Aerosol Chemical Composition determined using the PILSIC on the G1 during 2005 MASE

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Aerosol Chemical Composition determined using the
PILS-IC on the G1 during 2005 MASE

• Yin-Nan Lee
• Atmospheric Sciences Division
• Brookhaven National Laboratory
• Stephen Springston, BNL
• Gunnar Senum, BNL
• John Hubbe, PNNL
• John Jayne, Aerodyne
• Mike Alexander, PNNL
• Jian Wang, BNL
• Peter Daum, BNL
• Jim Hudson, DRI
• Atmospheric Science Program Science Meeting
• Oct. 31 - Nov. 1, 2005

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Objectives

• To understand the aerosol-CCN-cloud-precipita
  tion system and its radiative effects in a
  coastal marine environment by investigating
• Aerosol optical properties as a function of size
  and chemical composition
• Relationship between CCN properties and aerosol
  size and chemical composition
• Relationship between cloud microphysics and
  aerosol properties
• Relationship between drizzle formation and cloud
  microphysics
• Radiative properties of marine stratus and extent
  of human influences

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2005 Marine Stratus Experiment

• A field campaign in California supported by ARM
  and ASP
• ARM Mobile Facility - Point Reyes
• SIRPAS Twin Otter Marina
• DOE G1 Rancho Cordova
• G1 conducted 12 research flights between 7/6 and
  7/27
• Measurements made on the G1
• Aerosol number concentration, size distribution,
  light scattering, light absorption, CCN
  concentration and spectrum
• Aerosol bulk (PILS-IC) and size resolved (AMS)
  chemical composition
• Cloud droplet size distribution, liquid water
  content
• Met and aircraft parameters

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Products of the PILS-IC analysis during 2005 MASE

• Anions Cl-, NO3-, SO42-, CH3SO3-,
  formate/acetate, oxalate
• Cations Na, NH4, Mg2, K, Ca2
• Time resolution 4.0 min
• Sample integration time 4.0 min nominal
• Limit of detection 0.05 µg m-3
• Measurement uncertainty 7-15

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Distributions of aerosol ionic Species (marine
only)
Na
Cl
NH4
SO4
MSA
NO3
Mg
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Examining the observed compositionregarding

• Sources
• Effects on optical properties
• Possible cloud effects on aerosol measurements
• Organic content, distribution and role

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Total ion concentration and the contribution of
NaCl
Total ion concentration, µg/m3
NaCl mass fraction,
Wind speed, m/s Alt lt 100 m
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Ion and Charge Balance
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Comparison of SSA and seawater composition
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Comparison of NH4 to SO42- and NO3-
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Vertical distributions of O3 and SO2
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Vertical distributions of aerosol ionic species
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Relationship between light scattering coefficient
and pcasp number concentration
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Aerosol light scattering coefficient as a
function of number concentration and NaCl content
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Aerosol light scattering in cloud vs free air
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Relationship among light scattering, number
concentration and light absorption
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Relationship between light scattering coefficient
and ion mass concentration
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Relationship among light scattering, number
concentration and organic concentration
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Correlations of organics and inorganic
ions(cloud free air only)
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Tentative Remarks

• NaCl contributes significantly to aerosol
  inorganic ionic mass over the marine environment.
• SSA particles are important contributors to light
  scattering due primarily to their large sizes.
• Inferred organic component comprises an important
  portion of the aerosol mass.
• Because both particle numbers and the organic
  mass were significantly reduced in cloud, organic
  aerosol particles appear to play an important
  role as CCN.