Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions

Abstract. Information on what aerosol particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which aerosol particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between −15 and −25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between −15 and −25 °C at this site for the time period studied. At −30 °C, INP number concentrations are also well correlated with number concentrations of the total aerosol particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving tracers of marine aerosols and marine biological activity indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated.

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Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-12547-2015 ◽

2015 ◽

Vol 15 (21) ◽

pp. 12547-12566 ◽

Cited By ~ 38

Author(s):

R. H. Mason ◽

M. Si ◽

J. Li ◽

C. Chou ◽

R. Dickie ◽

...

Keyword(s):

Size Distribution ◽

Marine Boundary Layer ◽

Aerosol Particles ◽

Methanesulfonic Acid ◽

Meteorological Conditions ◽

Marine Aerosols ◽

Coastal Site ◽

Carbon Particles ◽

Biological Particles ◽

Ice Nuclei

Abstract. Information on what aerosol particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which aerosol particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between −15 and −25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between −15 and −25 °C at this site for the time period studied. At −30 °C, INP number concentrations are also well correlated with number concentrations of the total aerosol particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving chemical tracers of marine aerosols and marine biological activity, sodium and methanesulfonic acid, indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated. This finding illustrates that additional measurements are needed to improve parameterizations of INPs and their subsequent climatic impacts.

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Elemental Composition of Individual Aerosol Particles Collected from the Coastal Marine Boundary Layer

Journal of the Meteorological Society of Japan Ser II ◽

10.2151/jmsj1965.74.5_585 ◽

1996 ◽

Vol 74 (5) ◽

pp. 585-591 ◽

Cited By ~ 11

Author(s):

Hideaki Mouri ◽

Ippei Nagao ◽

Kikuo Okada ◽

Seizi Koga ◽

Hiroshi Tanaka

Keyword(s):

Boundary Layer ◽

Elemental Composition ◽

Marine Boundary Layer ◽

Aerosol Particles ◽

Coastal Marine

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Depositional ice nucleation onto hydrated NaCl particles: a new mechanism for ice formation in the troposphere

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-23139-2011 ◽

2011 ◽

Vol 11 (8) ◽

pp. 23139-23167 ◽

Cited By ~ 1

Author(s):

M. E. Wise ◽

K. J. Baustian ◽

T. Koop ◽

M. A. Freedman ◽

E. J. Jensen ◽

...

Keyword(s):

Marine Boundary Layer ◽

Aerosol Particles ◽

Ice Nucleation ◽

Sea Salt ◽

Ice Formation ◽

Radiation Balance ◽

Atmospheric Conditions ◽

Hydrated Form ◽

Sea Salt Aerosol ◽

Ice Nuclei

Abstract. Sea-salt aerosol particles (SSA) are ubiquitous in the marine boundary layer and over coastal areas. Therefore SSA have ability to directly and indirectly affect the Earth's radiation balance. The influence SSA have on climate is related to their water uptake and ice nucleation characteristics. In this study, optical microscopy coupled with Raman spectroscopy was used to detect the formation of an NaCl hydrate that could form under atmospheric conditions. NaCl(s) particles deliquesced at the well established value of 75.7 ± 2.5 % RH. NaCl(aq) particles effloresced to a mixture of hydrated and non-hydrated particles at temperatures between 236 and 252 K. The aqueous particles effloresced into the non-hydrated form at temperatures warmer than 252 K. At temperatures colder than 236 K all particles effloresced into the hydrated form. The deliquescence relative humidities (DRH) of hydrated NaCl(s) particles ranged from 76.6 to 93.2 % RH. Based on the measured DRH and efflorescence relative humidities (ERH), we estimate crystalline NaCl particles could be in the hydrated form 40–80 % of the time in the troposphere. Additionally, the ice nucleating abilities of NaCl(s) and hydrated NaCl(s) were determined at temperatures ranging from 221 to 238 K. NaCl(s) particles depositionally nucleated ice at an average Sice value of 1.11 ± 0.07. Hydrated NaCl(s) particles depositionally nucleated ice at an average Sice value of 1.02 ± 0.04. When a mixture of hydrated and anhydrous NaCl(s) particles was present in the same sample, ice preferentially nucleated on the hydrated particles 100 % of the time. While both types of particles are efficient ice nuclei, hydrated NaCl(s) particles are better ice nuclei than NaCl(s) particles.

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Chemical composition and sources of coastal marine aerosol particles during the 2008 VOCALS-REx campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-5057-2014 ◽

2014 ◽

Vol 14 (10) ◽

pp. 5057-5072 ◽

Cited By ~ 5

Author(s):

Y.-N. Lee ◽

S. Springston ◽

J. Jayne ◽

J. Wang ◽

J. Hubbe ◽

...

Keyword(s):

Chemical Composition ◽

Marine Boundary Layer ◽

Aerosol Particles ◽

Sea Salt ◽

Department Of Energy ◽

Cloud Processing ◽

Aerosol Mass ◽

Coastal Marine ◽

Marine Stratus ◽

Continental Origin

Abstract. The chemical composition of aerosol particles (Dp ≤ 1.5 μm) was measured over the southeast Pacific Ocean during the VAMOS (Variability of the American Monsoon Systems) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-Rex) between 16 October and 15 November 2008 using the US Department of Energy (DOE) G-1 aircraft. The objective of these flights was to gain an understanding of the sources and evolution of these aerosols, and of how they interact with the marine stratus cloud layer that prevails in this region of the globe. Our measurements showed that the marine boundary layer (MBL) aerosol mass was dominated by non-sea-salt SO42−, followed by Na+, Cl−, Org (total organics), NH4+, and NO3−, in decreasing order of importance; CH3SO3− (MSA), Ca2+, and K+ rarely exceeded their limits of detection. Aerosols were strongly acidic with a NH4+ to SO42− equivalents ratio typically < 0.3. Sea-salt aerosol (SSA) particles, represented by NaCl, exhibited Cl− deficits caused by both HNO3 and H2SO4, but for the most part were externally mixed with particles, mainly SO42−. SSA contributed only a small fraction of the total accumulation mode particle number concentration. It was inferred that all aerosol species (except SSA) were of predominantly continental origin because of their strong land-to-sea concentration gradient. Comparison of relative changes in median values suggests that (1) an oceanic source of NH3 is present between 72° W and 76° W, (2) additional organic aerosols from biomass burns or biogenic precursors were emitted from coastal regions south of 31° S, with possible cloud processing, and (3) free tropospheric (FT) contributions to MBL gas and aerosol concentrations were negligible. The very low levels of CH3SO3− observed as well as the correlation between SO42− and NO3− (which is thought primarily anthropogenic) suggest a limited contribution of DMS to SO42− aerosol production during VOCALS.

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Size-resolved measurements of ice nucleating particles at six locations in North America and one in Europe

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-20521-2015 ◽

2015 ◽

Vol 15 (14) ◽

pp. 20521-20559 ◽

Cited By ~ 1

Author(s):

R. H. Mason ◽

M. Si ◽

C. Chou ◽

V. E. Irish ◽

R. Dickie ◽

...

Keyword(s):

North America ◽

Size Distribution ◽

Source Identification ◽

Aerosol Particles ◽

Ground Level ◽

Aerodynamic Diameter ◽

Significant Component ◽

Ice Nuclei ◽

Coarse Mode ◽

Sampling Locations

Abstract. Detailed information on the size of ice nucleating particles (INPs) may be useful in source identification, modeling their transport in the atmosphere to improve climate predictions, and determining how effectively or ineffectively instrumentation used for quantifying INPs in the atmosphere captures the full INP population. In this study we report immersion-mode INP number concentrations as a function of size at six ground sites in North America and one in Europe. The lowest INP number concentrations were observed at Arctic and alpine locations and the highest at suburban and agricultural locations, consistent with previous studies of INP concentrations in similar environments. We found that 91, 79, and 63 % of INPs had an aerodynamic diameter > 1 μm at ice activation temperatures of −15, −20, and −25 °C, respectively, when averaging over all sampling locations. In addition, 62, 55, and 42 % of INPs were in the coarse mode (> 2.5 μm) at ice activation temperatures of −15, −20, and −25 °C, respectively, when averaging over all sampling locations. These results are consistent with six out of the seven studies in the literature that have focused on the size distribution of INPs in the atmosphere. Taken together, these findings strongly suggest that supermicron and coarse mode aerosol particles are a significant component of the ice nuclei population in many different ground-level environments. Further size-resolved studies of INPs as a function of altitude are required.

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Chemical composition and sources of coastal marine aerosol particles during the 2008 VOCALS-REx campaign

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-26043-2013 ◽

2013 ◽

Vol 13 (10) ◽

pp. 26043-26115

Author(s):

Y.-N. Lee ◽

S. Springston ◽

J. Jayne ◽

J. Wang ◽

J. Hubbe ◽

...

Keyword(s):

Chemical Composition ◽

Marine Boundary Layer ◽

Aerosol Particles ◽

Sea Salt ◽

Strongly Correlated ◽

Cloud Processing ◽

Aerosol Mass ◽

Coastal Marine ◽

Marine Stratus ◽

Continental Origin

Abstract. The chemical composition of aerosol particles (Dp &leq; 1.5 μm) was measured over the southeast Pacific ocean during the VOCALS-REx experiment between 16~October and 15 November 2008 using the US DOE G-1 aircraft. The objective of these flights was to gain an understanding of the sources and evolution of these aerosols, and how they interacted with the marine stratus cloud layer that prevails in this region of the globe. Our measurements showed that the marine boundary layer (MBL) aerosol mass was dominated by non-sea-salt SO42−, followed by Na+, Cl−, Org, NH4+, and NO3−, in decreasing order of importance; CH3SO3−1 (MSA), Ca2+, and K+ rarely exceeded their limits of detection of ~0.05 and ~0.15 μg m−3 for anions and cations, respectively. The aerosols were strongly acidic as the NH4+ to SO42− equivalence ratio was typically < 0.3; this inferred acidity is corroborated by the conductivity of aqueous samples collected by the PILS. Sea-salt aerosol (SSA) particles, represented by NaCl, showed Cl− deficits caused by both HNO3 and H2SO4, and were externally mixed with SO42− particles as the AMS detected no NO3− whilst uptake of HNO3 occurred only on SSA particles. The SSA loading as a function of wind speed agreed with that calculated from published relationships, and contributed only a small fraction of the total accumulation mode particle number. Vertical distribution of MBL SSA particles (Dp &leq; ~1.5 μm) was uniform, suggesting a very limited dilution from entrainment of free tropospheric (FT) air. It was inferred that because all of the aerosol species (except SSA) exhibited a strong land-to-sea gradient, they were of continental origin. Comparison of relative changes in median values using LOWESS fits as proxies suggests that (1) an oceanic source of NH3 is present between 72° W and 76° W, and (2) additional organic aerosols from biomass burns or biogenic precursors were emitted from coastal regions south of 31° S, with possible cloud processing, and (3) FT contributions to MBL gas and aerosols were negligible. Positive Matrix Factorization analysis of organic aerosol mass spectra obtained with the AMS showed an HOA on 28 October 2008 but not on 6 November 2008 that we attribute to a more extensive cloud processing on the later date. A highly oxidized OOA factor resembling fulvic acid was found associated with anthropogenic and biogenic sources as well as long range transported biomass burn plumes in the FT air. A sulfur-containing OOA factor identified as MSA was strongly correlated with SO42−, hence anthropogenic. The very low levels of CH3SO3− observed suggest a limited contribution of DMS to SO42− aerosols production during VOCALS.

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