Comparison of modeled backscatter using measured aerosol microphysics with focused CW lidar data over Pacific

Srivastava, Vandana; Clarke, A. D.; Jarzembski, Maurice A.; Rothermel, Jeffry

doi:10.1029/97jd00604

Cited by 7 publications

(13 citation statements)

References 31 publications

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“…The ratio of RCN to total CN defines the RefRatio as an indicator of airmass variability since it is not directly dependent on aerosol concentration (Clarke 1993). We have observed that polluted and continental aerosol often have ratios near about 0.8 whereas more pristine regions tend to be far more volatile with low ratios often approaching zero (Clarke et al 1997). Variability in the refractory component also appears to reflect sources of continental combustion (soot-black carbon, fly ash, some organics) or dust aerosol, whereas, in clean marine regions this component is generally lower (Clarke et al 1997).…”

Section: Discriminatormentioning

confidence: 91%

“…We have observed that polluted and continental aerosol often have ratios near about 0.8 whereas more pristine regions tend to be far more volatile with low ratios often approaching zero (Clarke et al 1997). Variability in the refractory component also appears to reflect sources of continental combustion (soot-black carbon, fly ash, some organics) or dust aerosol, whereas, in clean marine regions this component is generally lower (Clarke et al 1997). The ''ultrafine CN'' (UCN) counter (TSI 3025) was used to count all particles between 0.003-3.0 m. We also provide the differential measurement between CN and UCN instruments (UCN-CN) for particle sizes in the 3-12 Ϯ 2 nm size range.…”

Section: Discriminatormentioning

confidence: 99%

“…However, it is clear that MBL aerosol and FT aerosol are coupled through mixing and entrainment (Clarke and Porter 1993;Clarke et al 1996;Covert et al 1996;Clarke et al 1997;Solazzo et al 2000;Clarke et al 2001, hereafter C01). Moreover, case studies have revealed natural sources of aerosol production aloft (Clarke et al 1999a,b) consistent with model results (Raes et al 1995) as well as numerous cases of plumes undergoing long-range transport (C01; Browell et al 2001, manuscript submitted to J. Geophys.…”

Section: J O U R N a L O F T H E A T M O S P H E R I C S C I E N C E Smentioning

confidence: 99%

“…Aerosol physiochemical measurements were also made over a broad range of spatial and temporal scales, producing large aerosol datasets that provided empirical links between these properties and aerosol backscatter at various lidar wavelengths (Srivastava et al 1997).…”

Section: A Aircraft Experiments Over the Pacificmentioning

confidence: 99%

“…Size distribution data from the OPC/ Thermo. Optic Aerosol Discriminator instrumentation was used to calculate aerosol optical properties for direct intercomparison with the lidar backscatter signal (Srivastava et al 1997;Cutten et al 1996) while the CN and UCN counters were used to identify air mass characteristics that could reveal both regions of particle production and the relationship of aerosol properties to various meteorological conditions (Clarke 1993). One example of the kind of data obtained is the GLOBE flight from Darwin to Tokyo in the western Pacific that exhibited the range of aerosol variability and scales suggestive of zonal features.…”

Section: Aerosol Survey Data a Globe-2mentioning

confidence: 99%

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A Pacific Aerosol Survey. Part I: A Decade of Data on Particle Production, Transport, Evolution, and Mixing in the Troposphere*

2002

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Integration of extensive aerosol data collected during the past decade around the Pacific basin provides a preliminary assessment of aerosol microphysics for this region and cycling of aerosol in the troposphere. These include aircraft-based data collected as part of numerous field experiments supported by the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the National Oceanic and Atmospheric Administration (NOAA) [Global Backscatter Experiment (GLOBE), First Aerosol Characterization Experiment (ACE-1), Pacific Exploratory Mission (PEM)-Tropics A and B]. Although these experiments had diverse goals, most included extensive data on aerosol size distributions, optical properties (light scattering and light absorption), and chemistry. Vertical profiles of aerosol concentration, size distribution, and light scattering were used to characterize vertical structure from 70ЊS to 70ЊN. The in situ data are placed in the context of meteorological regimes over the Pacific as well as processes associated with particle formation, growth, and evolution, and include dust, pollution, sea salt, sulfates, and clean cloud-processed air. The Tropics commonly have low aerosol mass but very high number concentrations in the upper free troposphere (FT) that appear to form from sulfuric acid (nucleation) in convective regions and near cloud edges. These age and subside to become effective cloud condensation nuclei (CCN) when mixed into the marine boundary layer. Fewer number but larger aerosol are more evident in the midlatitude FT. These can often be internally mixed and with a nonvolatile core indicative of black carbon with volatile components (sulfate, organics, etc.). In the North Pacific springtime a combustion-derived aerosol is frequently found associated with the same meteorology that transports ''dust events.'' Both constituents may dominate the scattering and absorption properties of the aerosol even though the increase in large dust particles in such events generally dominates the mass. The FT in the subtropics tends to exhibit frequent and marked transitions and mixing between these clean and continental aerosol types.

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Section: Discriminatormentioning

confidence: 91%

Section: Discriminatormentioning

confidence: 99%

Section: J O U R N a L O F T H E A T M O S P H E R I C S C I E N C E Smentioning

confidence: 99%

Section: A Aircraft Experiments Over the Pacificmentioning

confidence: 99%

Section: Aerosol Survey Data a Globe-2mentioning

confidence: 99%

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A Pacific Aerosol Survey. Part I: A Decade of Data on Particle Production, Transport, Evolution, and Mixing in the Troposphere*

2002

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Scattering in the Atmosphere

Vaughan¹

2002

Scattering

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Aerosol layers over the Pacific Ocean: Vertical distributions and optical properties as observed by multiwavelength airborne lidars

et al. 2002

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[1] Scattering properties of tropospheric aerosol layers were observed with airborne lidars during the Global Backscatter Experiment (GLOBE) airborne campaigns covering a wide range of latitude and longitude over the Pacific Ocean. Lidar data at 0.532, 1.064, 1.54, and 9.25 mm wavelengths are used to study the vertical profiles and optical properties of the marine boundary layer (MBL) as well as elevated dust layers due to transport of material from Asia. The lidars were calibrated to provide absolute aerosol backscatter coefficients at their respective wavelengths. The lidar data are compared with predictions based on commonly used dust and sea salt aerosol refractive index and size distribution parameters. Published observations of aerosol characteristics from onboard in situ sensors are used to verify locations where mineral dust aerosol dominated the aerosol optical properties in the free troposphere. Relative humidity has a major impact on the observed MBL aerosol scattering characteristics. The multiwavelength observations of the dust layers are consistent with the assumption that for the particle size range that dominates the scattering properties the particle size distribution varies little over 10 3 km transport distances and is not strongly dependent on altitude. A nonsphericity effect on the dust scattering, in particular the suppression of backscattering at the shorter lidar wavelengths, is discussed in the context of data comparisons with model predictions. The observations of the sea salt aerosol scattering in the remote MBL indicate that at altitudes above 150 m in optically clear conditions the influence of the supermicron coarse mode is minor compared with that of the submicron accumulation mode.

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Comparison of modeled backscatter using measured aerosol microphysics with focused CW lidar data over Pacific

Cited by 7 publications

References 31 publications

A Pacific Aerosol Survey. Part I: A Decade of Data on Particle Production, Transport, Evolution, and Mixing in the Troposphere*

A Pacific Aerosol Survey. Part I: A Decade of Data on Particle Production, Transport, Evolution, and Mixing in the Troposphere*

Scattering in the Atmosphere

Aerosol layers over the Pacific Ocean: Vertical distributions and optical properties as observed by multiwavelength airborne lidars

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