atmospheric composition; paleoclimate; atmospheric circulation; ice cores; biogeochemical cycles; Quaternary; greenhouse gases; aerosol; ocean temperature; Greenland; Antarctica
Lee James E., Edwards Jon S., Schmitt Jochen, Fischer Hubertus, Bock Michael, Brook Edward J. (2020), Excess methane in Greenland ice cores associated with high dust concentrations, in
Geochimica et Cosmochimica Acta, 270, 409-430.
Shackleton S., Baggenstos D., Menking J. A., Dyonisius M. N., Bereiter B., Bauska T. K., Rhodes R. H., Brook E. J., Petrenko V. V., McConnell J. R., Kellerhals T., Häberli M., Schmitt J., Fischer H., Severinghaus J. P. (2020), Global ocean heat content in the Last Interglacial, in
Nature Geoscience, 13(1), 77-81.
Erhardt Tobias, Jensen Camilla M., Borovinskaya Olga, Fischer Hubertus (2019), Single Particle Characterization and Total Elemental Concentration Measurements in Polar Ice Using Continuous Flow Analysis-Inductively Coupled Plasma Time-of-Flight Mass Spectrometry, in
Environmental Science & Technology, 53(22), 13275-13283.
Fischer Hubertus, Schmitt Jochen, Bock Michael, Seth Barbara, Joos Fortunat, Spahni Renato, Lienert Sebastian, Battaglia Gianna, Stocker Benjamin D., Schilt Adrian, Brook Edward J. (2019), N2O changes from the Last Glacial Maximum to the preindustrial – Part 1: Quantitative reconstruction of terrestrial and marine emissions using N2O stable isotopes in ice cores, in
Biogeosciences, 16(20), 3997-4021.
Gottschalk Julia, Battaglia Gianna, Fischer Hubertus, Frölicher Thomas L., Jaccard Samuel L., Jeltsch-Thömmes Aurich, Joos Fortunat, Köhler Peter, Meissner Katrin J., Menviel Laurie, Nehrbass-Ahles Christoph, Schmitt Jochen, Schmittner Andreas, Skinner Luke C., Stocker Thomas F. (2019), Mechanisms of millennial-scale atmospheric CO2 change in numerical model simulations, in
Quaternary Science Reviews, 220, 30-74.
Baggenstos Daniel, Häberli Marcel, Schmitt Jochen, Shackleton Sarah A., Birner Benjamin, Severinghaus Jeffrey P., Kellerhals Thomas, Fischer Hubertus (2019), Earth’s radiative imbalance from the Last Glacial Maximum to the present, in
Proceedings of the National Academy of Sciences, 116(30), 14881-14886.
Joos Fortunat, Battaglia Gianna, Fischer Hubertus, Jeltsch-Thömmes Aurich, Schmitt Jochen (2019), Marine N2O emissions during a Younger Dryas-like event: the role of meridional overturning, tropical thermocline ventilation, and biological productivity, in
Environmental Research Letters, 14(7), 075007-075007.
Erhardt Tobias, Capron Emilie, Rasmussen Sune Olander, Schüpbach Simon, Bigler Matthias, Adolphi Florian, Fischer Hubertus (2019), Decadal-scale progression of the onset of Dansgaard–Oeschger warming events, in
Climate of the Past, 15(2), 811-825.
Burgay François, Erhardt Tobias, Lunga Damiano Della, Jensen Camilla Marie, Spolaor Andrea, Vallelonga Paul, Fischer Hubertus, Barbante Carlo (2019), Fe2+ in ice cores as a new potential proxy to detect past volcanic eruptions, in
Science of The Total Environment, 654, 1110-1117.
Eichler Jan, Weikusat Christian, Wegner Anna, Twarloh Birthe, Behrens Melanie, Fischer Hubertus, Hörhold Maria, Jansen Daniela, Kipfstuhl Sepp, Ruth Urs, Wilhelms Frank, Weikusat Ilka (2019), Impurity Analysis and Microstructure Along the Climatic Transition From MIS 6 Into 5e in the EDML Ice Core Using Cryo-Raman Microscopy, in
Frontiers in Earth Science, 7(20), 1-16.
Han Changhee, Do Hur Soon, Han Yeongcheol, Lee Khanghyun, Hong Sungmin, Erhardt Tobias, Fischer Hubertus, Svensson Anders M., Steffensen Jørgen Peder, Vallelonga Paul (2018), High-resolution isotopic evidence for a potential Saharan provenance of Greenland glacial dust, in
Scientific Reports, 8(1), 15582-15582.
Schüpbach S., Fischer H., Bigler M., Erhardt T., Gfeller G., Leuenberger D., Mini O., Mulvaney R., Abram N. J., Fleet L., Frey M. M., Thomas E., Svensson A., Dahl-Jensen D., Kettner E., Kjaer H., Seierstad I., Steffensen J. P., Rasmussen S. O., Vallelonga P., Winstrup M., Wegner A., Twarloh B., Wolff K., et al. (2018), Greenland records of aerosol source and atmospheric lifetime changes from the Eemian to the Holocene, in
Nature Communications, 9(1), 1476-1476.
Beck Jonas, Bock Michael, Schmitt Jochen, Seth Barbara, Blunier Thomas, Fischer Hubertus (2018), Bipolar carbon and hydrogen isotope constraints on the Holocene methane budget, in
Biogeosciences, 15(23), 7155-7175.
Adolphi Florian, Bronk Ramsey Christopher, Erhardt Tobias, Edwards R. Lawrence, Cheng Hai, Turney Chris S. M., Cooper Alan, Svensson Anders, Rasmussen Sune O., Fischer Hubertus, Muscheler Raimund (2018), Connecting the Greenland ice-core and U∕Th timescales via cosmogenic radionuclides: testing the synchroneity of Dansgaard–Oeschger events, in
Climate of the Past, 14(11), 1755-1781.
Fischer Hubertus, Meissner Katrin J., Mix Alan C., Abram Nerilie J., Austermann Jacqueline, Brovkin Victor, Capron Emilie, Colombaroli Daniele, Daniau Anne-Laure, Dyez Kelsey A., Felis Thomas, Finkelstein Sarah A., Jaccard Samuel L., McClymont Erin L., Rovere Alessio, Sutter Johannes, Wolff Eric W., Affolter Stéphane, Bakker Pepijn, Ballesteros-Cánovas Juan Antonio, Barbante Carlo, Caley Thibaut, Carlson Anders E., Churakova Olga, et al. (2018), Palaeoclimate constraints on the impact of 2 °C anthropogenic warming and beyond, in
Nature Geoscience, 11(7), 474-485.
Umezawa Taku, Brenninkmeijer Carl A. M., Röckmann Thomas, van der Veen Carina, Tyler Stanley C., Fujita Ryo, Morimoto Shinji, Aoki Shuji, Sowers Todd, Schmitt Jochen, Bock Michael, Beck Jonas, Fischer Hubertus, Michel Sylvia E., Vaughn Bruce H., Miller John B., White James W. C., Brailsford Gordon, Schaefer Hinrich, Sperlich Peter, Brand Willi A., Rothe Michael, Blunier Thomas, Lowry David, et al. (2018), Interlaboratory comparison of d13C and dD measurements of atmospheric CH4 for combined use of data sets from different laboratories, in
Atmospheric Measurement Techniques, 11(2), 1207-1231.
Bohleber Pascal, Erhardt Tobias, Spaulding Nicole, Hoffmann Helene, Fischer Hubertus, Mayewski Paul (2018), Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium, in
Climate of the Past, 14(1), 21-37.
Parrenin Frédéric, Cavitte Marie G. P., Blankenship Donald D., Chappellaz Jérôme, Fischer Hubertus, Gagliardini Olivier, Masson-Delmotte Valérie, Passalacqua Olivier, Ritz Catherine, Roberts Jason, Siegert Martin J., Young Duncan A. (2017), Is there 1.5-million-year-old ice near Dome C, Antarctica?, in
The Cryosphere, 11(6), 2427-2437.
Bock Michael, Schmitt Jochen, Beck Jonas, Seth Barbara, Chappellaz Jérôme, Fischer Hubertus (2017), Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH 4 ice core records, in
Proceedings of the National Academy of Sciences, 114(29), E5778-E5786.
Köhler Peter, Nehrbass-Ahles Christoph, Schmitt Jochen, Stocker Thomas F., Fischer Hubertus (2017), A 156 kyr smoothed history of the atmospheric greenhouse gases CO2, CH4, and N2O and their radiative forcing, in
Earth System Science Data, 9(1), 363-387.
Dyonisius M.N., Petrenko V.V., Smith A.M., Hua W., Yang B., Schmitt J., Beck J., Seth B., Bock M., Hmiel B., Vimont I., Menking J.A., Shackleton S.A., Baggenstos D., Bauska T.K., Rhodes R.H., Sperlich P., Beaudette R., Harth C., Kalk M., Brook E.J., Fischer H., Severinghaus J.P., Weiss R.F., Old carbon reservoirs were not important in the deglacial methane budget, in
Science.
Bipolar Holocene Composite Ice Core CH4, d13C, and dD Data
| Author |
Beck, J.; Bock, M.; Schmitt, J.; Seth, B.; Blunier, T.; Fischer, H. |
| Publication date |
07.12.2018 |
| Persistent Identifier (PID) |
noaa-icecore-25350 |
| Repository |
NOAA Paleoclimate Data Base
|
| Abstract |
Ice core Holocene composite Northern (GISP2, GRIP, and NGRIP) and Southern (WAIS, TALDICE, EDC) Hemisphere methane (CH4), carbon isotope (d13C), and hydrogen isotope (dD) data
| Author |
Köhler, P.; Nehrbass-Ahles, C.; Schmitt, J.; Stocker, T.F.; Fischer, H. |
| Publication date |
20.07.2017 |
| Persistent Identifier (PID) |
https://doi.org/10.1594/PANGAEA.871273 |
| Repository |
PANGAEA
|
| Abstract |
Continuous records of the atmospheric greenhouse gases (GHGs) CO2, CH4, and N2O are necessary input data for transient climate simulations and their related radiative forcing important components in analyses of climate sensitivity and feedbacks. Since the available data from ice cores are discontinuous and partly ambiguous a well-documented decision process during data compilation followed by some interpolating post-processing are necessary to obtain those desired time series. Here we document our best-guess data compilation of published ice core records and recent measurements on firn air and atmospheric samples covering the time window from the penultimate glacial maximum (approx. 156 kyr BP) to 2016 CE. A smoothing spline method is applied to translate the discrete and irregularly spaced data points into continuous time series. These splines are assumed to represent the evolution of the atmospheric mixing ratios for the three GHGs. Global-mean radiative forcing for each GHG is computed using well-established, simple formulations. Newest published age scales are used for the ice core data. While CO2 is representing an integrated global signal, we compile only a southern hemisphere record of CH4 and identify how much larger a northern hemisphere or global CH4 record might have been due to its interhemispheric gradient. Data resolution and uncertainties are considered in the spline procedure and typical cutoff periods, defining the degree of smoothing, range from 5000 years for the less resolved older parts of the records to 4 years for the densely-sampled recent years. The data sets describe seamlessly the GHG evolution on orbital and millennial time scales for glacial and glacial-interglacial variations and on centennial and decadal time scales for anthropogenic times.
| Author |
Erhardt, T.; Capron, E.; Rasmussen, S.O.; Schüpbach, S.; Bigler, M.; Adolphi, F.; Fischer, H. |
| Publication date |
25.04.2019 |
| Persistent Identifier (PID) |
https://doi.org/10.1594/PANGAEA.896743 |
| Repository |
PANGAEA
|
| Abstract |
Decadal averages of the NEEM aerosol data for sodium and calcium, both measured by continuous flow analysis (CFA). Decadal averages of the NGRIP aerosol data for sodium and calcium, both measured by continuous flow analysis (CFA). High resolution aerosol, layer thickness and d18O data around Greenland warming events (10-60ka) from NGRIP and NEEM ice cores
| Author |
Baggenstos, D.; Häberli, M.; Schmitt, J.; Shackleton, S.A.; Birner, B.; Severinghaus, J.P.; Kellerhals, T.; Fischer, H. |
| Publication date |
04.06.2019 |
| Persistent Identifier (PID) |
https://www.pnas.org/content/suppl/2019/07/02/1905447116.DCSupplemental |
| Repository |
PNAS
|
| Abstract |
Planetary Radiative Imbalance for the Deglaciation and the Holocene derived from the EDC/WD Ocean Heat Content record and the Lambeck et al. (2014) sea level compilation. Not HID corrected.
| Author |
Bock, M.; Schmitt, J.; Beck, J.; Seth, B.; Chappellaz, J.; Fischer, H. |
| Publication date |
01.06.2017 |
| Persistent Identifier (PID) |
https://doi.pangaea.de/10.1594/PANGAEA.873918 |
| Repository |
PANGAEA
|
| Abstract |
Atmospheric methane (CH4) records reconstructed from polar ice cores represent a integrated view on processes predominantly taking place in the terrestrial biogeosphere. Here we present dual stable isotopic methane records (d13CH4 and dD(CH4)) from four Antarctic ice cores, which provide improved constraints on past changes in natural methane sources. Our isotope data show that tropical wetlands and seasonally inundated floodplains are most likely the controlling sources of atmospheric methane variations for the current and two older interglacials and their preceding glacial maxima. The changes in these sources are steered by variations in temperature, precipitation and the water table, as modulated by insolation, (local) sea level and monsoon intensity. Based on our new dD(CH4) constraint, it appears that geologic emissions of methane may play a steady but only minor role in atmospheric CH4 changes, and that the glacial budget is not dominated by these sources. Superimposed on the glacial/interglacial variations is a marked difference in both isotope records, with systematically higher values during the last 25,000 years compared to older time periods. This shift cannot be explained by climatic changes. Rather, our isotopic methane budget points to a marked increase in fire activity, possibly due to biome changes and accumulation of fuel related to the late Pleistocene megafauna extinction, which took place in the course of the last glacial.
| Author |
Schüpbach, S.; Fischer, H.; Bigler, M.; Erhardt, T.; Gfeller, G.; Leuenberger, D.; Mini, O. |
| Publication date |
16.04.2018 |
| Persistent Identifier (PID) |
https://www.nature.com/articles/s41467-018-03924-3#Sec11 |
| Repository |
Nature Communications
|
| Abstract |
File Name: Supplementary Data 1Description: NEEM ion concentration data in 10 yr resolution.File Name: Supplementary Data 2Description: Aerosol source concentrations and atmospheric lifetime in 10 yr resolutionderived from the NEEM ice core data.
| Author |
Gottschalk, J.; Battaglia, G.; Fischer, H.; Frölicher, T.L.; Jaccatd, S.L.; Jeltsch-Thömmes, A.; Joos, F.; Köhler, P.; Meissner, K.; Menviel, L.; Nehrbass-Ahles, C.; Schmitt, J.; Schmittner, A.; Skinner, L.C.; Stocker, T.F. |
| Publication date |
15.05.2016 |
| Persistent Identifier (PID) |
https://doi.org/10.1016/j.quascirev.2019.05.013. |
| Repository |
Quaternary Science reviews
|
| Abstract |
Numerical models are important tools for understanding the processes and feedbacks in the Earth system, including those involving changes in atmospheric CO2 (CO2,atm) concentrations. Here, we compile 55 published model studies (consisting of 778 individual simulations) that assess the impact of six forcing mechanisms on millennial-scale CO2,atm variations: changes in freshwater supply to the North Atlantic and Southern Ocean, the strength and position of the southern-hemisphere westerlies, Antarctic sea ice extent, and aeolian dust fluxes. We generally find agreement on the direction of simulated CO2,atm change across simulations, but the amplitude of change is inconsistent, primarily due to the different complexities of the model representation of Earth system processes. When freshwater is added to the North Atlantic, a reduced Atlantic Meridional Overturning Circulation (AMOC) is generally accompanied by an increase in Southern Ocean- and Pacific overturning, reduced Antarctic sea ice extent, spatially varying export production, and changes in carbon storage in the Atlantic (rising), in other ocean basins (generally decreasing) and on land (more varied). Positive or negative CO2,atm changes are simulated during AMOC minima due to a spatially and temporally varying dominance of individual terrestrial and oceanic drivers (and compensating effects between them) across the different models. In contrast, AMOC recoveries are often accompanied by rising CO2,atm levels, which are mostly driven by ocean carbon release (albeit from different regions). The magnitude of simulated CO2,atm rise broadly scales with the duration of the AMOC perturbation (i.e., the stadial length). When freshwater is added to the Southern Ocean, reduced deep-ocean ventilation drives a CO2,atm drop via reduced carbon release from the Southern Ocean. Although the impacts of shifted southern-hemisphere westerlies are inconsistent across model simulations, their intensification raises CO2,atm via enhanced Southern Ocean Ekman pumping. Increased supply of aeolian dust to the ocean, and thus iron fertilisation of marine productivity, consistently lowers modelled CO2,atm concentrations via more efficient nutrient utilisation. The magnitude of CO2,atm change in response to dust flux variations, however, largely depends on the complexity of models' marine ecosystem and iron cycle. This especially applies to simulations forced by Antarctic sea ice changes, in which the direction of simulated CO2,atm change varies greatly across model hierarchies. Our compilation highlights that no single (forcing) mechanism can explain observed past millennial-scale CO2,atm variability, and identifies important future needs in coupled carbon cycle-climate modelling to better understand the mechanisms governing CO2,atm changes in the past.
| Author |
Bohleber, P.; Erhardt, T.; Spaulding, N.; Hoffmann, H.; Fischer, H., H.; Mayewski, P. |
| Publication date |
10.01.2018 |
| Persistent Identifier (PID) |
https://doi.org/10.1594/PANGAEA.883521 |
| Repository |
PANGAEA
|
| Abstract |
Among ice core drilling sites in the European Alps, Colle Gnifetti (CG) is the only non-temperate glacier to offer climate records back to at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. However, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighboring ice core, we explore the time series of stable water isotopes and the mineral dust proxies Ca2+ and insoluble particles. Also in our latest ice core we face the already known limitation to the quantitative use of the stable isotope variability based on a high and potentially non-stationary isotope/temperature sensitivity at CG. Decadal trends in Ca2+ reveal substantial agreement with instrumental temperature and are explored here as a potential site-specific supplement to the isotope-based temperature reconstruction. The observed coupling between temperature and Ca2+-trends likely results from snow preservation effects and the advection of dust-rich air masses coinciding with warm temperatures.We find that if calibrated against instrumental data, the Ca2+-based temperature reconstruction is in robust agreement with the latest proxy-based summer temperature reconstruction, including a "Little Ice Age" cold period as well as a medieval climate anomaly. Part of the medieval climate period around 1100-1200 AD clearly stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and/or dry conditions over the Mediterranean.
Polar Ice Core 28,000 Year Nitrous Oxide Isotope Data
| Author |
Fischer, Hubertus; Schmitt, Jochen; Bock, Michael; Seth, Barbara; Joos, Fortunat; Spahni, Renato; Lienert, Sebastian; Battaglia, Gianna; Stocker, Benjamin D.; Schilt, Adrian; Brook, Ed J. |
| Publication date |
31.01.2020 |
| Persistent Identifier (PID) |
noaa-icecore-28890 |
| Repository |
NOAA Paleoclimate Dtabase
|
| Abstract |
Polar ice core nitrous oxide concentration and isotope (d15N and d18O) data of N2O from the TALDICE, EDML, and NGRIP ice cores, for the past 28,000 years, plus derived emission fluxes
Paleoclimate studies on polar ice cores provide a wealth of climate and atmospheric information, with the documentation of greenhouse gas concentrations and hence radiative forcing changes being amongst the most prominent examples. The latest analytical developments in ice core research in my group allow for a more detailed and quantitative process understanding of past changes in climate and biogeochemical cycles and the feedbacks between them. The objective of iCEP is to extend these new techniques and apply them to new and existing ice cores. This comprises A) the quantification of source emissions and processes responsible for the change in greenhouse gas concentrations, B) the reconstruction of environmental changes outside the ice sheets using ice core aerosol records and C) the quantification of changes in the ocean heat budget and hence temperature changes on a global scale. A special focus of these 3 topics will be the study of past interglacials over the last 800,000 years to understand the reasons for their different strength of warming and to improve our knowledge of climate/biogeochemical coupling during warm climates. Within iCEP we will apply the worldwide unique capability in my group to measure the full suite of stable isotopes of greenhouse gases in ice cores (d13CO2, d18O(CO2), d13CH4, dD(CH4), d15N2O, d18O(N2O) to selected ice core intervals in order to gain a deeper process understanding of past changes in the biogeochemical cycles and to constrain the source budget of these greenhouse gases. We will use the comprehensive multiparameter aerosol tracer information derived from Continuous Flow Analyses (CFA) to assess temporal changes in the source strength and transport and, thus, environmental conditions away from the ice sheets. A special focus within iCEP will be CFA analyses on the ongoing EGRIP ice core drilling to obtain the first complete Holocene aerosol record in seasonal resolution. Finally, measurements of noble gas isotopic and elemental ratios in ice cores will allow us to reconstruct Global Mean Ocean Temperature (GMOT) using a novel noble gas solubility thermometer. This will also provide unique information on ocean heat uptake or release during long-term transient climate changes. Synthesis of these three quantitative strains of paleoclimate information with other ice core records, other paleoclimate archives and climate model output will enhance our understanding of past and future changes in the Earth System.