34 results on '"Lambert, Erwin"'
Search Results
2. Sea level rise risks and societal adaptation benefits in low-lying coastal areas
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Magnan, Alexandre K., Oppenheimer, Michael, Garschagen, Matthias, Buchanan, Maya K., Duvat, Virginie K. E., Forbes, Donald L., Ford, James D., Lambert, Erwin, Petzold, Jan, Renaud, Fabrice G., Sebesvari, Zita, van de Wal, Roderik S. W., Hinkel, Jochen, and Pörtner, Hans-Otto
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- 2022
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3. Unveiling spatial variability within the Dotson Melt Channel through high-resolution basal melt rates from the Reference Elevation Model of Antarctica
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Zinck, Ann-Sofie Priergaard, primary, Wouters, Bert, additional, Lambert, Erwin, additional, and Lhermitte, Stef, additional
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- 2023
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4. Antarctic Ice Sheet and emission scenario controls on 21st-century extreme sea-level changes
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Frederikse, Thomas, Buchanan, Maya K., Lambert, Erwin, Kopp, Robert E., Oppenheimer, Michael, Rasmussen, D. J., and Wal, Roderik S. W. van de
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- 2020
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5. Plausible future freshwater forcing simulations with the standard and high-resolution EC-Earth3
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Jüling, André, Le Bars, Dewi, Lambert, Erwin, and Drijfhout, Sybren
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Freshwater fluxes to the ocean from the Greenland and Antarctic ice sheets are increasing and influencing multiple aspects of the climate response. As temperatures continue to rise, the influence of freshwater from the melting ice sheets will play a bigger and bigger climate role. However, the evolution of these fluxes is usually not well represented in current climate model simulations as ice sheets are not modelled interactively. We develop plausible, future freshwater forcing scenarios for both ice sheets until 2100 and use both standard-resolution (non-eddying) and high-resolution (eddy-permitting) versions of EC-Earth3 to simulate the response to a high emission scenario. We investigate the effect of this additional freshwater on sea ice, ocean heat uptake and circulation, surface temperatures, and sea level. By comparing the simulations to the HighResMIP EC-Earth3 simulations without these additional freshwater fluxes from ice sheet mass loss as well as the EC-Earth contribution to the Southern Ocean Freshwater release model experiments Initiative (SOFIAMIP), we can discern effects of ocean model resolution and freshwater flux amount., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)
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- 2023
6. Modelling Antarctic ice shelf basal melt patterns using the one-layer Antarctic model for dynamical downscaling of ice-ocean exchanges (LADDIE v1.0)
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Sub Dynamics Meteorology, Afd Marine and Atmospheric Research, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Lambert, Erwin, Jüling, André, Van De Wal, Roderik S.W., Holland, Paul R., Sub Dynamics Meteorology, Afd Marine and Atmospheric Research, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Lambert, Erwin, Jüling, André, Van De Wal, Roderik S.W., and Holland, Paul R.
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- 2023
7. Decision-support for land reclamation location and design choices in the Maldives
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Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Netherlands Organization for Scientific Research, Agence Nationale de la Recherche (France), European Commission, Govern de les Illes Balears, Gussmann, Geronimo [0000-0002-3451-0370], Pol, Thomas van der, Gussmann, Geronimo, Hinkel, Jochen, Amores, Ángel, Marcos, Marta, Rohmer, Jérémy, Lambert, Erwin, Bisaro, Alexander, Federal Ministry of Education and Research (Germany), Ministerio de Economía y Competitividad (España), Netherlands Organization for Scientific Research, Agence Nationale de la Recherche (France), European Commission, Govern de les Illes Balears, Gussmann, Geronimo [0000-0002-3451-0370], Pol, Thomas van der, Gussmann, Geronimo, Hinkel, Jochen, Amores, Ángel, Marcos, Marta, Rohmer, Jérémy, Lambert, Erwin, and Bisaro, Alexander
- Abstract
Land reclamation in the Maldives is widespread. Current land reclamation practices, however, lack a systematic approach to anticipate sea-level rise and do not account for local flood risk differences to inform location and design choices. To address these limitations, this paper applies two decision-support tools: a hazard threshold analysis, and a cost-benefit analysis. Both tools produce site-specific estimates of land elevations or flood defence heights but do so for different goals. The hazard threshold analysis identifies hazard-based solutions that meet an acceptable flood probability for an intended lifespan without follow-up actions by reliability optimisation. The cost-benefit analysis identifies risk-based solutions using dynamic programming. We apply both tools to two land reclamation sites, a newly reclaimed airport island and a land extension of an inhabited island, in the Maldives. We find that total hazard-based heights for long-term planning horizons are highly uncertain, with local height differences of up to 1.9 m across sea-level rise scenarios by 2100. Risk-based Island elevations, in contrast, differ much less across scenarios, offering a practical advantage for decision-making. However, land reclamation choices on location, land elevation and investment in flood protection are not only driven by hazard-related aspects, such as reef characteristics, swell exposure, and sea-level rise, but also by estimates of exposed assets, reclamation, and flood protection costs. Taken together, the two decision-support tools are helpful for improving adaptation decisions and are also applicable in other small island regions.
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- 2023
8. Unveiling spatial variability within the Dotson Melt Channel through high-resolution basal melt rates from the Reference Elevation Model of Antarctica
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Zinck, A.P. (author), Wouters, B. (author), Lambert, Erwin (author), Lhermitte, S.L.M. (author), Zinck, A.P. (author), Wouters, B. (author), Lambert, Erwin (author), and Lhermitte, S.L.M. (author)
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The intrusion of Circumpolar Deep Water in the Amundsen and Bellingshausen Sea embayments of Antarctica causes ice shelves in the region to melt from below, potentially putting their stability at risk. Earlier studies have shown how digital elevation models can be used to obtain ice shelf basal melt rates at a high spatial resolution. However, there has been limited availability of high-resolution elevation data, a gap the Reference Elevation Model of Antarctica (REMA) has filled. In this study we use a novel combination of REMA and CryoSat-2 elevation data to obtain high-resolution basal melt rates of the Dotson Ice Shelf in a Lagrangian framework, at a 50 m spatial posting on a 3-yearly temporal resolution. We present a novel method: Basal melt rates Using REMA and Google Earth Engine (BURGEE). The high resolution of BURGEE is supported through a sensitivity study of the Lagrangian displacement. The high-resolution basal melt rates show a good agreement with an earlier basal melt product based on CryoSat-2. Both products show a wide melt channel extending from the grounding line to the ice front, but our high-resolution product indicates that the pathway and spatial variability of this channel is influenced by a pinning point on the ice shelf. This result emphasizes the importance of high-resolution basal melt rates to expand our understanding of channel formation and melt patterns. BURGEE can be expanded to a pan-Antarctic study of high-resolution basal melt rates. This will provide a better picture of the (in)stability of Antarctic ice shelves., Physical and Space Geodesy, Mathematical Geodesy and Positioning
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- 2023
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9. Modelling Antarctic ice shelf basal melt patterns using the one-layer Antarctic model for dynamical downscaling of ice–ocean exchanges (LADDIE v1.0)
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Lambert, Erwin, Jüling, André, van de Wal, Roderik S. W., Holland, Paul R., Lambert, Erwin, Jüling, André, van de Wal, Roderik S. W., and Holland, Paul R.
- Abstract
A major source of uncertainty in future sea level projections is the ocean-driven basal melt of Antarctic ice shelves. While ice sheet models require a kilometre-scale resolution to realistically resolve ice shelf stability and grounding line migration, global or regional 3D ocean models are computationally too expensive to produce basal melt forcing fields at this resolution on long timescales. To bridge this resolution gap, we introduce the 2D numerical model LADDIE (one-layer Antarctic model for dynamical downscaling of ice–ocean exchanges), which allows for the computationally efficient modelling of detailed basal melt fields. The model is open source and can be applied easily to different geometries or different ocean forcings. The aim of this study is threefold: to introduce the model to the community, to demonstrate its application and performance in two use cases, and to describe and interpret new basal melt patterns simulated by this model. The two use cases are the small Crosson–Dotson Ice Shelf in the warm Amundsen Sea region and the large Filchner–Ronne Ice Shelf in the cold Weddell Sea. At ice-shelf-wide scales, LADDIE reproduces observed patterns of basal melting and freezing in warm and cold environments without the need to re-tune parameters for individual ice shelves. At scales of 0.5–5 km, which are typically unresolved by 3D ocean models and poorly constrained by observations, LADDIE produces plausible basal melt patterns. Most significantly, the simulated basal melt patterns are physically consistent with the applied ice shelf topography. These patterns are governed by the topographic steering and Coriolis deflection of meltwater flows, two processes that are poorly represented in basal melt parameterisations. The kilometre-scale melt patterns simulated by LADDIE include enhanced melt rates in grounding zones and basal channels and enhanced melt or freezing in shear margins. As these regions are critical for ice shelf stability, we conclude that
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- 2023
10. Antarctic contribution to future sea level from ice shelf basal melt as constrained by ice discharge observations
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van der Linden, Eveline C., primary, Le Bars, Dewi, additional, Lambert, Erwin, additional, and Drijfhout, Sybren, additional
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- 2023
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11. Sea level rise risks and societal adaptation benefits in low-lying coastal areas
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Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Magnan, Alexandre K., Oppenheimer, Michael, Garschagen, Matthias, Buchanan, Maya K., Duvat, Virginie K.E., Forbes, Donald L., Ford, James D., Lambert, Erwin, Petzold, Jan, Renaud, Fabrice G., Sebesvari, Zita, van de Wal, Roderik S.W., Hinkel, Jochen, Pörtner, Hans Otto, Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Magnan, Alexandre K., Oppenheimer, Michael, Garschagen, Matthias, Buchanan, Maya K., Duvat, Virginie K.E., Forbes, Donald L., Ford, James D., Lambert, Erwin, Petzold, Jan, Renaud, Fabrice G., Sebesvari, Zita, van de Wal, Roderik S.W., Hinkel, Jochen, and Pörtner, Hans Otto
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- 2022
12. Contribution of Land Water Storage Change to Regional Sea-Level Rise Over the Twenty-First Century
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Karabil, Sitar, Sutanudjaja, Edwin H., Lambert, Erwin, Bierkens, Marc F.P., Van de Wal, Roderik S.W., Geomorfologie, Hydrologie, Sub Dynamics Meteorology, Landscape functioning, Geocomputation and Hydrology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Geomorfologie, Hydrologie, Sub Dynamics Meteorology, Landscape functioning, Geocomputation and Hydrology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, and Marine and Atmospheric Research
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land water ,010504 meteorology & atmospheric sciences ,Range (biology) ,Science ,0208 environmental biotechnology ,Water storage ,Twenty-First Century ,Climate change ,Earth and Planetary Sciences(all) ,02 engineering and technology ,sea level ,01 natural sciences ,020801 environmental engineering ,Geography ,climate scenarios ,Sea level rise ,human activities ,climate models ,global hydrology ,General Earth and Planetary Sciences ,Climate model ,Physical geography ,West coast ,0105 earth and related environmental sciences - Abstract
Change in Land Water Storage (LWS) is one of the main components driving sea-level rise over the twenty-first century. LWS alteration results from both human activities and climate change. Up to now, all components to sea-level change are usually quantified upon a certain climate change scenario except land water changes. Here, we propose to improve this by analyzing the contribution of LWS to regional sea-level change by considering five Coupled Model Intercomparison Project Phase 5 (CMIP5) climate models forced by three different Representative Concentration Pathway (RCP) greenhouse gas emission scenarios. For this analysis, we used LWS output of the global hydrological and water resources model, PCR-GLOBWB 2, in order to project regional sea-level patterns. Projections of ensemble means indicate a range of LWS-driven sea-level rise with larger differences in projections among climate models than between scenarios. Our results suggest that LWS change will contribute around 10% to the projected global mean sea-level rise by the end of twenty-first century. Contribution of LWS to regional sea-level rise is projected to be considerably larger than the global mean over several regions, up to 60% higher than global average of LWS-driven sea-level rise, including the Pacific islands, the south coast of Africa and the west coast of Australia.
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- 2021
13. Correlations Between Sea-Level Components Are Driven by Regional Climate Change
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Lambert, Erwin, Le Bars, Dewi, Goelzer, Heiko, van de Wal, Roderik S.W., Sub Dynamics Meteorology, Sub Physical Oceanography, Proceskunde, and Sub Algemeen Marine & Atmospheric Res
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projections ,correlations ,model ensemble ,Environmental Science(all) ,regional climate ,Earth and Planetary Sciences (miscellaneous) ,sea level ,uncertainty - Abstract
The accurate quantification of uncertainties in regional sea-level projections is essential for guiding policy makers. As climate models do not currently simulate total sea level, these uncertainties must be quantified through summation of uncertainties in individual sea-level components. This summation depends on the correlation between the components, which has previously been prescribed or derived from each individual component's dependence on global mean surface temperature. In this study, we quantify, for the first time, regional correlations between sea-level components based on regional climate change projections. We compute regional sea-level projections consistent with climate projections from an ensemble of 14 Earth System Models. From the multi-model spread, we estimate the uncertainty in the regional climate's response to greenhouse forcing. To quantify the total uncertainty, we add the uncertainty in the response of sea-level components to this regional climate change. This approach reveals how regional climate processes impose correlations between sea-level components, affecting the total uncertainty. One example is an anti-correlation between North Atlantic sterodynamic change and Antarctic dynamic mass loss, suggesting a teleconnection established by the large-scale ocean circulation. We find that prescribed correlations, applied in the fifth assessment report of the Intergovernmental Panel on Climate Change, lead to a global overestimation in the uncertainty in regional sea-level projections on the order of 20%. Regionally, this overestimation exceeds 100%. We conclude that accurate uncertainty estimates of regional sea-level change must be based on projections of regional climate change and cannot be derived from global indicators such as global mean surface temperature.
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- 2021
14. Contribution of Land Water Storage Change to Regional Sea-Level Rise Over the Twenty-First Century
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Geomorfologie, Hydrologie, Sub Dynamics Meteorology, Landscape functioning, Geocomputation and Hydrology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Karabil, Sitar, Sutanudjaja, Edwin H., Lambert, Erwin, Bierkens, Marc F.P., Van de Wal, Roderik S.W., Geomorfologie, Hydrologie, Sub Dynamics Meteorology, Landscape functioning, Geocomputation and Hydrology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Karabil, Sitar, Sutanudjaja, Edwin H., Lambert, Erwin, Bierkens, Marc F.P., and Van de Wal, Roderik S.W.
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- 2021
15. Correlations Between Sea-Level Components Are Driven by Regional Climate Change
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Sub Dynamics Meteorology, Sub Physical Oceanography, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Lambert, Erwin, Le Bars, Dewi, Goelzer, Heiko, van de Wal, Roderik S.W., Sub Dynamics Meteorology, Sub Physical Oceanography, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Lambert, Erwin, Le Bars, Dewi, Goelzer, Heiko, and van de Wal, Roderik S.W.
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- 2021
16. Calibration of basal melt on past ice discharge lowers projections of Antarctica’s sea level contribution
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Sub Physical Oceanography, Sub Dynamics Meteorology, Marine and Atmospheric Research, van der Linden, Eveline C., Le Bars, Dewi, Lambert, Erwin, Drijfhout, Sybren, Sub Physical Oceanography, Sub Dynamics Meteorology, Marine and Atmospheric Research, van der Linden, Eveline C., Le Bars, Dewi, Lambert, Erwin, and Drijfhout, Sybren
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- 2021
17. Unravelling the Importance of Uncertainties in Global-Scale Coastal Flood Risk Assessments under Sea Level Rise
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Rohmer, Jeremy, primary, Lincke, Daniel, additional, Hinkel, Jochen, additional, Le Cozannet, Gonéri, additional, Lambert, Erwin, additional, and Vafeidis, Athanasios T., additional
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- 2021
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18. Correlations Between Sea‐Level Components Are Driven by Regional Climate Change
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Lambert, Erwin, primary, Le Bars, Dewi, additional, Goelzer, Heiko, additional, and van de Wal, Roderik S.W., additional
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- 2021
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19. Adaptation time to magnified flood hazards underestimated when derived from tide gauge records
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Lambert, Erwin, Rohmer, Jeremy, Le Cozannet, Gonéri, Van De Wal, Roderik S.W., Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, and Marine and Atmospheric Research
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joint probability ,Sea-level rise ,010504 meteorology & atmospheric sciences ,Adaptation (eye) ,01 natural sciences ,03 medical and health sciences ,extreme water level ,Environmental Science(all) ,waves ,Renewable Energy ,030304 developmental biology ,0105 earth and related environmental sciences ,General Environmental Science ,0303 health sciences ,Flood myth ,Sustainability and the Environment ,Renewable Energy, Sustainability and the Environment ,Environmental and Occupational Health ,Public Health, Environmental and Occupational Health ,coastal adaptation ,Sea level rise ,13. Climate action ,Climatology ,Environmental science ,Tide gauge ,Public Health - Abstract
Sea-level rise magnifies flood hazards, raising the question when adaptation measures need to be taken. Here, we quantify when the recurrence of extreme water level events will double due to projected sea-level rise. Reproducing the most common method based on extreme water levels observed with tide gauges, at least one third of the coastal locations are to expect a doubling of extremes within a decade. However, tide gauges are commonly placed in wave-sheltered harbours where the contribution of waves to water levels is much smaller than at nearby wave-exposed coastlines such as beaches and dikes. In this study, we quantify doubling times at a variety of idealised shorelines based on modelled tides, storm surges and waves. We apply an extreme value analysis that accounts for the joint probability of extreme storm surges and extreme waves. Our results indicate that doubling times at wave-exposed shorelines are longer than those in wave-sheltered harbours, allowing for more time to adapt to magnified flood hazards. The median doubling times of average water levels including parameterised wave set-up are 1.2 to 5 times longer than those of still water levels as observed with tide gauges. For instantaneous water levels including wave run-up, doubling times are an additional 30% to 100% longer. We conclude that tide gauge-based analyses underestimate adaptation times by underestimating the contribution of waves to extreme water levels, and provide a quantitative framework to guide adaptation policy at wave-exposed shorelines.
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- 2020
20. The contrasting dynamics of the buoyancy-forced Lofoten and Greenland Basins
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Ypma, Stefanie, Spall, Michael A., Lambert, Erwin, Georgiou, Sotiria, Pietrazak, Julie D., Katsman, Caroline A., Ypma, Stefanie, Spall, Michael A., Lambert, Erwin, Georgiou, Sotiria, Pietrazak, Julie D., and Katsman, Caroline A.
- Abstract
Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 50(5),(2020): 1227-1244, doi:10.1175/JPO-D-19-0280.1., The Nordic seas are commonly described as a single basin to investigate their dynamics and sensitivity to environmental changes when using a theoretical framework. Here, we introduce a conceptual model for a two-basin marginal sea that better represents the Nordic seas geometry. In our conceptual model, the marginal sea is characterized by both a cyclonic boundary current and a front current as a result of different hydrographic properties east and west of the midocean ridge. The theory is compared to idealized model simulations and shows good agreement over a wide range of parameter settings, indicating that the physics in the two-basin marginal sea is well captured by the conceptual model. The balances between the atmospheric buoyancy forcing and the lateral eddy heat fluxes from the boundary current and the front current differ between the Lofoten and the Greenland Basins, since the Lofoten Basin is more strongly eddy dominated. Results show that this asymmetric sensitivity leads to opposing responses depending on the strength of the atmospheric buoyancy forcing. Additionally, the front current plays an essential role for the heat and volume budget of the two basins, by providing an additional pathway for heat toward the interior of both basins via lateral eddy heat fluxes. The variability of the temperature difference between east and west influences the strength of the different flow branches through the marginal sea and provides a dynamical explanation for the observed correlation between the front current and the slope current of the Norwegian Atlantic Current in the Nordic seas., We thank Ilker Fer and two anonymous reviewers whose comments improved this paper. S. L. Ypma and S. Georgiou were supported by NWO (Netherlands Organisation for Scientific Research) VIDI Grant 864.13.011 awarded to C. A. Katsman. M. A. Spall was supported by National Science Foundation Grants OCE-1558742 and OPP-1822334. E. Lambert is funded by the ERA4CS project INSeaPTION. The model data analyzed in this study are available on request from the corresponding author. This study has been conducted using E.U. Copernicus Marine Service Information. The altimeter products were produced by Ssalto/Duacs and distributed by Aviso+, with support from CNES (https://www.aviso.altimetry.fr)., 2020-10-27
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- 2020
21. Adaptation time to magnified flood hazards underestimated when derived from tide gauge records
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Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Lambert, Erwin, Rohmer, Jeremy, Le Cozannet, Gonéri, Van De Wal, Roderik S.W., Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, Marine and Atmospheric Research, Lambert, Erwin, Rohmer, Jeremy, Le Cozannet, Gonéri, and Van De Wal, Roderik S.W.
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- 2020
22. A Stella® version of the Arctic Mediterranean Double Estuarine Circulation model: SAMDEC v1.0
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Lambert, Erwin and Thibodeau, Benoit
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bepress|Physical Sciences and Mathematics ,EarthArXiv|Physical Sciences and Mathematics|Oceanography and Atmospheric Sciences and Meteorology ,EarthArXiv|Physical Sciences and Mathematics|Environmental Sciences ,bepress|Physical Sciences and Mathematics|Oceanography and Atmospheric Sciences and Meteorology ,bepress|Physical Sciences and Mathematics|Earth Sciences ,bepress|Physical Sciences and Mathematics|Environmental Sciences ,EarthArXiv|Physical Sciences and Mathematics|Earth Sciences ,EarthArXiv|Physical Sciences and Mathematics - Abstract
The Arctic Mediterranean can be described as a double estuarine circulation regime. This observed circulation feature, which connects the North Atlantic to the Arctic Ocean, is composed of two interconnected branches of circulation: an overturning circulation, where dense water formed in the Nordic Seas returns toward the Atlantic and an estuarine circulation, where the East Greenland Current exits the Arctic Mediterranean. A conceptual box model has previously built upon Henry Stommel’s original version, concluding that a double estuarine circulation is less sensitive to perturbations in northern freshwater input than an overturning circulation in isolation. This extended model exhibits a similar freshwater sensitivity to several coupled atmosphere-ocean general circulation models (AOGCMs), which require about 1 Sv of freshwater input to induce a transition to a qualitatively weakened overturning in the Atlantic Ocean. Besides the amount of freshwater that would be required to abruptly weaken the Atlantic overturning circulation, it is essential to determine over what time scale such a transition could occur. To address this temporal aspect of potential abrupt transitions in a double estuarine circulation, we built a numerical version of the box-model in Stella®. The Stella® version of the Arctic Mediterranean Double Estuarine Circulation model (SAMDEC) is thus a new and widely-available numerical box-model representing the Arctic Mediterranean Double Estuarine Circulation and is intended to provide a numerical tool to easily solve this double estuarine theoretical framework. In addition to its simplicity of use, one of the most important added values of SAMDEC is the ability to easily determine and visualise transition times between two circulation regimes at very low computing cost, making it a valuable tool for research and education. This allows for a quantitative assessment of the response of the Arctic Mediterranean circulation to variable freshwater fluxes and temperature changes over short and long time scales. To highlight the features of SAMDEC, we showcase here two freshwater flux scenarios; 1) increased freshwater input in the Nordic Seas, which is most comparable to common ‘hosing’ experiments; and 2) increased freshwater input in the Nordic Seas and the Arctic. Similar to previous experiments performed with AOGCMs, the weakening caused by realistic freshwater addition is relatively slow during the first 100 years of simulation and increases thereafter. Finally, under a realistic freshwater increase, SAMDEC indicates that 88 to 176 years are needed to achieve a 15% weakening of the overturning. Overall, SAMDEC can provide insights into the dynamic of transition between circulation regimes under changes in freshwater input for both near-future and geological timescale investigations. A light version of the model can be accessed online with any internet browser and the full model can be downloaded, modified and used on a personal computer.
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- 2019
23. Tracing the Imprint of River Runoff Variability on Arctic Water Mass Transformation
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Lambert, Erwin, Nummelin, Pemberton, Ilicak, Marine and Atmospheric Research, and Sub Dynamics Meteorology
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climate response function ,Arctic Ocean ,water mass transformation ,river runoff - Abstract
The Arctic Ocean receives a net freshwater input from land and from the atmosphere. This flux of freshwater, along with net surface heat loss, acts to transform the water mass properties of inflowing Atlantic and Pacific waters. In this study, model simulations are used to quantify the Arctic water mass transformation in salinity and temperature space, and its explained variance due to variability in the largest freshwater source to the Arctic: river runoff. This explained variance is quantified using a novel tool, the seasonal climate response function, which describes the magnitude and time scale of adjustment to a runoff perturbation at monthly resolution. Using this method, the transient response of Arctic water mass transformation is reconstructed over time scales ranging from several months to a decade. Model simulations with variable runoff indicate a significant explained model variance of several terms contributing to salinity transformation, including diffusion, the formation and melt of sea ice, and a possibly model‐dependent surface salinity‐restoring term. Most notably, an increase in river runoff strengthens the diffusion of salt and heat, which ultimately leads to an increase in the advective salt and heat import into the Arctic. These results provide evidence for the potential predictability of the Arctic system based on variability in river runoff.
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- 2019
24. Toward a unified approach to quantify uncertainties in sea-level projections
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Nicholls, Robert, Slangen, Aimée, Ritz, Catherine, Salas-y-Mélia, David, Rohmer, Jeremy, Meyssignac, Benoit, Melet, Angélique, Carson, Mark, manceau, van de Wal, Roderik, Stammer, Detlef, Durand, Gael, Lambert, Erwin, Le Cozannet, Goneri, and Hinkel, Jochen
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bepress|Physical Sciences and Mathematics ,EarthArXiv|Physical Sciences and Mathematics|Earth Sciences|Other Earth Sciences ,bepress|Physical Sciences and Mathematics|Earth Sciences|Other Earth Sciences ,bepress|Physical Sciences and Mathematics|Earth Sciences ,EarthArXiv|Physical Sciences and Mathematics|Earth Sciences ,EarthArXiv|Physical Sciences and Mathematics - Abstract
Coastal impacts of climate change and the related mitigation and adaptation needs requires assessments of future sea-level changes. Following a common practice in coastal engineering, probabilistic sea-level projections have been proposed for at least 20 years. This requires a probability model to represent the uncertainties of future sea-level rise, which is not achievable because potential ice sheets mass losses remain poorly understood given the knowledge available today. Here, we apply the principles of extra-probabilistic theories of uncertainties to generate global and regional sea-level projections based on uncertain components. This approach assigns an imprecision to a probabilistic measure, in order to quantify lack of knowledge pertaining to probabilistic projections. This can serve to understand, analyze and communicate uncertainties due to the coexistence of different processes contributing to future sea-level rise, including ice-sheets. We show that the knowledge gained since the 5th Assessment report of the IPCC allows better quantification of how global and regional sea-level rise uncertainties can be reduced with lower greenhouse gas emissions. Furthermore, Europe and Northern America are among those profiting most from a policy limiting climate change to RCP 2.6 versus RCP 4.5 in terms of reducing uncertainties of sea-level rise.
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- 2018
25. Meeting User Needs for Sea Level Rise Information: A Decision Analysis Perspective
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Sub Dynamics Meteorology, Marine and Atmospheric Research, Hinkel, Jochen, Church, John A., Gregory, Jonathan M., Lambert, Erwin, Le Cozannet, Gonéri, Lowe, Jason, McInnes, Kathleen L., Nicholls, Robert J., van der Pol, Thomas D., van de Wal, Roderik, Sub Dynamics Meteorology, Marine and Atmospheric Research, Hinkel, Jochen, Church, John A., Gregory, Jonathan M., Lambert, Erwin, Le Cozannet, Gonéri, Lowe, Jason, McInnes, Kathleen L., Nicholls, Robert J., van der Pol, Thomas D., and van de Wal, Roderik
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- 2019
26. Tracing the Imprint of River Runoff Variability on Arctic Water Mass Transformation
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Marine and Atmospheric Research, Sub Dynamics Meteorology, Lambert, Erwin, Nummelin, Pemberton, Ilicak, Marine and Atmospheric Research, Sub Dynamics Meteorology, Lambert, Erwin, Nummelin, Pemberton, and Ilicak
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- 2019
27. Meeting User Needs for Sea Level Rise Information: A Decision Analysis Perspective
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Hinkel, Jochen, Church, John A., Gregory, Jonathan M., Lambert, Erwin, Le Cozannet, Goneri, Lowe, Jason, Mcinnes, Kathleen L., Nicholls, Robert J., Van Der Pol, Thomas D., Van De Wal, Roderik, Hinkel, Jochen, Church, John A., Gregory, Jonathan M., Lambert, Erwin, Le Cozannet, Goneri, Lowe, Jason, Mcinnes, Kathleen L., Nicholls, Robert J., Van Der Pol, Thomas D., and Van De Wal, Roderik
- Abstract
Despite widespread efforts to implement climate services, there is almost no literature that systematically analyzes users' needs. This paper addresses this gap by applying a decision analysis perspective to identify what kind of mean sea level rise (SLR) information is needed for local coastal adaptation decisions. We first characterize these decisions, then identify suitable decision analysis approaches and the sea level information required, and finally discuss if and how these information needs can be met given the state of the art of sea level science. We find that four types of information are needed: (i) probabilistic predictions for short-term decisions when users are uncertainty tolerant; (ii) high-end and low-end SLR scenarios chosen for different levels of uncertainty tolerance; (iii) upper bounds of SLR for users with a low uncertainty tolerance; and (iv) learning scenarios derived from estimating what knowledge will plausibly emerge about SLR over time. Probabilistic predictions can only be attained for the near term (i.e., 2030-2050) before SLR significantly diverges between low and high emission scenarios, for locations for which modes of climate variability are well understood and the vertical land movement contribution to local sea levels is small. Meaningful SLR upper bounds cannot be defined unambiguously from a physical perspective. Low- to high-end scenarios for different levels of uncertainty tolerance and learning scenarios can be produced, but this involves both expert and user judgments. The decision analysis procedure elaborated here can be applied to other types of climate information that are required for mitigation and adaptation purposes.
- Published
- 2019
- Full Text
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28. Meeting User Needs for Sea Level Rise Information: A Decision Analysis Perspective
- Author
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Hinkel, Jochen, primary, Church, John A., additional, Gregory, Jonathan M., additional, Lambert, Erwin, additional, Le Cozannet, Gonéri, additional, Lowe, Jason, additional, McInnes, Kathleen L., additional, Nicholls, Robert J., additional, van der Pol, Thomas D., additional, and van de Wal, Roderik, additional
- Published
- 2019
- Full Text
- View/download PDF
29. On freshwater and the density-driven circulation in the northern seas
- Author
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Lambert, Erwin
- Abstract
The Arctic Ocean and the Nordic Seas are freshening, in part due to anthropogenic climate change. Within the northern seas, seawater density is in part dominated by temperature, and in part by salinity. This reflects on the density-driven circulation in the northern seas which consists of two coupled branches of circulation: an overturning branch dominated by temperature, and an estuarine branch dominated by salinity. In order to assess how observed and projected increase in freshwater input into the northern seas can change this circulation, a better understanding of its governing dynamics is required. Using a hierarchy of theory and models, this dissertation studies how freshwater impacts the strength, stability, and variability of the density-driven circulation in the northern seas. Whereas freshwater is commonly perceived as suppressing a temperaturedominated circulation, models of various complexity indicate that increased freshwater input into low-salinity surface waters can spin up the salinity-dominated circulation. This results in a freshwater-induced increase in the poleward transport of Atlantic Water and heat. The coupling of the two circulation branches stabilises the density-driven circulation with respect to perturbations in freshwater, and abrupt transitions in the temperature-dominated circulation can only be induced by sufficient, localized freshwater input into dense surface waters. Finally, the transient response of the temperatureand salinity-modification of AtlanticWater in the Arctic Ocean to perturbations in Arctic river runoff is quantified; this indicates a potential predictability of regional processes at monthly resolution. This dissertation describes the unique behaviour of coupled temperature- and salinitydominated branches of density-driven ocean circulation. It reveals a glimpse of the largely unexplored potential for interaction between subtropical and polar ocean circulation. For the northern seas, this interaction translates into freshwater-sensitivity of the density-driven circulation that appears relatively weak and less dominant than what is commonly understood. As this circulation is integrated in the large-scale ocean circulation beyond the northern seas, these findings would have implications for the sensitivity of the global ocean circulation to future perturbations in high-latitude freshwater input.
- Published
- 2017
30. On the dynamics and water mass transformation of a boundary current connecting alpha and beta oceans
- Author
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Lambert, Erwin, Eldevik, Tor, Spall, Michael A., Lambert, Erwin, Eldevik, Tor, and Spall, Michael A.
- Abstract
Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 2457-2475, doi:10.1175/JPO-D-17-0186.1., A subpolar marginal sea, like the Nordic seas, is a transition zone between the temperature-stratified subtropics (the alpha ocean) and the salinity-stratified polar regions (the beta ocean). An inflow of Atlantic Water circulates these seas as a boundary current that is cooled and freshened downstream, eventually to outflow as Deep and Polar Water. Stratification in the boundary region is dominated by a thermocline over the continental slope and a halocline over the continental shelves, separating Atlantic Water from Deep and Polar Water, respectively. A conceptual model is introduced for the circulation and water mass transformation in a subpolar marginal sea to explore the potential interaction between the alpha and beta oceans. Freshwater input into the shelf regions has a slight strengthening effect on the Atlantic inflow, but more prominently impacts the water mass composition of the outflow. This impact of freshwater, characterized by enhancing Polar Water outflow and suppressing Deep Water outflow, is strongly determined by the source location of freshwater. Concretely, perturbations in upstream freshwater sources, like the Baltic freshwater outflow into the Nordic seas, have an order of magnitude larger potential to impact water mass transports than perturbations in downstream sources like the Arctic freshwater outflow. These boundary current dynamics are directly related to the qualitative stratification in transition zones and illustrate the interaction between the alpha and beta oceans., This research was supported by the Research Council of Norway project NORTH. Support for the publication was provided by the University of Bergen. Ocean Outlook has supported a research visit for EL to Woods Hole Oceanographic Institute where much of the current work has been carried out. Support forMAS was provided by the National Science Foundation Grant OCE-1558742.
- Published
- 2018
31. On the Dynamics and Water Mass Transformation of a Boundary Current Connecting Alpha and Beta Oceans
- Author
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Lambert, Erwin, primary, Eldevik, Tor, additional, and Spall, Michael A., additional
- Published
- 2018
- Full Text
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32. How northern freshwater input can stabilise thermohaline circulation
- Author
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Lambert, Erwin, primary, Eldevik, Tor, additional, and Haugan, Peter M., additional
- Published
- 2016
- Full Text
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33. The connection of the Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current
- Author
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Lambert, Erwin, primary, Le Bars, Dewi, additional, and de Ruijter, Wilhelmus P. M., additional
- Published
- 2016
- Full Text
- View/download PDF
34. How wave runup can suppress the amplification of extreme coastal water levels due to sea-level rise.
- Author
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Lambert, Erwin, Rohmer, Jeremy, Cozannet, Goneri Le, and van de Wal, Roderik
- Subjects
- *
TERRITORIAL waters , *WATER levels , *ROGUE waves , *STORM surges - Abstract
Sea-level rise will amplify the occurrence frequency of extreme coastal water levels along nearly all inhabited coastlines. A good understanding of how this amplification will develop over the 21st century can help communicating the benefits of mitigation and aid decision-makers in the planning of adaptation strategies. The frequency amplification of extremes is strongly modulated by the variance in extreme coastal water levels, driven by astronomical tides, storm surges and waves. However, wave effects, and particularly wave runup, are rarely incorporated in the analysis of extremes. In this study, we quantify the influence of wave runup on extremes at a number of coastal sites which span a wide range of coastal climates and tidal regimes. Using a joint probability method following Heffernan and Tawn (2004), we simulate a large number of extreme coastal water levels, considering the potential covariance in extreme storm surges and waves. Wave runup is derived from reanalysis wave data using a range of five parametrizations which vary in their complexity and their specific applicability to sandy or gravel beaches. By combining the simulated extremes with projected mean sea-level rise, we compute the frequency amplification of extremes and the influence of wave runup thereon. We conclude that studies which neglect wave runup underestimate the variance in extreme coastal water levels, and may therefore overestimate the frequency amplification of these extremes due to mean sea-level rise. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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