English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. Atmosphericmarine aerosol particles impact Earth's albedo and climate. These particlescan be primary or secondary and come from a variety of sources, including seasalt, dissolved organic matter, volatile organic compounds, andsulfur-containing compounds. Dimethylsulfide (DMS) marine emissionscontribute greatly to the global biogenic sulfur budget, and its oxidationproducts can contribute to aerosol mass, specifically as sulfuric acid andmethanesulfonic acid (MSA). Further, sulfuric acid is a known nucleatingcompound, and MSA may be able to participate in nucleation when bases areavailable. As DMS emissions, and thus MSA and sulfuric acid from DMSoxidation, may have changed since pre-industrial times and may change in awarming climate, it is important to characterize and constrain the climateimpacts of both species. Currently, global models that simulate aerosol sizedistributions include contributions of sulfate and sulfuric acid from DMSoxidation, but to our knowledge, global models typically neglect the impactof MSA on size distributions. In this study, we use the GEOS-Chem-TOMAS (GC-TOMAS) global aerosolmicrophysics model to determine the impact on aerosol size distributions andsubsequent aerosol radiative effects from including MSA in the size-resolvedportion of the model. The effective equilibrium vapor pressure of MSA iscurrently uncertain, and we use the Extended Aerosol Inorganics Model (E-AIM)to build a parameterization for GC-TOMAS of MSA's effective volatility as afunction of temperature, relative humidity, and available gas-phase bases,allowing MSA to condense as an ideally nonvolatile or semivolatile species ortoo volatile to condense. We also present two limiting cases for MSA'svolatility, assuming that MSA is always ideally nonvolatile (irreversiblecondensation) or that MSA is always ideally semivolatile (quasi-equilibriumcondensation but still irreversible condensation). We further presentsimulations in which MSA participates in binary and ternary nucleation withthe same efficacy as sulfuric acid whenever MSA is treated as ideallynonvolatile. When using the volatility parameterization described above (bothwith and without nucleation), including MSA in the model changes the globalannual averages at 900 hPa of submicron aerosol mass by 1.2 %, N3(number concentration of particles greater than 3 nm in diameter) by −3.9  % (non-nucleating) or 112.5 % (nucleating), N80 by 0.8 %(non-nucleating) or 2.1 % (nucleating), the cloud-albedo aerosol indirecteffect (AIE) by −8.6  mW m −2 (non-nucleating) or −26  mW m −2 (nucleating), and the direct radiative effect (DRE) by −15  mW m −2 (non-nucleating) or −14  mW m −2 (nucleating). The sulfate andsulfuric acid from DMS oxidation produces 4–6 times more submicron mass thanMSA does, leading to an ∼10 times stronger cooling effect in the DRE.But the changes in N80 are comparable between the contributions from MSA andfrom DMS-derived sulfate/sulfuric acid, leading to comparable changes in thecloud-albedo AIE. Model–measurement comparisons with the Heintzenberg et al. (2000) datasetover the Southern Ocean indicate that the default model has a missing sourceor sources of ultrafine particles: the cases in which MSA participates innucleation (thus increasing ultrafine number) most closely match theHeintzenberg distributions, but we cannot conclude nucleation from MSA is thecorrect reason for improvement. Model–measurement comparisons withparticle-phase MSA observed with a customized Aerodyne high-resolutiontime-of-flight aerosol mass spectrometer (AMS) from the ATom campaign showthat cases with the MSA volatility parameterizations (both with and withoutnucleation) tend to fit the measurements the best (as this is the first useof MSA measurements from ATom, we provide a detailed description of thesemeasurements and their calibration). However, no one model sensitivity caseshows the best model–measurement agreement for both Heintzenberg and theATom campaigns. As there are uncertainties in both MSA's behavior (nucleationand condensation) and the DMS emissions inventory, further studies on bothfronts are needed to better constrain MSA's past, current, and future impactsupon the global aerosol size distribution and radiative forcing.

The potential role of methanesulfonic acid (MSA) in aerosol formation and growth and the associated radiative forcings