A5026393193- Atmospheric and Environmental Gas Dynamics
- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Methane Hydrates and Related Phenomena
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Hydrocarbon exploration and reservoir analysis
- Isotope Analysis in Ecology
- Analytical Chemistry and Chromatography
- Polar Research and Ecology
- Analytical Methods in Pharmaceuticals
- Solar and Space Plasma Dynamics
- Climate change and permafrost
- Climate variability and models
- Ionosphere and magnetosphere dynamics
- Pleistocene-Era Hominins and Archaeology
- Winter Sports Injuries and Performance
- Air Quality Monitoring and Forecasting
- Natural product bioactivities and synthesis
- Synthesis and Reactivity of Heterocycles
- Free Radicals and Antioxidants
- Electron Spin Resonance Studies
- Plant biochemistry and biosynthesis
- Radioactive contamination and transfer
- Chromatography in Natural Products
University of Rochester
2016-2025
St. Petersburg State Technological Institute
2017
Institute of Arctic and Alpine Research
2006-2014
University of Colorado Boulder
2006-2014
University of California, San Diego
2005-2013
Scripps Institution of Oceanography
2005-2013
Centre National de la Recherche Scientifique
2012
Laboratoire de Glaciologie et Géophysique de l’Environnement
2012
GIPSA-Lab
2012
University of Arizona
2007
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...
Abstract. Air was sampled from the porous firn layer at NEEM site in Northern Greenland. We use an ensemble of ten reference tracers known atmospheric history to characterise transport properties site. By analysing uncertainties both data and gas histories, we can objectively assign weights each gases used for depth-diffusivity reconstruction. define objective root mean square criterion that is minimised model tuning procedure. Each tracer constrains profile differently through its unique...
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...
The cause of a large increase atmospheric methane concentration during the Younger Dryas-Preboreal abrupt climatic transition (approximately 11,600 years ago) has been subject much debate. carbon-14 (14C) content (14CH4) should distinguish between wetland and clathrate contributions to this increase. We present measurements 14CH4 in glacial ice, targeting transition, performed by using ice samples obtained from an ablation site west Greenland. Measured values were higher than predicted under...
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...
We report atmospheric methane carbon isotope ratios (delta13CH4) from the Western Greenland ice margin spanning Younger Dryas-to-Preboreal (YD-PB) transition. Over recorded approximately 800 years, delta13CH4 was around -46 per mil (per thousand); that is, 1 thousand higher than in modern atmosphere and 5.5 would be expected budgets without 13C-rich anthropogenic emissions. This requires natural emissions or stronger sink fractionation conventionally assumed. Constant during rise...
Abstract. We present the first reconstruction of Northern Hemisphere (NH) high latitude atmospheric carbon monoxide (CO) mole fraction from Greenland firn air. Firn air samples were collected at three deep ice core sites in (NGRIP 2001, Summit 2006 and NEEM 2008). CO records agree well with each other as recent measurements, indicating that is preserved these sites. history was reconstructed back to year 1950 measurements using a combination two forward models gas transport an inverse model....
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. We reconstruct atmospheric abundances of the potent greenhouse gas c-C4F8 (perfluorocyclobutane, perfluorocarbon PFC-318) from measurements in situ, archived, firn, and aircraft air samples with precisions ∼1 %–2 % reported on SIO-14 gravimetric calibration scale. Combined inverse methods, we found near-zero early 1900s to 1960s, after which they rose sharply, reaching 1.66 ppt (parts per trillion dry-air mole fraction) 2017. Global emissions near zero 1960s 1.2±0.1 (1σ) Gg yr−1...
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...
Abstract. We present a 60-year record of the stable isotopes atmospheric carbon monoxide (CO) from firn air samples collected under framework North Greenland Eemian Ice Drilling (NEEM) project. CO concentration, δ13C, and δ18O were measured by gas chromatography/isotope ratio mass spectrometry (gc-IRMS) trapped gases in firn. applied LGGE-GIPSA models (Witrant et al., 2011) to correlate age with depth then reconstructed trend its isotopic composition at high northern latitudes since 1950....
Abstract. The short-chain non-methane hydrocarbons (NMHC) are mostly emitted into the atmosphere by anthropogenic processes. Recent studies have pointed out a tight linkage between atmospheric mole fractions of NMHC ethane and growth rate methane. Consequently, valuable indicators for tracking changes in emissions, photochemical ozone production, greenhouse gases. This study investigates 1950–2010 Northern Hemisphere C2–C5 ethane, propane, i-butane, n-butane, i-pentane, n-pentane (a)...
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. 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. Carbon monoxide (CO) is a regulated pollutant and one of the key components determining oxidizing capacity atmosphere. Obtaining reliable record atmospheric CO mixing ratios ([CO]) since preindustrial times necessary to evaluate climate–chemistry models under conditions different from today constrain past sources. We present high-resolution measurements ice cores drilled at five sites on Greenland sheet that experience range snow accumulation rates, mean surface temperatures,...
Abstract. Global chemistry–climate models (CCMs) play an important role in assessing the climate and air pollution implications of aerosols chemically reactive gases. Evaluating these under past conditions constraining historical sources sinks necessitate reliable records atmospheric mixing ratios spanning preindustrial times. Such precious were recently obtained for carbon monoxide (CO), documenting first time evolution this compound over industrial era. In study, we compare simulated...
Abstract The global CH 4 budget of sources and sinks is highly uncertain, particularly the emissions from specific such as fossil fuels (FF) or agriculture. Here, we estimate plausible source sink scenarios using historical observations simulations atmospheric mole fraction its stable isotopic ( δ 13 C‐CH , D‐CH ) radiocarbon (Δ 14 composition, combining constraints all these tracers for first time. We employ a one‐box model along with Monte Carlo particle filter technique, explicitly...
Abstract Carbonyl sulfide (COS) was measured in firn air collected during seven different field campaigns carried out at four sites Greenland and Antarctica between 2001 2015. A Bayesian probabilistic statistical model is used to conduct multisite inversions reconstruct separate atmospheric histories for Antarctica. The cover most of the 20th century over extend back 19th derived are consistent with independent surface time series data from corresponding Antarctic ice core COS records...
Abstract. Compacted snow (firn) preserves a continuous record of atmospheric composition up to century back in time. Firn air transport modeling is essential for interpretation firn gas records. Each site needs be characterised individually through tuning procedure, which the effective diffusivity at each depth adjusted optimise agreement between modeled and measured mixing ratios selected reference (usually CO2). We present characterisation NEEM site, Northern Greenland (77.45° N 51.06° W),...