An Aitken mode aerosol formation event in the high Arctic: evidence for aggregate breakup

2021 ◽  
Author(s):  
Michael Lawler ◽  
Eric Saltzman ◽  
Linn Karlsson ◽  
Paul Zieger ◽  
Matthew Salter ◽  
...  
Keyword(s):  
Atmospheric Transport ◽  
Methanesulfonic Acid ◽  
High Arctic ◽  
Sea Salt ◽  
Surface Energy Budget ◽  
Cloud Formation ◽  
Aerosol Size Distribution ◽  
Sea Spray ◽  
Aerosol Formation ◽  
Aitken Mode

<p>The summertime high Arctic is an extremely low-aerosol region, where even small inputs of particles can have significant impacts on cloud formation and therefore on the surface energy budget. The relative importance of new particle formation from gas phase precursors and primary sea spray production in this region remains uncertain, as does the role of atmospheric transport. We made direct, time-resolved composition measurements of Aitken mode (~20-60 nm diameter) aerosol over the high Arctic pack ice in August-September 2018, including during an intense Aitken mode formation event on August 30-31. The event particles contained both primary sea spray materials (sodium, potassium, and polysaccharide-like organics) and secondary components (non-sea-salt sulfate, methanesulfonic acid, non-sea-salt iodine, and secondary organics), most of which could be quantified on the basis of analytical standards. The composition is consistent with primary sea spray that had been atmospherically processed, and the aerosol size distribution dynamics imply the action of a process by which larger atmospheric particles or aggregates broke up to form smaller particles. Hypotheses to explain the results will be discussed.</p>

scholarly journals Solute in high arctic glacier snow cover and its impact on runoff chemistry

1998 ◽  
Vol 26 ◽  
pp. 156-160 ◽  
Author(s):  
Richard Hodgkins ◽  
Martyn Tranter
Keyword(s):  
Chemical Composition ◽  
Atmospheric Transport ◽  
Total Concentration ◽  
High Arctic ◽  
Sea Salt ◽  
Acidic Ph ◽  
Sea Salt Aerosol ◽  
Wet Snow ◽  
Potential Contributor ◽  
Arctic Glacier

The chemical composition of snow and meltwater in the 13 km2 catchment of Scott Turnerbreen, Svalbard, was investigated during the spring and summer of 1993. This paper assesses the provenance of solute in the snowpack and its impact on runoff chemistry. Dry snow contains 420μeql-1 of solute, is slightly acidic (pH 5.4) and is dominated by Na+ and Cl-. Wet snow is more dilute (total concentration 340μeql-1), and less acidic (pH 5.9). This is consistent with the elution of ions from the snowpack by meltwater. Snowpack solute can be partitioned into the following fractions: sea-salt aerosol, acid aerosol and crustal. About 98% of snowpack solute is sea salt, yielding 22000 kg km-2a-1. The behaviour of snowpack-derived Cl- in runoff is distinctive, peaking at over 800 μeql-1 early in the melt season as runoff picks up, before declining quasi-exponentially. This represents the discharge of snowmelt concentrated by elution within the snowpack which subsequently becomes relatively dilute. A solute yield of 140 kg km-2 a-1 can be attributed to anthropogenically generated acid aerosols, representing long-range atmospheric transport of pollutants, a potential contributor to Arctic runoff acidification.

scholarly journals New index of organic mass enrichment in sea spray aerosols linked with senescent status in marine phytoplankton

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuzo Miyazaki ◽  
Koji Suzuki ◽  
Eri Tachibana ◽  
Youhei Yamashita ◽  
Astrid Müller ◽  
...  
Keyword(s):  
Marine Phytoplankton ◽  
Cloud Formation ◽  
Sea Spray ◽  
Breakdown Product ◽  
Biological Processes ◽  
Marine Aerosol ◽  
Aerosol Formation ◽  
Organic Mass ◽  
Western Subarctic Pacific ◽  
Highly Correlated

Abstract Linking the amount of organic matter (OM) in sea spray aerosols (SSAs) to biological processes in ocean surface is essential for understanding marine aerosol formation and their potential to affect cloud formation. To date, chlorophyll (Chl) a concentration has been widely used as a surrogate for surface phytoplankton biomass or productivity to predict the relative abundance of OM in SSAs (OMSSA). Here we show a new index to present OMSSA using concentrations of Chl a and chlorophyllide (Chllide) a, which is a breakdown product of Chl a and has been used as a biomarker of senescent algal cells. The index was compared with submicrometer OMSSA, based on surface seawater and aerosol samples obtained during the pre-bloom in the western subarctic Pacific. Our results showed that the OMSSA was highly correlated with this unique index, suggesting that the OMSSA was closely linked with senescent algal cells and/or cell lysis. Furthermore, the hygroscopicity parameters κ derived from water-extracted SSA samples implied a reduction in the SSA hygroscopicity with increasing senescent status of phytoplankton. The index can represent OMSSA on a timescale of a day during the pre-bloom period, which should be further examined over different oceanic regions.

scholarly journals Sub-Antarctic marine aerosol: dominant contributions from biogenic sources

2013 ◽  
Vol 13 (17) ◽  
pp. 8669-8694 ◽  
Author(s):  
J. Schmale ◽  
J. Schneider ◽  
E. Nemitz ◽  
Y. S. Tang ◽  
U. Dragosits ◽  
...  
Keyword(s):  
Methanesulfonic Acid ◽  
Sea Salt ◽  
Submicron Particles ◽  
Sea Spray ◽  
Local Fauna ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Organic Factor ◽  
Sea Spray Aerosol ◽  
Highly Correlated

Abstract. Biogenic influences on the composition and characteristics of aerosol were investigated on Bird Island (54°00' S, 38°03' W) in the South Atlantic during November and December 2010. This remote marine environment is characterised by large seabird and seal colonies. The chemical composition of the submicron particles, measured by an aerosol mass spectrometer (AMS), was 21% non-sea-salt sulfate, 2% nitrate, 8% ammonium, 22% organics and 47% sea salt including sea salt sulfate. A new method to isolate the sea spray signature from the high-resolution AMS data was applied. Generally, the aerosol was found to be less acidic than in other marine environments due to the high availability of ammonia, from local fauna emissions. By positive matrix factorisation five different organic aerosol (OA) profiles could be isolated: an amino acid/amine factor (AA-OA, 18% of OA mass), a methanesulfonic acid OA factor (MSA-OA, 25%), a marine oxygenated OA factor (M-OOA, 41%), a sea spray OA fraction (SS-OA, 7%) and locally produced hydrocarbon-like OA (HOA, 9%). The AA-OA was dominant during the first two weeks of November and found to be related with the hatching of penguins in a nearby colony. This factor, rich in nitrogen (N : C ratio = 0.13), has implications for the biogeochemical cycling of nitrogen in the area as particulate matter is often transported over longer distances than gaseous N-rich compounds. The MSA-OA was mainly transported from more southerly latitudes where phytoplankton bloomed. The bloom was identified as one of three sources for particulate sulfate on Bird Island, next to sea salt sulfate and sulfate transported from South America. M-OOA was the dominant organic factor and found to be similar to marine OA observed at Mace Head, Ireland. An additional OA factor highly correlated with sea spray aerosol was identified (SS-OA). However, based on the available data the type of mixture, internal or external, could not be determined. Potassium was not associated with sea salt particles during 19% of the time, indicating the presence of biogenic particles in addition to the MSA-OA and AA-OA factors.

scholarly journals Solute in high arctic glacier snow cover and its impact on runoff chemistry

1998 ◽  
Vol 26 ◽  
pp. 156-160 ◽  
Author(s):  
Richard Hodgkins ◽  
Martyn Tranter
Keyword(s):  
Chemical Composition ◽  
Atmospheric Transport ◽  
Total Concentration ◽  
High Arctic ◽  
Sea Salt ◽  
Acidic Ph ◽  
Sea Salt Aerosol ◽  
Wet Snow ◽  
Potential Contributor ◽  
Arctic Glacier

The chemical composition of snow and meltwater in the 13 km2catchment of Scott Turnerbreen, Svalbard, was investigated during the spring and summer of 1993. This paper assesses the provenance of solute in the snowpack and its impact on runoff chemistry. Dry snow contains 420μeql-1of solute, is slightly acidic (pH 5.4) and is dominated by Na+and Cl-. Wet snow is more dilute (total concentration 340μeql-1), and less acidic (pH 5.9). This is consistent with the elution of ions from the snowpack by meltwater. Snowpack solute can be partitioned into the following fractions: sea-salt aerosol, acid aerosol and crustal. About 98% of snowpack solute is sea salt, yielding 22000 kg km-2a-1. The behaviour of snowpack-derived Cl-in runoff is distinctive, peaking at over 800 μeql-1early in the melt season as runoff picks up, before declining quasi-exponentially. This represents the discharge of snowmelt concentrated by elution within the snowpack which subsequently becomes relatively dilute. A solute yield of 140 kg km-2a-1can be attributed to anthropogenically generated acid aerosols, representing long-range atmospheric transport of pollutants, a potential contributor to Arctic runoff acidification.

scholarly journals Cloud condensation nuclei over the Southern Ocean: wind dependence and seasonal cycles

2017 ◽  
Vol 17 (7) ◽  
pp. 4419-4432 ◽  
Author(s):  
John L. Gras ◽  
Melita Keywood
Keyword(s):  
Wind Speed ◽  
Southern Ocean ◽  
Marine Boundary Layer ◽  
Numerical Models ◽  
Cloud Condensation Nuclei ◽  
Sea Salt ◽  
Aerosol Size Distribution ◽  
Condensation Nuclei ◽  
Coarse Mode ◽  
Aitken Mode

Abstract. Multi-decadal observations of aerosol microphysical properties from regionally representative sites can be used to challenge regional or global numerical models that simulate atmospheric aerosol. Presented here is an analysis of multi-decadal observations at Cape Grim (Australia) that characterise production and removal of the background marine aerosol in the Southern Ocean marine boundary layer (MBL) on both short-term weather-related and underlying seasonal scales.A trimodal aerosol distribution comprises Aitken nuclei (< 100 nm), cloud condensation nuclei (CCN)/accumulation (100–350 nm) and coarse-particle (> 350 nm) modes, with the Aitken mode dominating number concentration. Whilst the integrated particle number in the MBL over the clean Southern Ocean is only weakly dependent on wind speed, the different modes in the aerosol size distribution vary in their relationship with wind speed. The balance between a positive wind dependence in the coarse mode and negative dependence in the accumulation/CCN mode leads to a relatively flat wind dependence in summer and moderately strong positive wind dependence in winter. The changeover in wind dependence of these two modes occurs in a very small size range at the mode intersection, indicative of differences in the balance of production and removal in the coarse and accumulation/CCN modes.Whilst a marine biological source of reduced sulfur appears to dominate CCN concentration over the summer months (December to February), other components contribute to CCN over the full annual cycle. Wind-generated coarse-mode sea salt is an important CCN component year round and is the second-most-important contributor to CCN from autumn through to mid-spring (March to November). A portion of the non-seasonally dependent contributor to CCN can clearly be attributed to wind-generated sea salt, with the remaining part potentially being attributed to long-range-transported material. Under conditions of greater supersaturation, as expected in more convective cyclonic systems and their associated fronts, Aitken mode particles become increasingly important as CCN.

scholarly journals Measurements of Atmospheric Variability during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Expedition

2021 ◽  
Author(s):  
Julia Schmale ◽  
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
High Arctic ◽  
Physical Structure ◽  
Surface Energy Budget ◽  
Arctic Climate ◽  
Cloud Formation ◽  
The Arctic ◽  
Atmospheric Variability ◽  
Atmospheric Measurements

&lt;p&gt;The MOSAiC expedition was designed to better understand the local and remote processes influencing the Arctic climate system. The Arctic is warming two to three times faster than the global average, a process known as Arctic amplification. One of the most significant consequences is the retreat of sea ice, which has already diminished by roughly 40 % since satellite measurements began. The Arctic atmospheric, marine and terrestrial changes have important effects on local processes, such as moisture sources, cloud formation, radiative and energy transfer, amongst other. They also have the potential to induce changes to large-scale circulation, which can impact the mid-latitudes of Eurasia and North America. &amp;#160;&amp;#160;&amp;#160;&lt;/p&gt;&lt;p&gt;Between September 2019 and October 2020 the MOSAiC expedition performed a large number of atmospheric measurements in the high Arctic, drifting most of the time with the sea ice. Instrumentation was operated from the icebreaker Polarstern (Alfred Wegener Institute), on the sea ice and on flying platforms. Observations covered generally: (i) the atmospheric physical structure (e.g., temperature, humidity, wind speed and direction profiles) with radio soundings, ground-based remote sensing, as well as towers; (ii) clouds and precipitation with a host of lidars, radars and radiometers, as well as distrometers and specific hydrometeor observations; (iii) aerosols and trace gases with real-time measurements as well as offline techniques for chemical and microphysical properties; and (iv) the surface energy budget with measurements of radiation, turbulent fluxes and conductive fluxes. &amp;#160;&lt;/p&gt;&lt;p&gt;The year-round measurements allow for the study of atmospheric variability during the annual cycle with the important processes of sea ice freeze-up and melting. Other event-based features, such as warm air mass intrusions, cyclones, storms, and lead opening, were studied in detail to understand the implications of these processes for the Arctic system. MOSAiC observations are in addition contributing to the evaluation of satellite-based observations such as radiation fluxes or cloud properties, as well as to the evaluation and improvement of numerical simulations, ranging from simpler box to complex Earth System Models. &amp;#160;&lt;/p&gt;&lt;p&gt;This presentation will provide an overview of the first atmospheric observational results during MOSAiC.&lt;/p&gt;

scholarly journals Exploring DMS oxidation and implications for global aerosol radiative forcing

2021 ◽  
Author(s):  
Ka Ming Fung ◽  
Colette L. Heald ◽  
Jesse H. Kroll ◽  
Siyuan Wang ◽  
Duseong S. Jo ◽  
...  
Keyword(s):  
Gas Phase ◽  
Radiative Forcing ◽  
Dimethyl Sulfide ◽  
Methanesulfonic Acid ◽  
Atmospheric Model ◽  
Cloud Formation ◽  
Aerosol Formation ◽  
Gas Phase Chemistry ◽  
Dms Oxidation ◽  
Phase Chemistry

Abstract. Aerosol indirect radiative forcing (IRF), which characterizes how aerosols alter cloud formation and properties, is very sensitive to the preindustrial (PI) aerosol burden. Dimethyl sulfide (DMS), emitted from the ocean, is a dominant natural precursor of non-sea-salt sulfate in the PI and pristine present-day (PD) atmospheres. Here we revisit the atmospheric oxidation chemistry of DMS, particularly under pristine conditions, and its impact on aerosol IRF. Based on previous laboratory studies, we expand the simplified DMS oxidation scheme used in the Community Atmospheric Model version 6 with chemistry (CAM6-chem) to capture the OH-addition pathway as well as the H-abstraction pathway and the associated isomerization branch. These additional oxidation channels of DMS produce several stable intermediate compounds, e.g., methanesulfonic acid (MSA) and hydroperoxymethyl thioformate (HPMTF), delay the formation of sulfate, and hence, alter the spatial distribution of sulfate aerosol and radiative impacts. The expanded scheme improves the agreement between modeled and observed concentrations of DMS, MSA, HPMTF, and sulfate over most marine regions based on the NASA Atmospheric Tomography (ATom), the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA), and the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) measurements. We find that the global HPMTF burden, as well as the burden of sulfate produced from DMS oxidation are relatively insensitive to the assumed isomerization rate, but the burden of HPMTF is very sensitive to a potential additional cloud loss. We find that global sulfate burden under PI and PD emissions increase to 412 Gg-S (+29 %) and 582 Gg-S (+8.8 %), respectively, compared to the standard simplified DMS oxidation scheme. The resulting annual mean global PD direct radiative effect of DMS-derived sulfate alone is −0.11  W m−2. The enhanced PI sulfate produced via the gas-phase chemistry updates alone dampens the aerosol IRF as anticipated (−2.2 W m−2 in standard versus −1.7 W m−2 with updated gas-phase chemistry). However, high clouds in the tropics and low clouds in the Southern Ocean appear particularly sensitive to the additional aqueous-phase pathways, counteracting this change (−2.3 W m−2). This study confirms the sensitivity of aerosol IRF to the PI aerosol loading, as well as the need to better understand the processes controlling aerosol formation in the PI atmosphere and the cloud response to these changes.

scholarly journals Marine submicron aerosol gradients, sources and sinks

2016 ◽  
Vol 16 (19) ◽  
pp. 12425-12439 ◽  
Author(s):  
Darius Ceburnis ◽  
Matteo Rinaldi ◽  
Jurgita Ovadnevaite ◽  
Giovanni Martucci ◽  
Lara Giulianelli ◽  
...  
Keyword(s):  
Organic Matter ◽  
Seasonal Pattern ◽  
Ammonium Oxalate ◽  
Methanesulfonic Acid ◽  
Sea Salt ◽  
Water Soluble ◽  
Sea Spray ◽  
Sampling System ◽  
Flux Footprint ◽  
Sources And Sinks

Abstract. Aerosol principal sources and sinks over eastern North Atlantic waters were studied through the deployment of an aerosol chemistry gradient sampling system. The chemical gradients of primary and secondary aerosol components – specifically, sea salt (SS), water-insoluble organic matter (WIOM), water-soluble organic matter (WSOM), nitrate, ammonium, oxalate, amines, methanesulfonic acid (MSA) and water-soluble organic nitrogen (WSON) – were examined in great detail. Sea salt fluxes were estimated by the boundary layer box model and ranged from 0.3 to 3.5 ng m−2 s−1 over the wind speed range of 5–12 m s−1 and compared well with the derived fluxes from existing sea salt source parameterisations. The observed seasonal pattern of sea salt gradients was mainly driven by wind stress in addition to the yet unquantified effect of marine OM modifying fractional contributions of SS and OM in sea spray. WIOM gradients were a complex combination of rising and waning biological activity, especially in the flux footprint area, and wind-driven primary sea spray production supporting the coupling of recently developed sea spray and marine OM parameterisations.

scholarly journals Cloud condensation Nuclei over the Southern Ocean: wind dependence and seasonal cycles

2016 ◽  
Author(s):  
John L. Gras ◽  
Melita Keywood
Keyword(s):  
Southern Ocean ◽  
Marine Boundary Layer ◽  
Numerical Models ◽  
Cloud Condensation Nuclei ◽  
Sea Salt ◽  
Aerosol Size Distribution ◽  
Biological Source ◽  
Microphysical Properties ◽  
Coarse Mode ◽  
Aitken Mode

Abstract. Multi-decadal observations of aerosol microphysical properties from regionally representative sites can be used to challenge regional or global numerical models that simulate atmospheric aerosol. Presented here is an analysis of multi-decadal observations at Cape Grim (Australia) that characterise production and removal of the background marine aerosol in Southern Ocean marine boundary layer (MBL) on both short-term weather-related and underlying seasonal scales. A trimodal aerosol distribution comprises Aitken nuclei ( 350 nm) modes, with the Aitken mode dominating number concentration. While the integrated particle number in the MBL over the clean Southern Ocean is only weakly dependent on wind speed the different modes in the aerosol size distribution vary in their relationship with windspeed. The balance between a positive wind dependence in the coarse mode and negative dependence in the accumulation/CCN mode leads to a relatively flat wind dependence in summer and moderately strong positive wind dependence in winter. The change-over in wind dependence of these two modes occurs in a very small size range at the mode intersection, indicative of differences in the balance of production and removal in the coarse and accumulation/CCN modes. While a marine biological source of reduced sulfur appears to dominate CCN concentration over the summer months (December to February) other components contribute to CCN over the full annual cycle. Wind-generated coarse mode sea-salt is an important CCN component year round and is the second most important contributor to CCN from autumn through to mid-spring (March to November). A portion of the non-seasonal dependent contributor to CCN can clearly be attributed to wind generated sea-salt with the remaining part potentially being attributed to long range transported material. Under conditions of greater supersaturation, as expected in more convective cyclonic systems and their associated fronts, Aitken mode particles become increasingly important as CCN.

scholarly journals Impact of the particle mixing state on the hygroscopicity of internally mixed sodium chloride-ammonium sulfate single droplets: A theoretical and experimental study

2021 ◽  
Author(s):  
Yeny A. Tobon ◽  
Danielle El Hajj ◽  
Samantha Seng ◽  
Ferdaous Bengrad ◽  
Myriam Moreau ◽  
...  
Keyword(s):  
Experimental Study ◽  
Sodium Chloride ◽  
Ammonium Sulfate ◽  
Atmospheric Transport ◽  
Sea Salt ◽  
Main Constituent ◽  
Sea Salt Aerosols ◽  
Particle Mixing ◽  
Secondary Aerosols ◽  
Single Droplets

Sodium chloride (NaCl) is the main constituent of sea-salt aerosols. During atmospheric transport, sea-salt aerosols can interact with gases and other particles including secondary aerosols containing ammonium sulfate ((NH4)2SO4). This...

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