ppm) and Antarctic ice sheet cover (no ice to a large East-Antarctic ice sheet), and with present-day insolation. We utilized a matrix interpolation method to construct the time-varying climate forcing, based on the prescribed CO2 levels and ice cover simulated by IMAU-ICE.
For each simulation, we provide the run script, 1D output variables including CO2 level and the sea level contribution of the Antarctic ice sheet, and 3D output variables including ice thickness, bedrock and surface height, surface mass balance, basal mass balance, ice velocities, and ice temperatures. For more information, please contact L.B. Stap at [email protected]
Berends_etal_2018_GMD_code
No full text<p>Source code of the ANICE2.1 ice-sheet-shelf model. For more information, please contact the main author at [email protected].</p>
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