Comparison of Size Changes of Asian Dust Particles Caused by Sea Salt and Sulfate

Zhang, Daizhou; Iwasaka, Yasunobu

doi:10.2151/jmsj.84.939

Cited by 11 publications

(7 citation statements)

References 24 publications

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“…To obtain the growth of dust particles due to sea salt adhering, a linear relation between the relative growth of dust particles and their mixture degree, RelativeGrowth = 0.4198 MixtureDegree − 0.0432 with the confidence R 2 = 0.9321, is applied; where the RelativeGrowth of a particle is defined as the ratio of its growth due to sea salt to its diameter and the MixtureDegree of a particle is defined as the ratio of the relative mass of sodium and chlorine to that of sodium, chlorine, aluminium, silicon and iron in the particle. This relation was derived from the data published in a previous paper (Zhang and Iwasaka, 2006).…”

Section: Methodssupporting

confidence: 92%

“…The size and density of a particle are two key parameters in determining its settling velocity. Field measurements have shown that sea salt emitted from the ocean could significantly change dust particles and cause the particles to grow in size (Andreae et al, 1986; Zhang and Iwasaka, 2004, 2006). Clearly, this kind of growth can cause changes in the settling velocity of particles, thus modifying dust deposition and making the process of dust settling to the sea surface fundamentally different from that in the continental atmosphere.…”

Section: Introductionmentioning

confidence: 99%

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Effect of sea salt on dust settling to the ocean

Zhang

2008

Tellus B: Chemical and Physical Meteorology

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A B S T R A C T Dust particles frequently become mixtures of mineral dust and sea salt during their transport in the marine boundary layer, consequently growing in size, which causes changes in their settling velocities. In this study, the effect of sea salt on the gravitational settling of dust particles is investigated. Results show that the adhering of sea salt to dust particles can dramatically increase the gravitational settling of the particles, in particular if the particles become larger than 3-4 μm. Estimates with the observational data from six dust events in southwestern Japan revealed that, due to sea salt adhering, the gravitational settling flux of mineral dust increased approximately 14-17% in well-mixed events and 4-6% in less-mixed events, indicating a potential significant effect of sea salt on dust settling and the importance of considering this effect in the schemata of particle gravitational settling when mapping dust flux to the ocean.

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Section: Methodssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Effect of sea salt on dust settling to the ocean

Zhang

2008

Tellus B: Chemical and Physical Meteorology

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“…Notice that this is completely different from the sulfate in fine particles (diameter < 1 μ m) which had a higher SO 4 2− /Ca 2+ mass ratio (16.2) and a much higher mass percentage of sulfate (>30%) than the coarse particles in the same case. It has been proven that there were usually a large number of sulfur‐containing calcium‐rich particles in the fine size range in long‐range transported Asian dust plumes [ Matsuki et al , 2005; Zhang and Iwasaka , 2006].…”

Section: Resultsmentioning

confidence: 99%

Soil‐derived sulfate in atmospheric dust particles at Taklimakan desert

Zhang

Cao

et al. 2012

Geophysical Research Letters

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Dust‐associated sulfate is believed to be a key species which can alter the physical and chemical properties of dust particles in the atmosphere. Its occurrence in the particles has usually been considered to be the consequence of particles' aging in the air although it is present in some crustal minerals. Our observation at the north and south edge of Taklimakan desert, one of the largest dust sources in the Northern Hemisphere, during a dust episode in April 2008 revealed that sulfate in atmospheric dust samples most likely originated directly from surface soil. Its TSP, PM10 and PM2.5 content was proportional to samples' mass and comprised steadily about 4% in the differently sized samples, the ratio of elemental sulfur to iron was approximately constant 0.3, and no demonstrable influence of pollutants from fossil fuel combustion and biomass burning was detected. These results suggest that sulfate could be substantially derived from surface soil at the desert area and the lack of awareness of this origin may impede accurate results in any investigation of atmospheric sulfur chemistry associated with Taklimakan dust and its subsequent local, regional and global effects on the atmosphere.

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“…In this study, the increasing trends of DDV Fe and DDV Al during the fall/winter months are consistent with marine particle growth during increased humidity and sea salt aerosol production. Over the Pacific, dust particles in the marine boundary layer are commonly observed to form larger aggregates through the collisions with sea‐salt particles and coagulations with N or S pollutants [ Andreae et al , 1986; Zhang et al , 2005; Zhang and Iwasaka , 2006]. Atmospheric factors could include increased turbulence, humidity and sea salt particle burdens as observed at Puerto Rico in the summer that may similarly explain the increasing trend of DDV Fe and DDV Al during the later (fall/winter) seasons at Bermuda as well [ Maring et al , 2003].…”

Section: Discussionmentioning

confidence: 99%

Atmospheric Fe deposition modes at Bermuda and the adjacent Sargasso Sea

Tian

Ollivier

Véron³

et al. 2008

Geochem Geophys Geosyst

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[1] The atmospheric fluxes of Fe and Al were determined from bulk (wet + dry) plus wet only deposition and aerosol samples collected at Bermuda from 1999 to 2001. During the sampling period, dry deposition accounted for majority (>70%) of total Fe deposition estimated by both modeled and measured means. This contrasts the North Pacific, where generally wet dominates dry deposition. This may be caused by the size and proximity of continental dust sources and seasonal patterns of precipitation to the North Atlantic. Comparing time series measurement of wet soluble Fe deposition indicates that the North Atlantic Oscillation (NAO) may impact the deposition mode of Fe in these areas. The dry deposition velocities of Fe-bearing aerosols (DDV Fe ) were estimated from paired averages of measured dry deposition (bulk-wet fluxes) divided by corresponding aerosol concentrations, and a seasonal trend was observed. During the summer months of 1999, the DDV Fe ranged from 0.1 to 0.3 cm s À1 ; yet, during the fall and winter months, the DDV Fe ranged from 2.0 to 6.0 cm s À1 . It is hypothesized that with increased humidity and wind speeds at Bermuda during fall and winter, mineral aerosol particles could be internally mixed with sea salt and gaseous S and N pollutants to increase effective particle sizes. Such marine particle aggregation is reported elsewhere and could seasonally increase the apparent dry deposition velocity of mineral aerosols.

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Comparison of Size Changes of Asian Dust Particles Caused by Sea Salt and Sulfate

Cited by 11 publications

References 24 publications

Effect of sea salt on dust settling to the ocean

Effect of sea salt on dust settling to the ocean

Soil‐derived sulfate in atmospheric dust particles at Taklimakan desert

Atmospheric Fe deposition modes at Bermuda and the adjacent Sargasso Sea

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