A5089214529- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Arctic and Antarctic ice dynamics
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Climate change and permafrost
- Hydrocarbon exploration and reservoir analysis
- Marine and coastal ecosystems
- History and advancements in chemistry
- Isotope Analysis in Ecology
- Cryospheric studies and observations
- Geological Studies and Exploration
- Radioactive element chemistry and processing
- Air Quality Monitoring and Forecasting
- Astronomical and nuclear sciences
- Nuclear Physics and Applications
- Radioactive contamination and transfer
- Lanthanide and Transition Metal Complexes
- Geology and Paleoclimatology Research
- Meteorological Phenomena and Simulations
- Oceanographic and Atmospheric Processes
- Geochemistry and Elemental Analysis
- Spectroscopy and Laser Applications
- Advanced Frequency and Time Standards
- Chemical Reactions and Isotopes
Stockholm University
2015-2024
Bolin Centre for Climate Research
2015-2024
Middlesex University
2018
Worcester Polytechnic Institute
2017
Yale University
2017
University of Colorado Boulder
2003-2007
Newcastle University
1971
Abstract. Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions concentrations of CH4 continue increase, making second most human-influenced greenhouse gas in terms forcing, after carbon dioxide (CO2). The relative importance compared CO2 depends on its shorter atmospheric lifetime, stronger warming potential, variations growth rate over past decade, causes which are still debated. Two...
Abstract. The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due a shorter atmospheric lifetime and stronger warming potential than carbon dioxide, challenged by the still unexplained changes of CH4 over past decade. Emissions concentrations are continuing increase, making second most human-induced greenhouse gas after dioxide. Two major difficulties in reducing uncertainties come from...
Abstract The processes controlling advance and retreat of outlet glaciers in fjords draining the Greenland Ice Sheet remain poorly known, undermining assessments their dynamics associated sea-level rise a warming climate. Mass loss has increased six-fold over last four decades, with discharge melt from comprising key components this loss. Here we acquired oceanographic data multibeam bathymetry previously uncharted Sherard Osborn Fjord northwest where Ryder Glacier drains into Arctic Ocean....
Methane (CH4) strongly contributes to observed global warming. As natural CH4 emissions mainly originate from wet ecosystems, it is important unravel how climate change may affect these emissions. This especially true for ebullition (bubble flux sediments), a pathway that has long been underestimated but generally dominates Here we show remarkably strong relationship between and temperature across wide range of freshwater ecosystems on different continents using multi-seasonal data the...
Abstract Methane emissions from lakes are widely thought to be highly irregular and difficult quantify with anything other than numerous distributed measurement stations long‐term sampling campaigns. In spite of this, a large majority the study sites north 50°N have been measured over surprisingly short time periods only one few days. Using data three intensively studied small subarctic lakes, we recommend that measurements diffusive methane flux ebullition should made at least 11 39 days...
Abstract. Following the recent Global Carbon Project (GCP) synthesis of decadal methane (CH4) budget over 2000–2012 (Saunois et al., 2016), we analyse here same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP integrates results from top-down studies (exploiting atmospheric observations within an inverse-modelling framework) bottom-up models (including process-based for estimating land surface emissions chemistry), inventories anthropogenic...
Abstract Emission of methane (CH 4 ) from surface waters is often dominated by ebullition (bubbling), a transport mode with high‐spatiotemporal variability. Based on new and extensive CH data, we demonstrate striking correlations ( r 2 between 0.92 0.997) when comparing seasonal bubble flux three shallow subarctic lakes to four readily measurable proxies incoming energy daily magnitudes sediment temperature 0.86 0.94). Our results after continuous multiyear sampling suggest that predictable...
Abstract The Laptev and East Siberian Seas have been proposed as a substantial source of methane (CH 4 ) to the atmosphere. During summer 2014, we made unique high‐resolution simultaneous measurements CH in atmosphere above, surface waters of, Seas. Turbulence‐driven sea‐air fluxes along ship's track were derived from these observations; an average diffusive flux 2.99 mg m −2 d −1 was calculated for Sea ice‐free portions western Sea, 3.80 . Although seafloor bubble plumes observed at two...
Direct measurements of methane fluxes from the Laptev, East Siberian, and Chukchi seas confirm low regional emissions.
On 28 February 2000, a volcanic cloud from Hekla volcano, Iceland, was serendipitously sampled by DC‐8 research aircraft during the SAGE III Ozone Loss and Validation Experiment (SOLVE I). It encountered at night 10.4 km above sea level (in lower stratosphere) 33–34 hours after emission. The is readily identified abundant SO 2 (≤1 ppmv), HCl (≤70 ppbv), HF (≤60 particles (which may have included fine silicate ash). We compare observed modeled compositions to understand its chemical...
Abstract Quantification of the present and future contribution to atmospheric methane (CH 4 ) from lakes, wetlands, fluvial systems, and, potentially, coastal waters remains an important unfinished task for balancing global CH budget. Discriminating between these sources is crucial, especially across climate‐sensitive Arctic subarctic landscapes waters. Yet basic underlying uncertainties remain, in such areas as total wetland area definitions which can lead conflation wetlands small ponds...
Abstract Northern lakes are important sources of the climate forcing trace gases methane (CH 4 ) and carbon dioxide (CO 2 ). A substantial portion lakes' annual emissions can take place immediately after ice melt in spring. The drivers these fluxes neither well constrained nor fully understood. We present a detailed gas budget for three subarctic lakes, using 6 years eddy covariance 9 manual flux measurements. combine measurements temperature, dissolved oxygen, CH stable isotopologues to...
Abstract The Arctic Ocean is an important sink for atmospheric CO 2 . impact of decreasing sea ice extent and expanding marginal zones on air‐sea exchange depends the rate gas transfer in presence ice. Sea acts to limit by reducing contact between air water but also hypothesized enhance rates across surrounding open‐water surfaces through physical processes such as increased surface‐ocean turbulence from ice‐water shear ice‐edge form drag. Here we present first direct determination velocity...
Abstract The continental shelves of the Arctic Ocean and surrounding seas contain large stocks organic matter (OM) methane (CH 4 ), representing a potential ecosystem feedback to climate change not included in international agreements. We performed structured expert assessment with 25 permafrost researchers combine quantitative estimates sensitivity carbon subsea domain (i.e. unglaciated portions exposed during last glacial period). Experts estimated that contains ∼560 gigatons (GtC;...
Abstract. Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions concentrations of CH4 are continuing increase, making second most human-influenced greenhouse gas in terms forcing, after carbon dioxide (CO2). Assessing relative importance comparison CO2 complicated by its shorter atmospheric lifetime, stronger warming potential, growth rate variations over past decade, causes which still...
Abstract. Lakes and reservoirs contribute to regional carbon budgets via significant emissions of climate forcing trace gases. Here, for improved modelling, we use 8 years floating chamber measurements from three small, shallow subarctic lakes (2010–2017, n=1306) separate the contribution physical biogeochemical processes turbulence-driven, diffusion-limited flux methane (CH4) on daily multi-year timescales. Correlative data include surface water concentration (2009–2017, n=606), total...
Aircraft measurements in the Hekla, Iceland volcanic plume February 2000 revealed large quantities of hydrogen halides within stratosphere correlated to SO 2 . Investigation longer‐term stratospheric impact these emissions, using 3D chemical transport model, SLIMCAT suggests that enhancements H O and HNO 3 increased ·3H particle availability plume. These particles activated HCl HBr, enhancing model concentrations ClO x (20 ppb) BrO (50 ppt). Model decreased near‐zero places, average remained...
Abstract Strong correlations between seasonal energy input and methane (CH 4 ) bubbling (ebullition) in northern lakes suggest that proxies might provide a constraint on the magnitude of future CH emissions. Ebullition is major pathway for transporting anaerobically produced from lake sediments to atmosphere represents large unquantified source. In high‐latitude, postglacial during ice‐free season, solar shortwave can constrain productivity via control sediment temperature. Utilizing...
Abstract. Characterizing methane sources in the Arctic remains challenging due to remoteness, heterogeneity and variety of such emissions. In situ campaigns provide valuable datasets reduce these uncertainties. Here we analyse data from summer 2014 SWERUS-C3 campaign eastern Ocean, off shore Siberia Alaska. Total concentrations methane, as well relative 12CH4 13CH4, were measured continuously during this for 35 d July August. Using a chemistry-transport model, link observed isotopic ratios...
Abstract. In the current era of rapid climate change, accurate characterization climate-relevant gas dynamics – namely production, consumption, and net emissions is required for all biomes, especially those ecosystems most susceptible to impact change. Marine environments include regions that act as sources or sinks numerous climate-active trace gases including methane (CH4) nitrous oxide (N2O). The temporal spatial distributions CH4 N2O are controlled by interaction complex biogeochemical...
Abstract. The central Arctic Ocean (CAO) plays an important role in the global carbon cycle, but current and future exchange of climate-forcing trace gases methane (CH4) dioxide (CO2) between CAO atmosphere is highly uncertain. In particular, there are very few observations near-surface gas concentrations or direct air–sea CO2 flux estimates no previously reported CH4 from CAO. Furthermore, effect sea ice on not well understood. We present measurements CO2, as air–snow fluxes summertime...
Climate change is an existential threat to the vast global permafrost domain. The diverse human cultures, ecological communities, and biogeochemical cycles of this tenth planet depend on persistence frozen conditions. complexity, immensity, remoteness ecosystems make it difficult grasp how quickly things are changing what can be done. Here, we summarize terrestrial marine changes in domain with eye toward policy. While many questions remain, know that continued greenhouse gas emissions...
Abstract. Understanding the recent evolution of methane emissions in Arctic is necessary to interpret global cycle. Emissions are affected by significant uncertainties and sensitive climate change, leading potential feedbacks. A polar version CHIMERE chemistry-transport model used simulate tropospheric during 2012, including all known regional anthropogenic natural sources, particular freshwater which often overlooked modelling. simulations compared atmospheric continuous observations at six...