A5017409304- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Polar Research and Ecology
- Climate variability and models
- Isotope Analysis in Ecology
- Atmospheric chemistry and aerosols
- Winter Sports Injuries and Performance
- Hydrocarbon exploration and reservoir analysis
- Pleistocene-Era Hominins and Archaeology
- Nuclear Physics and Applications
- Paleontology and Stratigraphy of Fossils
- Geological and Geophysical Studies
- Geomagnetism and Paleomagnetism Studies
- Atmospheric Ozone and Climate
- Climate change and permafrost
- Planetary Science and Exploration
- Meteorological Phenomena and Simulations
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Nuclear physics research studies
- Radiation Therapy and Dosimetry
- High Altitude and Hypoxia
Oeschger Centre for Climate Change Research
2019-2024
University of Bern
2017-2024
Australian Antarctic Division
2022-2024
University of Tasmania
2024
Scripps Institution of Oceanography
2013-2020
University of California, San Diego
2013-2020
Federal Office of Meteorology and Climatology MeteoSwiss
2008
Abstract. The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep that provides climate records of the past ∼68 ka at unprecedented temporal resolution. upper 2850 m (back to 31.2 BP) have been dated using annual-layer counting. Here we present chronology for part (67.8–31.2 BP), which based on stratigraphic matching annual-layer-counted Greenland cores globally well-mixed atmospheric methane. We calculate WD gas age–ice age difference (Δage)...
An understanding of the mechanisms that control CO2 change during glacial-interglacial cycles remains elusive. Here we help to constrain changing sources with a high-precision, high-resolution deglacial record stable isotopic composition carbon in CO2(δ(13)C-CO2) air extracted from ice samples Taylor Glacier, Antarctica. During initial rise atmospheric 17.6 15.5 ka, these data demarcate decrease δ(13)C-CO2, likely due weakened oceanic biological pump. From 11.5 continued 40 ppm is associated...
Significance Cold and dry glacial-state climate conditions persisted in the Southern Hemisphere until approximately 17.7 ka, when paleoclimate records show a largely unexplained sharp, nearly synchronous acceleration deglaciation. Detailed measurements Antarctic ice cores document exactly at that time unique, ∼192-y series of massive halogen-rich volcanic eruptions geochemically attributed to Mount Takahe West Antarctica. Rather than coincidence, we postulate halogen-catalyzed stratospheric...
Significance Earth’s radiative imbalance determines whether energy is flowing into or out of the ocean–atmosphere system. The present, anthropogenic, positive drives global warming. This study reconstructs for last deglaciation, ∼20,000 to 10,000 y ago. During a was maintained several thousand years, which brought climate system from ice age Holocene warm period. We show that varied significantly during this time, possibly due changes in ocean circulation affect fluxes, highlighting...
Permafrost and methane hydrates are large, climate-sensitive old carbon reservoirs that have the potential to emit large quantities of methane, a potent greenhouse gas, as Earth continues warm. We present ice core isotopic measurements (Δ14C, δ13C, δD) from last deglaciation, which is partial analog for modern warming. Our results show emissions in response deglacial warming were small (<19 teragrams per year, 95% confidence interval) argue against similar future also indicate biomass...
Abstract The ocean's immense ability to store and release heat on centennial millennial time scales modulates the impacts of climate perturbations. To gain a better understanding past variations in mean ocean temperature (MOT), noble gas‐based proxy measured from ancient air ice cores has been developed. Here we assess non‐temperature effects that may influence atmospheric gas ratios reconstructed polar how they impact signal with an intermediate complexity Earth system model. We find...
Significance Past variations in Earth’s climate and atmospheric composition are recorded accumulating polar meteoric ice the air trapped within it. Ice outcrops provide accessible archives of old but difficult to date reliably. Here we demonstrate 81 Kr radiometric dating ice, allowing accurate up 1.5 million-year-old ice. The technique successfully identifies valuable from previous interglacial period at Taylor Glacier, Antarctica. Our method will enhance scientific value outcropping sites...
Abstract Interpretation of ice core trace gas records depends on an accurate understanding the processes that smooth atmospheric signal in firn. Much work has been done to understand affecting air transport open pores firn, but a paucity data from trapped bubbles firn‐ice transition region limited ability constrain effect bubble closure processes. Here we present high‐resolution measurements firn density, methane concentrations, nitrogen isotopes, and total content show layering at West...
Abstract Ice core records from Antarctica show mostly synchronous temperature variations during the last deglacial transition, an indication that climate of entire continent reacted as one unit to global changes. However, a record Taylor Dome ice in Ross Sea sector East has been suggested rapid warming, similar style and with Oldest Dryas—Bølling warming Greenland. Since publication record, number lines evidence have this interpretation is incorrect reflects errors underlying time scale. The...
Nitrogen trifluoride (NF(3)) has potential to make a growing contribution the Earth's radiative budget; however, our understanding of its atmospheric burden and emission rates been limited. Based on revision previous calibration using an expanded set measurements together with model inverse method, we estimate that global emissions NF(3) in 2011 were 1.18 ± 0.21 Gg⋅y(-1), or ∼20 Tg CO(2)-eq⋅y(-1) (carbon dioxide equivalent based 100-y warming 16,600 for NF(3)). The mean tropospheric dry air...
Abstract. Deglaciations are characterized by relatively fast and near-synchronous changes in ice sheet volume, ocean temperature, atmospheric greenhouse gas concentrations, but glacial inception occurs more gradually. Understanding the evolution of sheet, ocean, atmosphere conditions from interglacial to maximum provides insight into interplay these components climate system. Using noble measurements ancient samples, we reconstruct mean temperature (MOT) 74 59.7 ka, covering Marine Isotope...
The ocean is the largest heat reservoir of planet active on millennial to orbital time scales. By observing and reconstructing its temperature changes &#8211; together with evolution ice sheet volume insights distribution Earth&#8217;s energy balance may be traced though (Baggenstos et al., 2019).MOT reconstructed in our studies from noble gases trapped within cores. Noble are inert: as a result, they partition simple two reservoirs system: atmosphere not affected by biological...
The aim of the Australian Million Year Ice Core Project (MYIC) is to drill and recover an ice core that extends well over a million years ago. Due highly thinned nature close bedrock MYIC, good vertical sampling resolution, thus small sample capabilities, key resolve variability in climate records. This requirement demands major development new measurement capability, including state-of-the-art continuous flow analysis facility build gas laboratory.The main capabilities for laboratory...
Abstract During deglaciations, Earth takes up vast amounts of energy, about half which heats the global ocean. Thus, ocean heat content (OHC) is a key metric to assess Earth's energy budget. Recent modeling studies suggest that OHC changes not only in response orbitally driven climate change but also modulated on millennial timescales by Atlantic Meridional Overturning Circulation (AMOC). Here, we present first record for last four deglaciations using noble‐gas ratios EPICA Dome C ice core....
Abstract Changes in atmospheric CO 2 on millennial‐to‐centennial timescales are key components of past climate variability during the last glacial and deglacial periods (70–10 ka), yet sources mechanisms responsible for fluctuations remain largely obscure. Here we report 13 C/ 12 C ratio a interval period at submillennial resolution, with coeval histories , CH 4 N O concentrations. The carbon isotope data suggest that millennial‐scale Marine Isotope Stage 3 is driven by changes organic...
Abstract Noble gases in ice cores enable reconstructions of past mean ocean temperature. A recent result from the clathrate‐containing WAIS Divide Ice Core showed tight covariation between and Antarctic temperatures throughout last deglaciation, except for Younger Dryas interval. In beginning this interval, oceans warmed at 2.5 °C/kyr—three times greater than estimates modern warming. If valid, challenges our understanding mechanisms controlling heat uptake. Here we reconstruct temperature...
Abstract. New ice cores retrieved from the Taylor Glacier (Antarctica) blue area contain and air spanning Marine Isotope Stage (MIS) 5–4 transition, a period of global cooling sheet expansion. We determine chronologies for bubbles in new by visually matching variations gas- ice-phase tracers to preexisting core records. The reveal an age–gas age difference (Δage) approaching 10 ka during MIS 4, implying very low snow accumulation zone. A revised chronology analogous section Dome (84 55 ka),...
Abstract Monthly forecasting bridges the gap between medium-range weather and seasonal predictions. While such forecasts in prediction range of 1–4 weeks are vital to many applications context climate risk management, surprisingly little has been published on actual monthly skill existing global circulation models. Since 2004, European Centre for Medium-Range Weather Forecasts operationally run a dynamical system (MOFC). It is aim this study provide systematic fully probabilistic evaluation...
Abstract. Marine sediments, speleothems, paleo-lake elevations, and ice core methane δ18O of O2 (δ18Oatm) records provide ample evidence for repeated abrupt meridional shifts in tropical rainfall belts throughout the last glacial cycle. To improve understanding impact events on global terrestrial biosphere, we present composite δ18Oatm inferred changes fractionation by biosphere (ΔεLAND) from discrete gas measurements WAIS Divide (WD) Siple Dome (SD) Antarctic cores. On common WD timescale,...
Abstract. Together with the latent heat stored in glacial ice sheets, ocean uptake carries lion's share of glacial–interglacial changes planetary content, but little direct information on global mean temperature (MOT) is available to constrain response climate perturbations. Using ratios noble gases and molecular nitrogen trapped Antarctic EPICA Dome C core, we are able reconstruct MOT for peak interglacial conditions during last 700 000 years explore differences between these extrema. To...