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351 results on '"Mikolajewicz, Uwe"'

51. The ICON Earth System Model Version 1.0

Author

Jungclaus, Johann H, primary, Lorenz, Stephan J., additional, Schmidt, Hauke, additional, Gutjahr, Oliver, additional, Haak, Helmuth, additional, Mehlmann, Carolin, additional, Mikolajewicz, Uwe, additional, Notz, Dirk, additional, Putrashan, Dian, additional, von Storch, Jin-Song, additional, Leonidas, Linardakis, additional, Brokvin, Victor, additional, Chegini, Fatemeh, additional, Gayler, Veronika, additional, Giorgetta, Marco A., additional, Hagemann, Stefan, additional, Ilyina, Tatiana, additional, Korn, Peter, additional, Kröger, Jürgen, additional, Müller, Wolfgang A., additional, Pohlmann, Holger, additional, Raddatz, Thomas Jürgen, additional, Ramme, Lennart, additional, Christian, Reick H., additional, Schneck, Rainer, additional, Schnur, Reiner, additional, Stevens, Bjorn, additional, Ziemen, Florian Andreas, additional, Claussen, Martin, additional, Marotzke, Jochem, additional, Wachsmann, Fabian, additional, Schupfner, Martin, additional, Riddick, Thomas, additional, Wieners, Karl-Hermann, additional, Brueggemann, Nils, additional, Redler, Rene, additional, de Vrese, Philipp, additional, Nabel, Julia Esther Marlene Sophia, additional, Sam, Teffy, additional, and Hanke, Moritz, additional

Published
2021
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53. The PMIP4 Last Glacial Maximum experiments: preliminary results and comparison with the PMIP3 simulations

Author

Kageyama, Masa, primary, Harrison, Sandy P., additional, Kapsch, Marie-L., additional, Lofverstrom, Marcus, additional, Lora, Juan M., additional, Mikolajewicz, Uwe, additional, Sherriff-Tadano, Sam, additional, Vadsaria, Tristan, additional, Abe-Ouchi, Ayako, additional, Bouttes, Nathaelle, additional, Chandan, Deepak, additional, Gregoire, Lauren J., additional, Ivanovic, Ruza F., additional, Izumi, Kenji, additional, LeGrande, Allegra N., additional, Lhardy, Fanny, additional, Lohmann, Gerrit, additional, Morozova, Polina A., additional, Ohgaito, Rumi, additional, Paul, André, additional, Peltier, W. Richard, additional, Poulsen, Christopher J., additional, Quiquet, Aurélien, additional, Roche, Didier M., additional, Shi, Xiaoxu, additional, Tierney, Jessica E., additional, Valdes, Paul J., additional, Volodin, Evgeny, additional, and Zhu, Jiang, additional

Published
2021
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54. GrSMBMIP: Intercomparison of the modelled 1980-2012 surface mass balance over the Greenland Ice Sheet

Author

Fettweis, Xavier, Hofer, Stefan, Krebs-Kanzow, Uta, Amory, Charles, Aoki, Teruo, Berends, Constantijn J., Born, Andreas, Box, Jason E., Delhasse, Alison, Fujita, Koji, Gierz, Paul, Goelzer, Heiko, Hanna, Edward, Hashimoto, Akihiro, Huybrechts, Philippe, Kapsch, Marie Luise, King, Michalea D., Kittel, Christoph, Lang, Charlotte, Langen, Peter L., Lenaerts, Jan T.M., Liston, Glen E., Lohmann, Gerrit, Mernild, Sebastian H., Mikolajewicz, Uwe, Modali, Kameswarrao, Mottram, Ruth H., Niwano, Masashi, Noël, Brice, Ryan, Jonathan C., Smith, Amy, Streffing, Jan, Tedesco, Marco, Jan Van De Berg, Willem, Van Den Broeke, Michiel, Van De Wal, Roderik S.W., Van Kampenhout, Leo, Wilton, David, Wouters, Bert, Ziemen, Florian, Zolles, Tobias, Sub Dynamics Meteorology, Proceskunde, Sub Algemeen Marine & Atmospheric Res, and Marine and Atmospheric Research

Subjects
Water Science and Technology, Earth-Surface Processes
Abstract

Observations and models agree that the Greenland Ice Sheet (GrIS) surface mass balance (SMB) has decreased since the end of the 1990s due to an increase in meltwater runoff and that this trend will accelerate in the future. However, large uncertainties remain, partly due to different approaches for modelling the GrIS SMB, which have to weigh physical complexity or low computing time, different spatial and temporal resolutions, different forcing fields, and different ice sheet topographies and extents, which collectively make an inter-comparison difficult. Our GrIS SMB model intercomparison project (GrSMBMIP) aims to refine these uncertainties by intercomparing 13 models of four types which were forced with the same ERA-Interim reanalysis forcing fields, except for two global models. We interpolate all modelled SMB fields onto a common ice sheet mask at 1 km horizontal resolution for the period 1980-2012 and score the outputs against (1) SMB estimates from a combination of gravimetric remote sensing data from GRACE and measured ice discharge; (2) ice cores, snow pits and in situ SMB observations; and (3) remotely sensed bare ice extent from MODerate-resolution Imaging Spectroradiometer (MODIS). Spatially, the largest spread among models can be found around the margins of the ice sheet, highlighting model deficiencies in an accurate representation of the GrIS ablation zone extent and processes related to surface melt and runoff. Overall, polar regional climate models (RCMs) perform the best compared to observations, in particular for simulating precipitation patterns. However, other simpler and faster models have biases of the same order as RCMs compared with observations and therefore remain useful tools for long-term simulations or coupling with ice sheet models. Finally, it is interesting to note that the ensemble mean of the 13 models produces the best estimate of the present-day SMB relative to observations, suggesting that biases are not systematic among models and that this ensemble estimate can be used as a reference for current climate when carrying out future model developments. However, a higher density of in situ SMB observations is required, especially in the south-east accumulation zone, where the model spread can reach 2 m w.e. yr-1 due to large discrepancies in modelled snowfall accumulation.

Published
2020

58. Sensitivity of Heinrich-type ice-sheet surge characteristics to boundary forcing perturbations.

Author

Schannwell, Clemens, Mikolajewicz, Uwe, Ziemen, Florian, and Kapsch, Marie-Luise

Subjects
ICE sheets, OCEAN circulation, MASS budget (Geophysics), GLACIAL melting, CLIMATE change
Abstract

Heinrich-type ice-sheet surges are one of the dominant signals of glacial climate variability. They are characterised as abrupt, quasi-periodic episodes of ice-sheet instabilities during which large amounts of ice are discharged from ice sheets into the ocean. The occurence of ice-sheet surges strongly influences the global climate evolution by altering the ocean circulation through the addition of freshwater and the atmospheric circulation through changes in ice-sheet height. The mechanisms controlling the timing and occurence of Heinrich-type ice-sheet surges remain poorly constrained to this day. Here, we use a coupled ice sheet-solid earth model to identify and quantify the importance of boundary forcing for the surge cycle length of Heinrich-type ice-sheet surges for two prominent ice streams of the Laurentide ice sheet - the land-terminating Mackenzie ice stream and the marine-terminating Hudson ice stream. We show that surface mass balance perturbations have the largest effect on the surge cycle length. Pertubations to the ice surface temperature and geothermal heatflux also influence the surge cycle length, but to a lesser degree. Ocean and sea-level forcing as well as different frequencies of the same forcing have a negligible effect on the surge cycle length. The simulations also highlight that only a certain parameter space exists under which ice-sheet oscillations can be maintained. Transitioning from an oscillatory state to a persistent ice streaming state, can result in an ice volume loss of up to 26% for the respective ice stream drainage basin under otherwise constant climate conditions. We show that Mackenzie ice stream is susceptible to undergoing such a transition in response to all tested positive climate perturbations. This underlines the potential of the Mackenzie region to have contributed to prominent abrupt climate change events of the last deglaciation. [ABSTRACT FROM AUTHOR]

Published
2022
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62. State-dependency of temperature variability in transient simulations of the last Deglaciation from models of varying complexity

Author

Ziegler, Elisa, primary, Andres, Heather, additional, Ellerhoff, Beatrice, additional, Kapsch, Marie-Luise, additional, Kutterolf, Steffen, additional, Mikolajewicz, Uwe, additional, Schindlbeck-Belo, Julie Christin, additional, Toohey, Matthew, additional, Wirths, Christian, additional, Weitzel, Nils, additional, and Rehfeld, Kira, additional

Published
2021
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71. Thermal memory of sedimentary basins: case study from the Central European Basin System

Author

Frick, Maximilian, Cacace , Mauro, Mikolajewicz, Uwe, and Scheck-Wenderoth , Magdalena

Abstract

Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ, Germany (1); Max-Planck-Institute for Meteorology, Hamburg, Germany (2); RWTH Aachen, Faculty of Georesources and Material Engineering, Aachen, Germany (3) This study deals with modelling the distribution of the subsurface temperature in space and the respective evolution in time in response to variations in the thermal boundary condition starting from the last glacial maximum (LGM, 26 ka BP). The aim here is to better understand (i) the feedback mechanisms between the atmosphere and solid earth components, and (ii) to which degree this coupling might be relevant for subsurface thermal modelling studies. The study area is the Central European Basin System (CEBS) in northern and Central Europe and state-of-the-art temperature reconstructions from the LGM to present have been used to model the surface thermal boundary conditions. Thereby, investigations on how such transient surface temperature conditions influence the temperature distribution with depth and over time within a heterogeneous sedimentary cover were carried out. The subsurface beneath the CEBS consists of more than 10 km thick sediments, which have been heavily restructured by salt movements during the whole Mesozoic evolution. Our 3D geological model resolves all major sedimentary and crustal domains, and we relied on the Max-Planck-Institute Earth System Model (MPI-ESM) temperature chronology. Starting from steady-state initial conditions, transient simulation runs are performed which cover the time from the LGM to present. Results are discussed in terms of temperature evolution over time and space. The focus will lie on quantifying subsurface conditions favourable to the establishment and maintenance of abnormally low temperature evolution and the related equilibration time within the sedimentary pile and which implications this might have for geothermal projects.

Published
2020
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74. High-resolution modelling of long-term trends in the oxygen and carbon cycles of the Benguela upwelling system.

Author

Six, Katharina D. and Mikolajewicz, Uwe

Subjects
NITROGEN cycle, OCEAN circulation, TWENTIETH century, BIOGEOCHEMISTRY, OXYGEN, SPATIAL resolution, CARBON cycle
Abstract

We investigate driving forces of the biogeochemistry of the Benguela upwelling system (BUS) and their temporal changes over the 20th century. For this purpose, we developed a global ocean-only model in a stretched grid configuration, which resolves meso-scale circulation structures in the area of interest. The biogeochemical module of this model is extended by a more comprehensive nitrogen cycle to account for the specific nitrogen loss processes common in eastern upwelling systems. The model is forced by 110 years of atmospheric reanalysis data. To assess the impact of meso-scale circulation structures on local biogeochemical processes we compare our results to a set-up with a coarser horizontal resolution, comparable to the ocean component of Earth system models used for anthropogenic climate projections. In the higher spatial resolution we find enhanced intermediate depth ventilation (200-1000 m) with concurrent reduced loss of bioavailable nitrogen and a high shelfbound biological production, in line with observations. Moreover, only in the high resolution setup do multi-decadal trends of deoxygenation match observation-based estimates. Our study supports the view that the presence of meso-scale circulation structures exerts a major influence on biogeochemical patterns, especially on mid-depth oxygen concentrations. Furthermore, we show for the first time that by including this high spatio-temporal variability of the circulation, the regional anthropogenic carbon uptake of the BUS over the 20th century is lower than in the coarse resolution model. This indicates that, at least for some regions, the pathway of changes in the marine biogeochemistry as projected by state-of-the-art coarse resolution Earth system models is associated with high uncertainty. [ABSTRACT FROM AUTHOR]

Published
2022
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83. The PMIP4-CMIP6 Last Glacial Maximum experiments: preliminary results and comparison with the PMIP3-CMIP5 simulations

Author

Kageyama, Masa, primary, Harrison, Sandy P., additional, Kapsch, Marie-L., additional, Löfverström, Marcus, additional, Lora, Juan M., additional, Mikolajewicz, Uwe, additional, Sherriff-Tadano, Sam, additional, Vadsaria, Tristan, additional, Abe-Ouchi, Ayako, additional, Bouttes, Nathaelle, additional, Chandan, Deepak, additional, LeGrande, Allegra N., additional, Lhardy, Fanny, additional, Lohmann, Gerrit, additional, Morozova, Polina A., additional, Ohgaito, Rumi, additional, Peltier, W. Richard, additional, Quiquet, Aurélien, additional, Roche, Didier M., additional, Shi, Xiaoxu, additional, Schmittner, Andreas, additional, Tierney, Jessica E., additional, and Volodin, Evgeny, additional

Published
2020
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84. Supplementary material to "GrSMBMIP: Intercomparison of the modelled 1980–2012 surface mass balance over the Greenland Ice sheet"

Author

Fettweis, Xavier, primary, Hofer, Stefan, additional, Krebs-Kanzow, Uta, additional, Amory, Charles, additional, Aoki, Teruo, additional, Berends, Constantijn J., additional, Born, Andreas, additional, Box, Jason E., additional, Delhasse, Alison, additional, Fujita, Koji, additional, Gierz, Paul, additional, Goelzer, Heiko, additional, Hanna, Edward, additional, Hashimoto, Akihiro, additional, Huybrechts, Philippe, additional, Kapsch, Marie-Luise, additional, King, Michalea D., additional, Kittel, Christoph, additional, Lang, Charlotte, additional, Langen, Peter L., additional, Lenaerts, Jan T. M., additional, Liston, Glen E., additional, Lohmann, Gerrit, additional, Mernild, Sebastian H., additional, Mikolajewicz, Uwe, additional, Modali, Kameswarrao, additional, Mottram, Ruth H., additional, Niwano, Masashi, additional, Noël, Brice, additional, Ryan, Jonathan C., additional, Smith, Amy, additional, Streffing, Jan, additional, Tedesco, Marco, additional, van de Berg, Willem Jan, additional, van den Broeke, Michiel, additional, van de Wal, Roderik S. W., additional, van Kampenhout, Leo, additional, Wilton, David, additional, Wouters, Bert, additional, Ziemen, Florian, additional, and Zolles, Tobias, additional

Published
2020
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85. GrSMBMIP: Intercomparison of the modelled 1980–2012 surface mass balance over the Greenland Ice sheet

Author

Fettweis, Xavier, primary, Hofer, Stefan, additional, Krebs-Kanzow, Uta, additional, Amory, Charles, additional, Aoki, Teruo, additional, Berends, Constantijn J., additional, Born, Andreas, additional, Box, Jason E., additional, Delhasse, Alison, additional, Fujita, Koji, additional, Gierz, Paul, additional, Goelzer, Heiko, additional, Hanna, Edward, additional, Hashimoto, Akihiro, additional, Huybrechts, Philippe, additional, Kapsch, Marie-Luise, additional, King, Michalea D., additional, Kittel, Christoph, additional, Lang, Charlotte, additional, Langen, Peter L., additional, Lenaerts, Jan T. M., additional, Liston, Glen E., additional, Lohmann, Gerrit, additional, Mernild, Sebastian H., additional, Mikolajewicz, Uwe, additional, Modali, Kameswarrao, additional, Mottram, Ruth H., additional, Niwano, Masashi, additional, Noël, Brice, additional, Ryan, Jonathan C., additional, Smith, Amy, additional, Streffing, Jan, additional, Tedesco, Marco, additional, van de Berg, Willem Jan, additional, van den Broeke, Michiel, additional, van de Wal, Roderik S. W., additional, van Kampenhout, Leo, additional, Wilton, David, additional, Wouters, Bert, additional, Ziemen, Florian, additional, and Zolles, Tobias, additional

Published
2020
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86. Developments in the MPI‐M Earth System Model version 1.2 (MPI‐ESM1.2) and Its Response to Increasing CO

Author

Mauritsen, Thorsten, Bader, Jürgen, Becker, Tobias, Behrens, Jörg, Bittner, Matthias, Brokopf, Renate, Brovkin, Victor, Claussen, Martin, Crueger, Traute, Esch, Monika, Fast, Irina, Fiedler, Stephanie, Fläschner, Dagmar, Gayler, Veronika, Giorgetta, Marco, Goll, Daniel S., Haak, Helmuth, Hagemann, Stefan, Hedemann, Christopher, Hohenegger, Cathy, Ilyina, Tatiana, Jahns, Thomas, Jimenéz‐De‐La‐Cuesta, Diego, Jungclaus, Johann, Kleinen, Thomas, Kloster, Silvia, Kracher, Daniela, Kinne, Stefan, Kleberg, Deike, Lasslop, Gitta, Kornblueh, Luis, Marotzke, Jochem, Matei, Daniela, Meraner, Katharina, Mikolajewicz, Uwe, Modali, Kameswarrao, Möbis, Benjamin, Müller, Wolfgang A., Nabel, Julia E. M. S., Nam, Christine C. W., Notz, Dirk, Nyawira, Sarah‐Sylvia, Paulsen, Hanna, Peters, Karsten, Pincus, Robert, Pohlmann, Holger, Pongratz, Julia, Popp, Max, Raddatz, Thomas Jürgen, Rast, Sebastian, Redler, Rene, Reick, Christian H., Rohrschneider, Tim, Schemann, Vera, Schmidt, Hauke, Schnur, Reiner, Schulzweida, Uwe, Six, Katharina D., Stein, Lukas, Stemmler, Irene, Stevens, Bjorn, Storch, Jin‐Song, Tian, Fangxing, Voigt, Aiko, Vrese, Philipp, Wieners, Karl‐Hermann, Wilkenskjeld, Stiig, Winkler, Alexander, and Roeckner, Erich

Subjects
Earth sciences, ddc:550
Published
2019

88. Modelling teleconnections between the North Atlantic and North Pacific during the Younger Dryas

Author

Mikolajewicz, Uwe, Crowley, Thomas J., Schiller, Andreas, and Voss, Reinhard

Subjects
North Pacific Ocean -- Natural history, Climatic changes -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The ECHAM3/LSG coupled ocean-atmosphere general circulation model has been used in a sensitivity experiment to assess the stability of the thermohaline circulation against meltwater input into the Labrador Sea. The results support a mainly atmospheric forcing of North Pacific climate variations. There is clear evidence for the influence of variations in North Atlantic Deep Water formation on the North Pacific. This can be seen as an explanation for changes in both the North Atlantic and the North Pacific in the Younger Dryas.

Published
1997

93. Ocean response to greenhouse warming

Author

Mikolajewicz, Uwe, Santer, Benjamin D., and Maier-Reimer, Ernst

Subjects
Greenhouse effect -- Research, Global warming -- Research, Sea level -- Forecasts and trends, Ocean circulation -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1990

99. The climate of a retrograde rotating Earth

Author

Mikolajewicz, Uwe, primary, Ziemen, Florian, additional, Cioni, Guido, additional, Claussen, Martin, additional, Fraedrich, Klaus, additional, Heidkamp, Marvin, additional, Hohenegger, Cathy, additional, Jimenez de la Cuesta, Diego, additional, Kapsch, Marie-Luise, additional, Lemburg, Alexander, additional, Mauritsen, Thorsten, additional, Meraner, Katharina, additional, Röber, Niklas, additional, Schmidt, Hauke, additional, Six, Katharina D., additional, Stemmler, Irene, additional, Tamarin-Brodsky, Talia, additional, Winkler, Alexander, additional, Zhu, Xiuhua, additional, and Stevens, Bjorn, additional

Published
2018
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100. Rising extreme sea levels in the German Bight under enhanced CO2 levels: a regionalized large ensemble approach for the North Sea.

Author

Lang, Andreas and Mikolajewicz, Uwe

Subjects
*SEA level, *WESTERLIES, *WIND speed, *ATMOSPHERIC models, *SEAS
Abstract

We quantify the change in extreme high sea level (ESL) statistics in the German Bight under rising CO 2 concentrations by downscaling a large ensemble of global climate model simulations using the regionally coupled climate system model REMO-MPIOM. While the model setup combines a regionally high resolution with the benefits of a global ocean model, the large ensemble size of 32 members allows the estimation of high return levels with much lower uncertainty. We find that ESLs increase with atmospheric CO 2 levels, even without considering a rise in the background sea level (BSL). Local increases of up to 0.5 m are found along the western shorelines of Germany and Denmark for ESLs of 20–50 years return periods, while higher return levels remain subject to sampling uncertainty. This ESL response is related to a cascade of an enhanced large-scale activity along the North Atlantic storm belt to a subsequent local increase in predominantly westerly wind speed extremes, while storms of the major West-Northwest track type gain importance. The response is seasonally opposite: summer ESLs and the strength of its drivers decrease in magnitude, contrasting the response of the higher winter ESLs, which governs the annual response. These results have important implications for coastal protection. ESLs do not only scale with the expected BSL rise, but become even more frequent, as preindustrial 50-year return levels could be expected to occur almost every year by the end of the century. The magnitude of the relative change in ESL statistics is hereby up to half of the expected rise in BSL, depending on the location. Changes in the highest extremes are subject to large multidecadal variations and remain uncertain, thus potentially demanding even further safety measures. [ABSTRACT FROM AUTHOR]

Published
2020
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