A5037222986- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Planetary Science and Exploration
- Atmospheric and Environmental Gas Dynamics
- Solar and Space Plasma Dynamics
- Spectroscopy and Laser Applications
- Atmospheric aerosols and clouds
- Astrophysics and Star Formation Studies
- Geomagnetism and Paleomagnetism Studies
- Advanced Chemical Physics Studies
- Space Exploration and Technology
- Stellar, planetary, and galactic studies
- Air Quality Monitoring and Forecasting
- Laser-induced spectroscopy and plasma
- Geology and Paleoclimatology Research
- Marine and coastal ecosystems
- Air Quality and Health Impacts
- Radioactive contamination and transfer
- Earthquake Detection and Analysis
- Methane Hydrates and Related Phenomena
- Catalytic Processes in Materials Science
- Mercury impact and mitigation studies
- Space exploration and regulation
University of Leeds
2016-2025
University of Manchester
2000-2021
Florence (Netherlands)
2019
National Centre for Atmospheric Science
2010-2018
Charles River Laboratories (Netherlands)
2016
University of East Anglia
2000-2011
Consejo Superior de Investigaciones Científicas
2011
University of York
2011
Universidade de Santiago de Compostela
2010
University of Nottingham
2005-2009
Abstract. During springtime in the polar regions, unique photochemistry converts inert halide salt ions (e.g. Br−) into reactive halogen species Br atoms and BrO) that deplete ozone boundary layer to near zero levels. Since their discovery late 1980s, research on depletion events (ODEs) has made great advances; however many key processes remain poorly understood. In this article we review history, chemistry, dependence environmental conditions, impacts of ODEs. This shown central role...
Abstract. It has been shown that sunlit snow and ice plays an important role in processing atmospheric species. Photochemical production of a variety chemicals recently reported to occur snow/ice the release these photochemically generated species may significantly impact chemistry overlying atmosphere. Nitrogen oxide oxidant precursor fluxes have measured number covered environments, where some cases emissions boundary layer. For example, photochemical ozone (such as occurring polluted...
Interest in stratospheric aerosol and its role climate have increased over the last decade due to observed increase since 2000 potential for changes sulfur cycle induced by change. This review provides an overview about advances research comprehensive assessment of was published 2006. A crucial development 2006 is substantial improvement agreement between situ space-based inferences properties during volcanically quiescent periods. Furthermore, new measurement systems techniques, both space...
Halogens influence the oxidizing capacity of Earth's troposphere, and iodine oxides form ultrafine aerosols, which may have an impact on climate. We report year-round measurements boundary layer oxide bromine at near-coastal site Halley Station, Antarctica. Surprisingly, both species are present throughout sunlit period exhibit similar seasonal cycles concentrations. The springtime peak (20 parts per trillion) is highest concentration recorded anywhere in atmosphere. These levels halogens...
We model the synthesis of molecules and dust in inner wind oxygen-rich Mira-type star IK Tau, by considering effects periodic shocks induced stellar pulsation on gas, following non-equilibrium chemistry shocked gas layers between 1 10 Rstar. consider a complete set clusters, combine nucleation phase formation with condensation these clusters into grains. Our derived molecular abundances properties are compared to most recent observational data. The is described using chemical kinetic network...
Abstract Observational evidence shows the ubiquitous presence of ocean-emitted short-lived halogens in global atmosphere 1–3 . Natural emissions these chemical compounds have been anthropogenically amplified since pre-industrial times 4–6 , while, addition, anthropogenic halocarbons are currently being emitted to 7,8 Despite their widespread distribution atmosphere, combined impact species on Earth’s radiative balance remains unknown. Here we show that exert a substantial indirect cooling...
Large increases in the number of low earth orbit satellites are projected coming decades [L. Schulz, K.-H. Glassmeier, Adv. Space Res.67, 1002-1025 (2021)] with perhaps 50,000 additional by 2030 [GAO, constellations satellites: Mitigating environmental and other effects (2022)]. When spent rocket bodies defunct reenter atmosphere, they produce metal vapors that condense into aerosol particles descend stratosphere. So far, models spacecraft reentry have focused on understanding hazard...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical formation of hydrogen peroxide in natural waters exposed to sunlightWilliam J. Cooper, Rod G. Zika, Robert Petasne, and John M. C. PlaneCite this: Environ. Sci. Technol. 1988, 22, 10, 1156–1160Publication Date (Print):October 1, 1988Publication History Published online1 May 2002Published inissue 1 October 1988https://pubs.acs.org/doi/10.1021/es00175a004https://doi.org/10.1021/es00175a004research-articleACS PublicationsRequest reuse...
The oxidation of elemental mercury (Hg0) to the divalent gaseous dibromide (HgBr2) has been proposed account for removal Hg0 during depletion events in springtime Arctic. mechanism this process is explored paper by theoretical calculations relevant rate coefficients. Rice−Ramsberger−Kassel−Marcus (RRKM) theory, together with ab initio quantum where required, are used estimate following: recombination coefficients Hg Br, I, and O; thermal dissociation coefficient HgBr; HgBr OH, O2. A based on...
An observationally constrained photochemical box model has been developed to investigate the atmospheric chemistry of iodine in marine boundary layer, motivated by recent measurements monoxide (IO) radical (Allan et al., this issue). Good agreement with time series IO measured at a midlatitude coastal station was achieved using reaction scheme that included recycling through aerosol. The strong diurnal variation observed subtropical Atlantic satisfactorily modeled assuming constant...
Abstract. Renewal of ultrafine aerosols in the marine boundary layer may lead to repopulation distribution and ultimately determine concentration cloud condensation nuclei (CCN). Thus formation nanometre-scale particles can enhanced scattering incoming radiation a net cooling atmosphere. The recent demonstration chamber new from photolytic production condensable iodine-containing compounds diiodomethane (CH2I2), (O'Dowd et al., 2002; Kolb, Jimenez 2003a; Burkholder Ravishankara, 2003),...
The atmospheric chemistry of iodine is important for several reasons, including the influence oxides on oxidising capacity troposphere, formation new particles, and enrichment in marine aerosols transport this essential dietary element to continents. It shown here that a substantial source I 2 , most likely emitted from macro‐algae at low tide. This accounts daytime production particles coastal boundary layer, also explains discovery significant night‐time levels oxides.
Concurrent measurements of ultra‐fine (r<5 nm) particle (UFP) formation, OH and SO 2 concentrations in the coastal environment are examined to further elucidate processes leading tidal‐related homogeneous heteromolecular nucleation. During almost daily nucleation events, UFP concentration approached ≈300,000 cm −3 under conditions solar radiation low tide. Simultaneous illustrate that, as well occurring during tide, these events occur peak concentration, suggesting that at least one...
Abstract. Most of the extraterrestrial dust entering Earth's atmosphere ablates to produce metal vapours, which have significant effects on aeronomy upper mesosphere and lower thermosphere. A new Chemical Ablation Model (CAMOD) is described treats physics chemistry ablation, by including following processes: sputtering inelastic collisions with air molecules before meteoroid melts; evaporation atoms oxides from molten particle; diffusion-controlled migration volatile constituents (Na K)...
Abstract The presence of thin layers free metal atoms at around 90 km in the upper atmosphere has been known for about fifty years. Layers alkali metals Na, K and Li, as well Ca Fe, have observed. This discovery posed two important questions. First, what is source metals: interplanetary or terrestrial? Secondly, nature chemistry that causes reactive such sodium to exist their atomic form atmosphere? first part this review covers techniques developed observe layers, including ground-, rocket-...
Abstract. We have integrated observations of tropospheric ozone, very short-lived (VSL) halocarbons and reactive iodine bromine species from a wide variety tropical data sources with the global CAM-Chem chemistry-climate model offline radiative transfer calculations to compute contribution halogen chemistry ozone loss associated impact in marine troposphere. The inclusion leads an annually averaged depletion around 10% (~2.5 Dobson units) column, largest effects middle upper This contributes...
Abstract. Fluorescence Assay by Gas Expansion (FAGE) has been used to detect ambient levels of OH and HO2 radicals at the Cape Verde Atmospheric Observatory, located in tropical Atlantic marine boundary layer, during May June 2007. Midday radical concentrations were high, with maximum 9 ×106 molecule cm−3 6×108 observed for HO2, respectively. A box model incorporating detailed Master Chemical Mechanism, extended include halogen chemistry, heterogeneous loss processes constrained all...
Abstract. Although tropospheric reactive halogen chemistry is well studied in coastal and polar environments, the presence of halogens over open ocean environment has not been widely reported. The impacts on tropical marine boundary layer (MBL), particular, are characterised. This paper describes observations iodine monoxide (IO) bromine oxide (BrO) eight months MBL, north-eastern side São Vicente (Cape Verde Islands, 16.85° N, 24.87° W). highest BrO mixing ratio observed was 5.6±1 pmol...