@misc{Bilgen2024,
author = {Bilgen, Isa},
title = {Unsere W{\"u}rde in Euren H{\"a}nden},
series = {Verfassungsblog : on matters constitutional},
journal = {Verfassungsblog : on matters constitutional},
publisher = {Max Steinbeis Verfassungsblog gGmbH},
address = {Berlin},
issn = {2366-7044},
doi = {10.17176/20240204-004217-0},
pages = {9},
year = {2024},
language = {de}
}
@article{SeroussiNowickiSimonetal.2019,
author = {Seroussi, Helene and Nowicki, Sophie and Simon, Erika and Abe-Ouchi, Ayako and Albrecht, Torsten and Brondex, Julien and Cornford, Stephen and Dumas, Christophe and Gillet-Chaulet, Fabien and Goelzer, Heiko and Golledge, Nicholas R. and Gregory, Jonathan M. and Greve, Ralf and Hoffman, Matthew J. and Humbert, Angelika and Huybrechts, Philippe and Kleiner, Thomas and Larourl, Eric and Leguy, Gunter and Lipscomb, William H. and Lowry, Daniel and Mengel, Matthias and Morlighem, Mathieu and Pattyn, Frank and Payne, Anthony J. and Pollard, David and Price, Stephen F. and Quiquet, Aurelien and Reerink, Thomas J. and Reese, Ronja and Rodehacke, Christian B. and Schlegel, Nicole-Jeanne and Shepherd, Andrew and Sun, Sainan and Sutter, Johannes and Van Breedam, Jonas and van de Wal, Roderik S. W. and Winkelmann, Ricarda and Zhang, Tong},
title = {initMIP-Antarctica},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {13},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {5},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1994-0416},
doi = {10.5194/tc-13-1441-2019},
pages = {1441 -- 1471},
year = {2019},
abstract = {Ice sheet numerical modeling is an important tool to estimate the dynamic contribution of the Antarctic ice sheet to sea level rise over the coming centuries. The influence of initial conditions on ice sheet model simulations, however, is still unclear. To better understand this influence, an initial state intercomparison exercise (initMIP) has been developed to compare, evaluate, and improve initialization procedures and estimate their impact on century-scale simulations. initMlP is the first set of experiments of the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6), which is the primary Coupled Model Intercomparison Project Phase 6 (CMIP6) activity focusing on the Greenland and Antarctic ice sheets. Following initMlP-Greenland, initMlP-Antarctica has been designed to explore uncertainties associated with model initialization and spin-up and to evaluate the impact of changes in external forcings. Starting from the state of the Antarctic ice sheet at the end of the initialization procedure, three forward experiments are each run for 100 years: a control run, a run with a surface mass balance anomaly, and a run with a basal melting anomaly beneath floating ice. This study presents the results of initMlP-Antarctica from 25 simulations performed by 16 international modeling groups. The submitted results use different initial conditions and initialization methods, as well as ice flow model parameters and reference external forcings. We find a good agreement among model responses to the surface mass balance anomaly but large variations in responses to the basal melting anomaly. These variations can be attributed to differences in the extent of ice shelves and their upstream tributaries, the numerical treatment of grounding line, and the initial ocean conditions applied, suggesting that ongoing efforts to better represent ice shelves in continental-scale models should continue.},
language = {en}
}
@article{ReeseAlbrechtMengeletal.2018,
author = {Reese, Ronja and Albrecht, Torsten and Mengel, Matthias and Asay-Davis, Xylar and Winkelmann, Ricarda},
title = {Antarctic sub-shelf melt rates via PICO},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {12},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {6},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1994-0416},
doi = {10.5194/tc-12-1969-2018},
pages = {1969 -- 1985},
year = {2018},
abstract = {Ocean-induced melting below ice shelves is one of the dominant drivers for mass loss from the Antarctic Ice Sheet at present. An appropriate representation of sub-shelf melt rates is therefore essential for model simulations of marine-based ice sheet evolution. Continental-scale ice sheet models often rely on simple melt-parameterizations, in particular for long-term simulations, when fully coupled ice-ocean interaction becomes computationally too expensive. Such parameterizations can account for the influence of the local depth of the ice-shelf draft or its slope on melting. However, they do not capture the effect of ocean circulation underneath the ice shelf. Here we present the Potsdam Ice-shelf Cavity mOdel (PICO), which simulates the vertical overturning circulation in ice-shelf cavities and thus enables the computation of sub-shelf melt rates consistent with this circulation. PICO is based on an ocean box model that coarsely resolves ice shelf cavities and uses a boundary layer melt formulation. We implement it as a module of the Parallel Ice Sheet Model (PISM) and evaluate its performance under present-day conditions of the Southern Ocean. We identify a set of parameters that yield two-dimensional melt rate fields that qualitatively reproduce the typical pattern of comparably high melting near the grounding line and lower melting or refreezing towards the calving front. PICO captures the wide range of melt rates observed for Antarctic ice shelves, with an average of about 0.1 ma(-1) for cold sub-shelf cavities, for example, underneath Ross or Ronne ice shelves, to 16 ma(-1) for warm cavities such as in the Amundsen Sea region. This makes PICO a computationally feasible and more physical alternative to melt parameterizations purely based on ice draft geometry.},
language = {en}
}
@article{ReeseWinkelmannGudmundsson2018,
author = {Reese, Ronja and Winkelmann, Ricarda and Gudmundsson, Gudmundur Hilmar},
title = {Grounding-line flux formula applied as a flux condition in numerical simulations fails for buttressed Antarctic ice streams},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {12},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {10},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1994-0416},
doi = {10.5194/tc-12-3229-2018},
pages = {3229 -- 3242},
year = {2018},
abstract = {Currently, several large-scale ice-flow models impose a condition on ice flux across grounding lines using an analytically motivated parameterisation of grounding-line flux. It has been suggested that employing this analytical expression alleviates the need for highly resolved computational domains around grounding lines of marine ice sheets. While the analytical flux formula is expected to be accurate in an unbuttressed flow-line setting, its validity has hitherto not been assessed for complex and realistic geometries such as those of the Antarctic Ice Sheet. Here the accuracy of this analytical flux formula is tested against an optimised ice flow model that uses a highly resolved computational mesh around the Antarctic grounding lines. We find that when applied to the Antarctic Ice Sheet the analytical expression provides inaccurate estimates of ice fluxes for almost all grounding lines. Furthermore, in many instances direct application of the analytical formula gives rise to unphysical complex-valued ice fluxes. We conclude that grounding lines of the Antarctic Ice Sheet are, in general, too highly buttressed for the analytical parameterisation to be of practical value for the calculation of grounding-line fluxes.},
language = {en}
}
@article{AlbrechtWinkelmannLevermann2020,
author = {Albrecht, Torsten and Winkelmann, Ricarda and Levermann, Anders},
title = {Glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM)},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {14},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {2},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1994-0416},
doi = {10.5194/tc-14-599-2020},
pages = {599 -- 632},
year = {2020},
abstract = {Simulations of the glacial-interglacial history of the Antarctic Ice Sheet provide insights into dynamic threshold behavior and estimates of the ice sheet's contributions to global sea-level changes for the past, present and future. However, boundary conditions are weakly constrained, in particular at the interface of the ice sheet and the bedrock. Also climatic forcing covering the last glacial cycles is uncertain, as it is based on sparse proxy data.
We use the Parallel Ice Sheet Model (PISM) to investigate the dynamic effects of different choices of input data, e.g., for modern basal heat flux or reconstructions of past changes of sea level and surface temperature. As computational resources are limited, glacial-cycle simulations are performed using a comparably coarse model grid of 16 km and various parameterizations, e.g., for basal sliding, iceberg calving, or for past variations in precipitation and ocean temperatures. In this study we evaluate the model's transient sensitivity to corresponding parameter choices and to different boundary conditions over the last two glacial cycles and provide estimates of involved uncertainties. We also discuss isolated and combined effects of climate and sea-level forcing. Hence, this study serves as a "cookbook" for the growing community of PISM users and paleo-ice sheet modelers in general.
For each of the different model uncertainties with regard to climatic forcing, ice and Earth dynamics, and basal processes, we select one representative model parameter that captures relevant uncertainties and motivates corresponding parameter ranges that bound the observed ice volume at present. The four selected parameters are systematically varied in a parameter ensemble analysis, which is described in a companion paper.},
language = {en}
}
@article{KreuzerReeseHuiskampetal.2021,
author = {Kreuzer, Moritz and Reese, Ronja and Huiskamp, Willem Nicholas and Petri, Stefan and Albrecht, Torsten and Feulner, Georg and Winkelmann, Ricarda},
title = {Coupling framework (1.0) for the PISM (1.1.4) ice sheet model and the MOMS (5.1.0) ocean model via the PICO ice shelf cavity model in an Antarctic domain},
series = {Geoscientific model development : an interactive open access journal of the European Geosciences Union},
volume = {14},
journal = {Geoscientific model development : an interactive open access journal of the European Geosciences Union},
number = {6},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1991-959X},
doi = {10.5194/gmd-14-3697-2021},
pages = {3697 -- 3714},
year = {2021},
abstract = {The past and future evolution of the Antarctic Ice Sheet is largely controlled by interactions between the ocean and floating ice shelves. To investigate these interactions, coupled ocean and ice sheet model configurations are required. Previous modelling studies have mostly relied on high-resolution configurations, limiting these studies to individual glaciers or regions over short timescales of decades to a few centuries. We present a framework to couple the dynamic ice sheet model PISM (Parallel Ice Sheet Model) with the global ocean general circulation model MOM5 (Modular Ocean Model) via the ice shelf cavity model PICO (Pots-dam Ice-shelf Cavity mOdel). As ice shelf cavities are not resolved by MOM5 but are parameterized with the PICO box model, the framework allows the ice sheet and ocean components to be run at resolutions of 16 km and 3 degrees respectively. This approach makes the coupled configuration a useful tool for the analysis of interactions between the Antarctic Ice Sheet and the global ocean over time spans of the order of centuries to millennia. In this study, we describe the technical implementation of this coupling framework: sub-shelf melting in the ice sheet component is calculated by PICO from modelled ocean temperatures and salinities at the depth of the continental shelf, and, vice versa, the resulting mass and energy fluxes from melting at the ice-ocean interface are transferred to the ocean component. Mass and energy fluxes are shown to be conserved to machine precision across the considered component domains. The implementation is computationally efficient as it introduces only minimal overhead. Furthermore, the coupled model is evaluated in a 4000 year simulation under constant present-day climate forcing and is found to be stable with respect to the ocean and ice sheet spin-up states. The framework deals with heterogeneous spatial grid geometries, varying grid resolutions, and timescales between the ice and ocean component in a generic way; thus, it can be adopted to a wide range of model set-ups.},
language = {en}
}
@article{ZeitzHaackerDongesetal.2022,
author = {Zeitz, Maria and Haacker, Jan M. and Donges, Jonathan and Albrecht, Torsten and Winkelmann, Ricarda},
title = {Dynamic regimes of the Greenland Ice Sheet emerging from interacting melt-elevation and glacial isostatic adjustment feedbacks},
series = {Earth system dynamics},
volume = {13},
journal = {Earth system dynamics},
number = {3},
publisher = {Copernicus Publ.},
address = {G{\"o}ttingen},
issn = {2190-4979},
doi = {10.5194/esd-13-1077-2022},
pages = {1077 -- 1096},
year = {2022},
abstract = {The stability of the Greenland Ice Sheet under global warming is governed by a number of dynamic processes and interacting feedback mechanisms in the ice sheet, atmosphere and solid Earth. Here we study the long-term effects due to the interplay of the competing melt-elevation and glacial isostatic adjustment (GIA) feedbacks for different temperature step forcing experiments with a coupled ice-sheet and solid-Earth model. Our model results show that for warming levels above 2 degrees C, Greenland could become essentially ice-free within several millennia, mainly as a result of surface melting and acceleration of ice flow. These ice losses are mitigated, however, in some cases with strong GIA feedback even promoting an incomplete recovery of the Greenland ice volume. We further explore the full-factorial parameter space determining the relative strengths of the two feedbacks: our findings suggest distinct dynamic regimes of the Greenland Ice Sheets on the route to destabilization under global warming - from incomplete recovery, via quasi-periodic oscillations in ice volume to ice-sheet collapse. In the incomplete recovery regime, the initial ice loss due to warming is essentially reversed within 50 000 years, and the ice volume stabilizes at 61 \%-93 \% of the present-day volume. For certain combinations of temperature increase, atmospheric lapse rate and mantle viscosity, the interaction of the GIA feedback and the melt-elevation feedback leads to self-sustained, long-term oscillations in ice-sheet volume with oscillation periods between 74 000 and over 300 000 years and oscillation amplitudes between 15 \%-70 \% of present-day ice volume. This oscillatory regime reveals a possible mode of internal climatic variability in the Earth system on timescales on the order of 100 000 years that may be excited by or synchronized with orbital forcing or interact with glacial cycles and other slow modes of variability. Our findings are not meant as scenario-based near-term projections of ice losses but rather providing insight into of the feedback loops governing the "deep future" and, thus, long-term resilience of the Greenland Ice Sheet.},
language = {en}
}
@article{AlbrechtWinkelmannLevermann2020,
author = {Albrecht, Torsten and Winkelmann, Ricarda and Levermann, Anders},
title = {Glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM)},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {14},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {2},
publisher = {Copernicus Publ.},
address = {G{\"o}ttingen},
issn = {1994-0416},
doi = {10.5194/tc-14-633-2020},
pages = {633 -- 656},
year = {2020},
abstract = {The Parallel Ice Sheet Model (PISM) is applied to the Antarctic Ice Sheet over the last two glacial cycles (approximate to 210 000 years) with a resolution of 16 km. An ensemble of 256 model runs is analyzed in which four relevant model parameters have been systematically varied using full-factorial parameter sampling. Parameters and plausible parameter ranges have been identified in a companion paper (Albrecht et al., 2020) and are associated with ice dynamics, climatic forcing, basal sliding and bed deformation and represent distinct classes of model uncertainties. The model is scored against both modern and geologic data, including reconstructed grounding-line locations, elevation-age data, ice thickness, surface velocities and uplift rates. An aggregated score is computed for each ensemble member that measures the overall model-data misfit, including measurement uncertainty in terms of a Gaussian error model (Briggs and Tarasov, 2013). The statistical method used to analyze the ensemble simulation results follows closely the simple averaging method described in Pollard et al. (2016). This analysis reveals clusters of best-fit parameter combinations, and hence a likely range of relevant model and boundary parameters, rather than individual best-fit parameters. The ensemble of reconstructed histories of Antarctic Ice Sheet volumes provides a score-weighted likely range of sea-level contributions since the Last Glacial Maximum (LGM) of 9.4 +/- 4.1m (or 6.5 +/- 2.0 x 10(6) km(3)), which is at the upper range of most previous studies. The last deglaciation occurs in all ensemble simulations after around 12 000 years before present and hence after the meltwater pulse 1A (MWP1a). Our ensemble analysis also provides an estimate of parametric uncertainty bounds for the present-day state that can be used for PISM projections of future sea-level contributions from the Antarctic Ice Sheet.},
language = {en}
}
@article{SchlemmFeldmannWinkelmannetal.2022,
author = {Schlemm, Tanja and Feldmann, Johannes and Winkelmann, Ricarda and Levermann, Anders},
title = {Stabilizing effect of melange buttressing on the marine ice-cliff instability of the West Antarctic Ice Sheet},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {16},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {5},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1994-0416},
doi = {10.5194/tc-16-1979-2022},
pages = {1979 -- 1996},
year = {2022},
abstract = {Owing to global warming and particularly high regional ocean warming, both Thwaites and Pine Island Glaciers in the Amundsen region of the Antarctic Ice Sheet could lose their buttressing ice shelves over time. We analyse the possible consequences using the parallel ice sheet model (PISM), applying a simple cliff-calving parameterization and an ice melange-buttressing model. We find that the instantaneous loss of ice-shelf buttressing, due to enforced ice-shelf melting, initiates grounding-line retreat and triggers marine ice sheet instability (MISI). As a consequence, the grounding line progresses into the interior of the West Antarctic Ice Sheet and leads to a sea level contribution of 0.6 m within 100 a. By subjecting the exposed ice cliffs to cliff calving using our simplified parameterization, we also analyse marine ice cliff instability (MICI). In our simulations it can double or even triple the sea level contribution depending on the only loosely constrained parameter that determines the maximum cliff-calving rate. The speed of MICI depends on this upper bound of the calving rate, which is given by the ice melange buttressing the glacier. However, stabilization of MICI may occur for geometric reasons. Because the embayment geometry changes as MICI advances into the interior of the ice sheet, the upper bound on calving rates is reduced and the progress of MICI is slowed down. Although we cannot claim that our simulations bear relevant quantitative estimates of the effect of ice-melange buttressing on MICI, the mechanism has the potential to stop the instability. Further research is needed to evaluate its role for the past and future evolution of the Antarctic Ice Sheet.},
language = {en}
}
@article{FeldmannReeseWinkelmannetal.2022,
author = {Feldmann, Johannes and Reese, Ronja and Winkelmann, Ricarda and Levermann, Anders},
title = {Shear-margin melting causes stronger transient ice discharge than ice-stream melting in idealized simulations},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {16},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {5},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1994-0416},
doi = {10.5194/tc-16-1927-2022},
pages = {1927 -- 1940},
year = {2022},
abstract = {Basal ice-shelf melting is the key driver of Antarctica's increasing sea-level contribution. In diminishing the buttressing force of the ice shelves that fringe the ice sheet, the melting increases the ice discharge into the ocean. Here we contrast the influence of basal melting in two different ice-shelf regions on the time-dependent response of an isothermal, inherently buttressed ice-sheet-shelf system. In the idealized numerical simulations, the basal-melt perturbations are applied close to the grounding line in the ice-shelf's (1) ice-stream region, where the ice shelf is fed by the fastest ice masses that stream through the upstream bed trough and (2) shear margins, where the ice flow is slower. The results show that melting below one or both of the shear margins can cause a decadal to centennial increase in ice discharge that is more than twice as large compared to a similar perturbation in the ice-stream region. We attribute this to the fact that melt-induced ice-shelf thinning in the central grounding-line region is attenuated very effectively by the fast flow of the central ice stream. In contrast, the much slower ice dynamics in the lateral shear margins of the ice shelf facilitate sustained ice-shelf thinning and thereby foster buttressing reduction. Regardless of the melt location, a higher melt concentration toward the grounding line generally goes along with a stronger response. Our results highlight the vulnerability of outlet glaciers to basal melting in stagnant, buttressing-relevant ice-shelf regions, a mechanism that may gain importance under future global warming.},
language = {en}
}
@article{WunderlingWilleitDongesetal.2020,
author = {Wunderling, Nico and Willeit, Matteo and Donges, Jonathan and Winkelmann, Ricarda},
title = {Global warming due to loss of large ice masses and Arctic summer sea ice},
series = {Nature Communications},
volume = {11},
journal = {Nature Communications},
number = {1},
publisher = {Nature Publishing Group},
address = {Berlin},
issn = {2041-1723},
doi = {10.1038/s41467-020-18934-3},
pages = {14},
year = {2020},
abstract = {Several large-scale cryosphere elements such as the Arctic summer sea ice, the mountain glaciers, the Greenland and West Antarctic Ice Sheet have changed substantially during the last century due to anthropogenic global warming. However, the impacts of their possible future disintegration on global mean temperature (GMT) and climate feedbacks have not yet been comprehensively evaluated. Here, we quantify this response using an Earth system model of intermediate complexity. Overall, we find a median additional global warming of 0.43 degrees C (interquartile range: 0.39-0.46 degrees C) at a CO2 concentration of 400 ppm. Most of this response (55\%) is caused by albedo changes, but lapse rate together with water vapour (30\%) and cloud feedbacks (15\%) also contribute significantly. While a decay of the ice sheets would occur on centennial to millennial time scales, the Arctic might become ice-free during summer within the 21st century. Our findings imply an additional increase of the GMT on intermediate to long time scales. The disintegration of cryosphere elements such as the Arctic summer sea ice, mountain glaciers, Greenland and West Antarctica is associated with temperature and radiative feedbacks. In this work, the authors quantify these feedbacks and find an additional global warming of 0.43 degrees C.},
language = {en}
}
@article{ZeitzReeseBeckmannetal.2021,
author = {Zeitz, Maria and Reese, Ronja and Beckmann, Johanna and Krebs-Kanzow, Uta and Winkelmann, Ricarda},
title = {Impact of the melt-albedo feedback on the future evolution of the Greenland Ice Sheet with PISM-dEBM-simple},
series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
volume = {15},
journal = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
number = {12},
publisher = {Copernicus},
address = {Katlenburg-Lindau},
issn = {1994-0416},
doi = {10.5194/tc-15-5739-2021},
pages = {5739 -- 5764},
year = {2021},
abstract = {Surface melting of the Greenland Ice Sheet contributes a large amount to current and future sea level rise. Increased surface melt may lower the reflectivity of the ice sheet surface and thereby increase melt rates: the so-called melt-albedo feedback describes this self-sustaining increase in surface melting. In order to test the effect of the melt-albedo feedback in a prognostic ice sheet model, we implement dEBM-simple, a simplified version of the diurnal Energy Balance Model dEBM, in the Parallel Ice Sheet Model (PISM). The implementation includes a simple representation of the melt-albedo feedback and can thereby replace the positive-degree-day melt scheme. Using PISM-dEBM-simple, we find that this feedback increases ice loss through surface warming by 60 \% until 2300 for the high-emission scenario RCP8.5 when compared to a scenario in which the albedo remains constant at its present-day values. With an increase of 90 \% compared to a fixed-albedo scenario, the effect is more pronounced for lower surface warming under RCP2.6. Furthermore, assuming an immediate darkening of the ice surface over all summer months, we estimate an upper bound for this effect to be 70 \% in the RCP8.5 scenario and a more than 4-fold increase under RCP2.6. With dEBM-simple implemented in PISM, we find that the melt-albedo feedback is an essential contributor to mass loss in dynamic simulations of the Greenland Ice Sheet under future warming.},
language = {en}
}
@article{KloseWunderlingWinkelmannetal.2021,
author = {Klose, Ann Kristin and Wunderling, Nico and Winkelmann, Ricarda and Donges, Jonathan},
title = {What do we mean, 'tipping cascade'?},
series = {Environmental research letters : ERL},
volume = {16},
journal = {Environmental research letters : ERL},
number = {12},
publisher = {IOP Publ. Ltd.},
address = {Bristol},
issn = {1748-9326},
doi = {10.1088/1748-9326/ac3955},
pages = {11},
year = {2021},
abstract = {Based on suggested interactions of potential tipping elements in the Earth's climate and in ecological systems, tipping cascades as possible dynamics are increasingly discussed and studied. The activation of such tipping cascades would impose a considerable risk for human societies and biosphere integrity. However, there are ambiguities in the description of tipping cascades within the literature so far. Here we illustrate how different patterns of multiple tipping dynamics emerge from a very simple coupling of two previously studied idealized tipping elements. In particular, we distinguish between a two phase cascade, a domino cascade and a joint cascade. A mitigation of an unfolding two phase cascade may be possible and common early warning indicators are sensitive to upcoming critical transitions to a certain degree. In contrast, a domino cascade may hardly be stopped once initiated and critical slowing down-based indicators fail to indicate tipping of the following element. These different potentials for intervention and anticipation across the distinct patterns of multiple tipping dynamics should be seen as a call to be more precise in future analyses of cascading dynamics arising from tipping element interactions in the Earth system.},
language = {en}
}
@article{TiberiusWeyland2023,
author = {Tiberius, Victor and Weyland, Michael},
title = {Identifying constituent elements of entrepreneurship curricula},
series = {Administrative sciences},
volume = {14},
journal = {Administrative sciences},
number = {1},
publisher = {MDPI},
address = {Basel},
issn = {2076-3387},
doi = {10.3390/admsci14010001},
pages = {18},
year = {2023},
abstract = {Entrepreneurship education research has a strong "output" focus on impact studies but pays much less attention to the "inside" or process perspective of the way entrepreneurship education occurs. In particular, the scattered previous entrepreneurship curriculum research has not managed to provide a current and comprehensive overview of the curricular elements that constitute entrepreneurship education. To overcome this shortcoming, we aim to identify the teaching objectives, teaching contents, teaching methods, and assessment methods discussed in entrepreneurship curriculum research. To this end, we conducted a systematic literature review on the four entrepreneurship curriculum dimensions and collected all mentioned curriculum items. We used a two-stage coding procedure to find the genuinely entrepreneurship-specific items. Among numerous items (also from business management and other subjects), we found 26 objectives, 34 contents, 11 teaching methods, and 7 assessment methods that were entrepreneurship-specific. Most of these items were addressed by only a few scholarly papers.},
language = {en}
}
@article{RomeroBarbosaCoelhoScheiffeleetal.2021,
author = {Romero Barbosa, Lu{\´i}s and Coelho, Victor Hugo R. and Scheiffele, Lena and Baroni, Gabriele and Ramos Filho, Geraldo M. and Montenegro, Suzana M. G. L. and Das Neves Almeida, Cristiano and Oswald, Sascha},
title = {Dynamic groundwater recharge simulations based on cosmic-ray neutron sensing in a tropical wet experimental basin},
series = {Vadose zone journal : VZJ : advancing critical zone science},
volume = {20},
journal = {Vadose zone journal : VZJ : advancing critical zone science},
number = {4},
publisher = {Wiley},
address = {Hoboken},
issn = {1539-1663},
doi = {10.1002/vzj2.20145},
pages = {22},
year = {2021},
abstract = {Although cosmic-ray neutron sensing (CRNS) is probably the most promising noninvasive proximal soil moisture measurement technique at the field scale, its application for hydrological simulations remains underexplored in the literature so far. This study assessed the use of CRNS to inversely calibrate soil hydraulic parameters at the intermediate field scale to simulate the groundwater recharge rates at a daily timescale. The study was conducted for two contrasting hydrological years at the Guaraira experimental basin, Brazil, a 5.84-km(2), a tropical wet and rather flat landscape covered by secondary Atlantic forest. As a consequence of the low altitude and proximity to the equator low neutron count rates could be expected, reducing the precision of CRNS while constituting unexplored and challenging conditions for CRNS applications. Inverse calibration for groundwater recharge rates was used based on CRNS or point-scale soil moisture data. The CRNS-derived retention curve and saturated hydraulic conductivity were consistent with the literature and locally performed slug tests. Simulated groundwater recharge rates ranged from 60 to 470 mm yr(-1), corresponding to 5 and 29\% of rainfall, and correlated well with estimates based on water table fluctuations. In contrast, the estimated results based on inversive point-scale datasets were not in alignment with measured water table fluctuations. The better performance of CRNS-based estimations of field-scale hydrological variables, especially groundwater recharge, demonstrated its clear advantages over traditional invasive point-scale techniques. Finally, the study proved the ability of CRNS as practicable in low altitude, tropical wet areas, thus encouraging its adoption for water resources monitoring and management.},
language = {en}
}
@article{DurandvandenBroekeLeCozannetetal.2022,
author = {Durand, Gael and van den Broeke, Michiel R. and Le Cozannet, Goneri and Edwards, Tamsin L. and Holland, Paul R. and Jourdain, Nicolas C. and Marzeion, Ben and Mottram, Ruth and Nicholls, Robert J. and Pattyn, Frank and Paul, Frank and Slangen, Aimee B. A. and Winkelmann, Ricarda and Burgard, Clara and van Calcar, Caroline J. and Barre, Jean-Baptiste and Bataille, Amelie and Chapuis, Anne},
title = {Sea-Level rise: from global perspectives to local services},
series = {Frontiers in Marine Science},
volume = {8},
journal = {Frontiers in Marine Science},
publisher = {Frontiers Media},
address = {Lausanne},
issn = {2296-7745},
doi = {10.3389/fmars.2021.709595},
pages = {8},
year = {2022},
abstract = {Coastal areas are highly diverse, ecologically rich, regions of key socio-economic activity, and are particularly sensitive to sea-level change. Over most of the 20th century, global mean sea level has risen mainly due to warming and subsequent expansion of the upper ocean layers as well as the melting of glaciers and ice caps. Over the last three decades, increased mass loss of the Greenland and Antarctic ice sheets has also started to contribute significantly to contemporary sea-level rise. The future mass loss of the two ice sheets, which combined represent a sea-level rise potential of similar to 65 m, constitutes the main source of uncertainty in long-term (centennial to millennial) sea-level rise projections. Improved knowledge of the magnitude and rate of future sea-level change is therefore of utmost importance. Moreover, sea level does not change uniformly across the globe and can differ greatly at both regional and local scales. The most appropriate and feasible sea level mitigation and adaptation measures in coastal regions strongly depend on local land use and associated risk aversion. Here, we advocate that addressing the problem of future sea-level rise and its impacts requires (i) bringing together a transdisciplinary scientific community, from climate and cryospheric scientists to coastal impact specialists, and (ii) interacting closely and iteratively with users and local stakeholders to co-design and co-build coastal climate services, including addressing the high-end risks.},
language = {en}
}
@misc{MorenoRomeroProbstTrindadeetal.2020,
author = {Moreno-Romero, Jordi and Probst, Aline V. and Trindade, In{\^e}s and Kalyanikrishna, and Engelhorn, Julia and Farrona, Sara},
title = {Looking At the Past and Heading to the Future},
series = {Frontiers in Plant Science},
volume = {10},
journal = {Frontiers in Plant Science},
number = {1795},
publisher = {Frontiers Media},
address = {Lausanne},
issn = {1664-462X},
doi = {10.3389/fpls.2019.01795},
pages = {1 -- 12},
year = {2020},
abstract = {In June 2019, more than a hundred plant researchers met in Cologne, Germany, for the 6th European Workshop on Plant Chromatin (EWPC). This conference brought together a highly dynamic community of researchers with the common aim to understand how chromatin organization controls gene expression, development, and plant responses to the environment. New evidence showing how epigenetic states are set, perpetuated, and inherited were presented, and novel data related to the three-dimensional organization of chromatin within the nucleus were discussed. At the level of the nucleosome, its composition by different histone variants and their specialized histone deposition complexes were addressed as well as the mechanisms involved in histone post-translational modifications and their role in gene expression. The keynote lecture on plant DNA methylation by Julie Law (SALK Institute) and the tribute session to Lars Hennig, honoring the memory of one of the founders of the EWPC who contributed to promote the plant chromatin and epigenetic field in Europe, added a very special note to this gathering. In this perspective article we summarize some of the most outstanding data and advances on plant chromatin research presented at this workshop.},
language = {en}
}
@article{PangDietrichTewsetal.2020,
author = {Pang, Peter Tsun Ho and Dietrich, Tim and Tews, Ingo and Van Den Broeck, Chris},
title = {Parameter estimation for strong phase transitions in supranuclear matter using gravitational-wave astronomy},
series = {Physical review research},
volume = {2},
journal = {Physical review research},
number = {3},
publisher = {American Physical Society},
address = {College Park},
issn = {2643-1564},
doi = {10.1103/PhysRevResearch.2.033514},
pages = {17},
year = {2020},
abstract = {At supranuclear densities, explored in the core of neutron stars, a strong phase transition from hadronic matter to more exotic forms of matter might be present. To test this hypothesis, binary neutron-star mergers offer a unique possibility to probe matter at densities that we cannot create in any existing terrestrial experiment. In this work, we show that, if present, strong phase transitions can have a measurable imprint on the binary neutron-star coalescence and the emitted gravitational-wave signal. We construct a new parametrization of the supranuclear equation of state that allows us to test for the existence of a strong phase transition and extract its characteristic properties purely from the gravitational-wave signal of the inspiraling neutron stars. We test our approach using a Bayesian inference study simulating 600 signals with three different equations of state and find that for current gravitational-wave detector networks already 12 events might be sufficient to verify the presence of a strong phase transition. Finally, we use our methodology to analyze GW170817 and GW190425 but do not find any indication that a strong phase transition is present at densities probed during the inspiral.},
language = {en}
}
@misc{BullaCoughlinDhawanetal.2022,
author = {Bulla, Mattia and Coughlin, Michael W. and Dhawan, Suhail and Dietrich, Tim},
title = {Multi-messenger constraints on the Hubble constant through combination of gravitational waves, gamma-ray bursts and kilonovae from neutron star mergers},
series = {Universe : open access journal},
volume = {8},
journal = {Universe : open access journal},
number = {5},
publisher = {MDPI},
address = {Basel},
issn = {2218-1997},
doi = {10.3390/universe8050289},
pages = {21},
year = {2022},
abstract = {The simultaneous detection of gravitational waves and light from the binary neutron star merger GW170817 led to independent measurements of distance and redshift, providing a direct estimate of the Hubble constant H-0 that does not rely on a cosmic distance ladder, nor assumes a specific cosmological model. By using gravitational waves as "standard sirens", this approach holds promise to arbitrate the existing tension between the H-0 value inferred from the cosmic microwave background and those obtained from local measurements. However, the known degeneracy in the gravitational-wave analysis between distance and inclination of the source led to a H-0 value from GW170817 that was not precise enough to resolve the existing tension. In this review, we summarize recent works exploiting the viewing-angle dependence of the electromagnetic signal, namely the associated short gamma-ray burst and kilonova, to constrain the system inclination and improve on H-0. We outline the key ingredients of the different methods, summarize the results obtained in the aftermath of GW170817 and discuss the possible systematics introduced by each of these methods.},
language = {en}
}
@article{TiberiusWeyland2024,
author = {Tiberius, Victor and Weyland, Michael},
title = {Improving curricula for higher entrepreneurship education},
series = {Education sciences},
volume = {14},
journal = {Education sciences},
number = {2},
publisher = {MDPI},
address = {Basel},
issn = {2227-7102},
doi = {10.3390/educsci14020130},
pages = {1 -- 17},
year = {2024},
abstract = {Existing curricula for entrepreneurship education do not necessarily represent the best way of teaching. How could entrepreneurship curricula be improved? To answer this question, we aim to identify and rank desirable teaching objectives, teaching contents, teaching methods, and assessment methods for higher entrepreneurship education. To this end, we employ an international real-time Delphi study with an expert panel consisting of entrepreneurship education instructors and researchers. The study reveals 17 favorable objectives, 17 items of content, 25 teaching methods, and 15 assessment methods, which are ranked according to their desirability and the group consensus. We contribute to entrepreneurship curriculum research by adding a normative perspective.},
language = {en}
}