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Title: Intercomparison of airborne and surface-based measurements of condensation nuclei in the remote marine troposphere during ACE 1

Abstract

Intercomparisons of aerosol particle number concentrations measured with various condensation particle counters (CPCs) during the first Aerosol Characterization Experiment (ACE 1) are made to assess the accuracy of the airborne measurements. When no ambient 3{endash}10 nm diameter particles (nanoparticles) were present, median concentrations from four CPCs on the National Center for Atmospheric Research (NCAR) C-130 aircraft agreed to within {approximately}6{percent} and were highly correlated (r{gt}0.9). These instruments sampled from several different inlets and used various arrangements (e.g., tubing size and length, flow rates) to transport sampled air to the detectors. When the ambient aerosol contained significant numbers of nanoparticles, agreement between the CPCs deteriorated, likely from differences in nanoparticle transmission and detection efficiencies. During these periods, average total number concentrations measured by two ultrafine CPCs varied on average by 60{percent} with a correlation coefficient of 0.85. Intercomparisons of airborne and surface-based measurements were made during low-altitude flybys of surface measurement sites. During flybys, few nanoparticles were detected, and measured total condensation nuclei (CN) concentrations differed by roughly +5 to {minus}20{percent} (CN{sub surface}/CN{sub airborne}-1) suggesting that the airborne measurements of fine aerosols agreed with ambient surface values to within 20{percent}. Overall, we found that ambient fine particles ({approximately}20{endash}100 nm diameter) aremore » fairly insensitive to airborne sampling techniques and thus are likely to be measured accurately. Sampling losses of smaller particles, however, may lead to a significant undermeasurement of ambient CN concentrations in rare instances when the number spectra are dominated by the smallest particles. This intercomparison involves measurements made in regions absent of liquid water to avoid artifact particles produced by fragmenting water droplets. {copyright} 1999 American Geophysical Union« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [6]
  1. Environmental Chemistry Division, Brookhaven National Laboratory, Upton, New York (United States)
  2. Particle Technology Laboratory, Department of Mechanical Engineering, University of Minnesota, Minneapolis (United States)
  3. NOAA/Pacific Marine Environmental Laboratory (PMEL), Seattle, Washington (United States)
  4. School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu (United States)
  5. Department of Atmospheric Sciences, University of Washington, Seattle (United States)
  6. Department of Atmospheric Science, Colorado State University, Fort Collins (United States)
Publication Date:
OSTI Identifier:
698898
Resource Type:
Journal Article
Journal Name:
Journal of Geophysical Research
Additional Journal Information:
Journal Volume: 104; Journal Issue: D17; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; TROPOSPHERE; AEROSOLS; CONDENSATION NUCLEI; MEASURING METHODS; ACCURACY; COMPARATIVE EVALUATIONS

Citation Formats

Weber, R.J., McMurry, P.H., Bates, T.S., Clarke, A.D., Covert, D.S., and Brechtel, F.J. Intercomparison of airborne and surface-based measurements of condensation nuclei in the remote marine troposphere during ACE 1. United States: N. p., 1999. Web. doi:10.1029/1998JD100103.
Weber, R.J., McMurry, P.H., Bates, T.S., Clarke, A.D., Covert, D.S., & Brechtel, F.J. Intercomparison of airborne and surface-based measurements of condensation nuclei in the remote marine troposphere during ACE 1. United States. doi:10.1029/1998JD100103.
Weber, R.J., McMurry, P.H., Bates, T.S., Clarke, A.D., Covert, D.S., and Brechtel, F.J. Wed . "Intercomparison of airborne and surface-based measurements of condensation nuclei in the remote marine troposphere during ACE 1". United States. doi:10.1029/1998JD100103.
@article{osti_698898,
title = {Intercomparison of airborne and surface-based measurements of condensation nuclei in the remote marine troposphere during ACE 1},
author = {Weber, R.J. and McMurry, P.H. and Bates, T.S. and Clarke, A.D. and Covert, D.S. and Brechtel, F.J.},
abstractNote = {Intercomparisons of aerosol particle number concentrations measured with various condensation particle counters (CPCs) during the first Aerosol Characterization Experiment (ACE 1) are made to assess the accuracy of the airborne measurements. When no ambient 3{endash}10 nm diameter particles (nanoparticles) were present, median concentrations from four CPCs on the National Center for Atmospheric Research (NCAR) C-130 aircraft agreed to within {approximately}6{percent} and were highly correlated (r{gt}0.9). These instruments sampled from several different inlets and used various arrangements (e.g., tubing size and length, flow rates) to transport sampled air to the detectors. When the ambient aerosol contained significant numbers of nanoparticles, agreement between the CPCs deteriorated, likely from differences in nanoparticle transmission and detection efficiencies. During these periods, average total number concentrations measured by two ultrafine CPCs varied on average by 60{percent} with a correlation coefficient of 0.85. Intercomparisons of airborne and surface-based measurements were made during low-altitude flybys of surface measurement sites. During flybys, few nanoparticles were detected, and measured total condensation nuclei (CN) concentrations differed by roughly +5 to {minus}20{percent} (CN{sub surface}/CN{sub airborne}-1) suggesting that the airborne measurements of fine aerosols agreed with ambient surface values to within 20{percent}. Overall, we found that ambient fine particles ({approximately}20{endash}100 nm diameter) are fairly insensitive to airborne sampling techniques and thus are likely to be measured accurately. Sampling losses of smaller particles, however, may lead to a significant undermeasurement of ambient CN concentrations in rare instances when the number spectra are dominated by the smallest particles. This intercomparison involves measurements made in regions absent of liquid water to avoid artifact particles produced by fragmenting water droplets. {copyright} 1999 American Geophysical Union},
doi = {10.1029/1998JD100103},
journal = {Journal of Geophysical Research},
number = D17,
volume = 104,
place = {United States},
year = {1999},
month = {9}
}