Physical Sciences and Mathematics Commons^™

Production Mechanisms, Number Concentration, Size Distribution, Chemical Composition, And Optical Properties Of Sea Spray Aerosols, Nicholas Meskhidze, Markus D. Petters, Kostas Tsigaridis, Tim Bates, Colin O'Dowd, Jeff Reid, Ernie R. Lewis, Brett Gantt, Magdalena D. Anguelova, Prakash V. Bhave, Andrew Wozniak

Chemistry & Biochemistry Faculty Publications

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The impact of sea spray aerosols on global climate remains one of the most uncertain components of the aerosol–radiation–climate problem, but has received less attention than the impacts of terrestrial and anthropogenic aerosols. The last decade has produced a large body of information regarding the sources and composition of marine aerosols, resulting in a reassessment of the complex role that sea spray particles play in climate and various geophysical phenomena. As sea spray aerosol contributes substantially to the preindustrial, natural background which provides the baseline on top of which anthropogenic forcing should be quantified, and because the ocean …

Quantifying The Impact Of Boreal Forest Fires On Tropospheric Oxidants Over The Atlantic Using Aircraft And Satellites (Bortas) Experiment: Design, Execution And Science Overview, P. I. Palmer, M. Parrington, J. D. Lee, A, C. Lewis, A. R. Rickard, P. F. Bernath, T. J. Duck, D. L. Waugh, D. W. Tarasick, S. Andrews

Chemistry & Biochemistry Faculty Publications

We describe the design and execution of the BORTAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) experiment, which has the overarching objective of understanding the chemical aging of air masses that contain the emission products from seasonal boreal wildfires and how these air masses subsequently impact downwind atmospheric composition. The central focus of the experiment was a two-week deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA) over eastern Canada, based out of Halifax, Nova Scotia. Atmospheric ground-based and sonde measurements over Canada and the Azores associated with the planned …

Ace-Fts Observations Of Pyrogenic Trace Species In Boreal Biomass Burning Plumes During Bortas, K. A. Tereszchuk, G. G. Abad, C. Clerbaux, J. Hadji-Lazaro, D. Hurtmans, P. F. Coheur, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

To further our understanding of the effects of biomass burning emissions on atmospheric composition, the BORTAS campaign (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) was conducted on 12 July to 3 August 2011 during the boreal forest fire season in Canada. The simultaneous aerial, ground and satellite measurement campaign sought to record instances of boreal biomass burning to measure the tropospheric volume mixing ratios (VMRs) of short- and long-lived trace molecular species from biomass burning emissions. The goal was to investigate the connection between the composition and the distribution of these pyrogenic outflows and …

Ace-Fts Observations Of Acetonitrile In The Lower Stratosphere, J. J. Harrison, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

This work reports the first infrared satellite remote-sensing measurements of acetonitrile (CH₃CN) in the Earth's atmosphere using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) between 2004 and 2011. The retrieval scheme uses new quantitative laboratory spectroscopic measurements of acetonitrile (Harrison and Bernath, 2012). Although individual ACE-FTS profile measurements are dominated by measurement noise, median profiles in 10 degrees latitude bins show a steady decline in volume mixing ratio from similar to 150 ppt (parts per trillion) at 11.5 km to < 40 ppt at 25.5-29.5 km. These new measurements agree well with the scant available air-and balloon-borne data in the lower stratosphere. An acetonitrile stratospheric lifetime of 73 ± 20 yr has been determined.

Hci And Cio Profiles Inside The Antarctic Vortex As Observed By Smiles In November 2009: Comparisons With Mls And Ace-Fts Instruments, T. Sugita, Y. Kasai, Y. Terao, S. Hayashida, G. L. Manney, W. H. Daffer, H. Sagawa, M. Suzuki, M. Shiotani, K. A. Walker, C. D. Boone, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

We present vertical profiles of hydrogen chloride (HCl) and chlorine monoxide (ClO) as observed by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station (ISS) inside the Antarctic vortex on 19-24 November 2009. The SMILES HCl value reveals 2.8-3.1 ppbv between 450K and 500K levels in potential temperature (PT). The high value of HCl is highlighted since it is suggested that HCl is a main component of the total inorganic chlorine Cl_y, defined as Cl_y similar or equal to HCl + ClO + chlorine nitrate ClONO₂, inside the Antarctic vortex in spring, owing …

Uncertainties In Modelling Heterogeneous Chemistry And Arctic Ozone Depletion In The Winter 2009/2010, I. Wohltmann, T. Wegner, R. Müller, R. Lehmann, M. Rex, G. L. Manney, M. L. Santee, P. Bernath, O. Suminska-Ebersoldt

Chemistry & Biochemistry Faculty Publications

Stratospheric chemistry and denitrification are simulated for the Arctic winter 2009/2010 with the Lagrangian Chemistry and Transport Model ATLAS. A number of sensitivity runs is used to explore the impact of uncertainties in chlorine activation and denitrification on the model results. In particular, the efficiency of chlorine activation on different types of liquid aerosol versus activation on nitric acid trihydrate clouds is examined. Additionally, the impact of changes in reaction rate coefficients, in the particle number density of polar stratospheric clouds, in supersaturation, temperature or the extent of denitrification is investigated. Results are compared to satellite measurements of MLS and …

Validation Of Stratospheric And Mesospheric Ozone Observed By Smiles From International Space Station, Y. Kasai, H. Sagawa, D. Kreyling, E. Dupuy, P. Baron, J. Mendrok, K Suzuki, T. O. Sato, T. Nishibori, S. Mizobuchi, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

We observed ozone O₃ in the vertical region between 250 and 0.0005 hPa (~ 12-96 km) using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the Japanese Experiment Module (JEM) of the International Space Station (ISS) between 12 October 2009 and 21 April 2010. The new 4K superconducting heterodyne receiver technology of SMILES allowed us to obtain a one order of magnitude better signal-to-noise ratio for the O₃ line observation compared to past spaceborne microwave instruments. The non-sun-synchronous orbit of the ISS allowed us to observe O₃ at various local times. We assessed the quality of the vertical …

Hydrocarbons In The Upper Troposphere And Lower Stratosphere Observed From Ace-Fts And Comparisons With Waccm, Mijeong Park, William J. Randel, Douglas E. Kinnison, Louisa K. Emmons, Peter F. Bernath, Kaley A. Walker, Chris D. Boone, Nathaniel J. Livesey

Chemistry & Biochemistry Faculty Publications

Satellite measurements from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) are used to examine the global, seasonal variations of several hydrocarbons, including carbon monoxide (CO), ethane (C₂H₆), acetylene (C₂H₂), and hydrogen cyanide (HCN). We focus on quantifying large-scale seasonal behavior from the middle troposphere to the stratosphere, particularly in the tropics, and furthermore make detailed comparisons with the Whole Atmosphere Community Climate Model (WACCM) chemistry climate model (incorporating tropospheric photochemistry, time-varying hydrocarbon emissions, and meteorological fields nudged from reanalysis). Comparisons with Microwave Limb Sounder (MLS) measurements of CO are also included …

A Preliminary Examination Of An In Situ Dual Dye Approach To Measuring Light Fluxes In Lotic Systems, Elizabeth C. Minor, Elizabeth James, Jay A. Austin, Veronica Nelson, Ryan Lusk, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

Light is a critical parameter in aquatic ecosystems, affecting primary production and in situ photochemistry. However, measuring light exposure for suspended particles or dissolved components in a dynamic water column can be challenging with existing Eulerian approaches. Here, we assess the simultaneous deployment of two dyes differing in photolability (rhodamine WT and fluorescein) as a Lagrangian measure of sunlight exposure in a lotic system. Fluorescein is sensitive to light exposure; rhodamine WT is relatively photostable. We examined dye fluorescence at various pH, salinity, and temperature conditions. We also tested dye photolability as a function of pH and wavelength range. In …

The Relation Between Atmospheric Humidity And Temperature Trends For Stratospheric Water, S. Fueglistaler, Y. S. Liu, T. J. Flannaghan, P. H. Haynes, D. P. Dee, W. J. Read, E. E. Remsberg, L. W. Thomason, D. F. Hurst, J. R. Lanzante, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

We analyze the relation between atmospheric temperature and water vapor-a fundamental component of the global climate system-for stratospheric water vapor (SWV). We compare measurements of SWV (and methane where available) over the period 1980-2011 from NOAA balloon-borne frostpoint hygrometer (NOAA-FPH), SAGE II, Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS)/Aura, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) to model predictions based on troposphere-to-stratosphere transport from ERA-Interim, and temperatures from ERA-Interim, Modern Era Retrospective- Analysis (MERRA), Climate Forecast System Reanalysis (CFSR), Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC), HadAT2, and RICHv1.5. All model predictions are dry biased. The interannual …

Improved Method For Quantifying The Air-Sea Flux Of Volatile And Semi-Volatile Organic Carbon, Emily Hauser, Rebecca M. Dickhut, Renee Falconer, Andrew S. Wozniak

Chemistry & Biochemistry Faculty Publications

A method for quantifying the diffusive air-sea exchange of gaseous organic carbon (OC) was developed. OC compounds were separated into two operational pools-those that were kinetically air limited in diffusion across the air-sea interface and those that were water limited-during simultaneous air/water sampling. The method separates OC compounds into low Henry's law constant (low-H) semivolatile OC (SOC) and high Henry's law constant (high-H) volatile OC (VOC) pools that can be categorized by relating diffusion kinetic parameters to Henry's Law constant. Air limited (low-H; H << similar to 0.1 L atm mol(^-1)) compounds were collected in pure water traps and were quantified as dissolved OC, whereas …

Observations Of Peroxyacetyl Nitrate (Pan) In The Upper Troposphere By The Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (Ace-Fts), K. A. Tereszchuk, D. P. Moore, J. J. Harrison, C. D. Boone, M. Park, J. J. Remedios, W. J. Randel, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Peroxyacetyl nitrate (CH₃CO·O₂NO₂, abbreviated as PAN) is a trace molecular species present in the troposphere and lower stratosphere due primarily to pollution from fuel combustion and the pyrogenic outflows from biomass burning. In the lower troposphere, PAN has a relatively short lifetime and is principally destroyed within a few hours through thermolysis, but it can act as a reservoir and carrier of NO_x in the colder temperatures of the upper troposphere, where UV photolysis becomes the dominant loss mechanism. Pyroconvective updrafts from large biomass burning events can inject PAN into the upper troposphere …

Stratospheric Lifetimes Of Cfc-12, Ccl4, Ch4, Ch3cl And N20 From Measurements Made By The Atmospheric Chemistry Experiment-Fourier Transform Spectrometer, A. T. Brown, C. M. Volk, M. R. Schoebert, C. D. Boone, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Long lived halogen-containing compounds are important atmospheric constituents since they can act both as a source of chlorine radicals, which go on to catalyse ozone loss, and as powerful greenhouse gases. The long-term impact of these species on the ozone layer is dependent on their stratospheric lifetimes. Using observations from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) we present calculations of the stratospheric lifetimes of CFC-12, CCl₄, CH₄, CH₃Cl and N₂O. The lifetimes were calculated using the slope of the tracer-tracer correlation of these species with CFC-11 at the tropopause. The …

Stratospheric Loss And Atmospheric Lifetimes Of Cfc-11 And Cfc-12 Derived From Satellite Observations, K. Minschwaner, L. Hoffmann, A. Brown, M. Riese, R. Müller, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

The lifetimes of CFC-11 and CFC-12 have been evaluated using global observations of their stratospheric distributions from satellite-based instruments over the time period from 1992 to 2010. The chlorofluorocarbon (CFC) datasets are from the Cryogen Limb Array Etalon Spectrometer (CLAES), the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA-1 and CRISTA-2), the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), and the Atmospheric Chemistry Experiment (ACE). Stratospheric loss rates were calculated using an ultraviolet radiative transfer code with updated cross section and solar irradiance data. Mean steady-state lifetimes based on these observations are 44.7 (36-58) yr for CFC-11 and 106.6 …

Harmonized Dataset Of Ozone Profiles From Satellite Limb And Occultation Measurements, V. F. Sofieva, N. Rahpoe, J. Tamminen, E. Kyrölä, N. Kalakoski, M. Weber, A. Rozanov, C. Von Savigny, A Laeng, T. Von Clarmann, P. Bernath, R. J. Hargreaves

Chemistry & Biochemistry Faculty Publications

In this paper, we present a HARMonized dataset of OZone profiles (HARMOZ) based on limb and occultation measurements from Envisat (GOMOS, MIPAS and SCIAMACHY), Odin (OSIRIS, SMR) and SCISAT (ACE-FTS) satellite instruments. These measurements provide high-vertical-resolution ozone profiles covering the altitude range from the upper troposphere up to the mesosphere in years 2001-2012. HARMOZ has been created in the framework of the European Space Agency Climate Change Initiative project. The harmonized dataset consists of original retrieved ozone profiles from each instrument, which are screened for invalid data by the instrument teams. While the original ozone profiles are presented in different …