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Title: Using spectral methods to obtain particle size information from optical data: applications to measurements from CARES 2010

Here, multi-wavelength in situ aerosol extinction, absorption and scattering measurements made at two ground sites during the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are analyzed using a spectral deconvolution method that allows extraction of particle-size-related information, including the fraction of extinction produced by the fine-mode particles and the effective radius of the fine mode. The spectral deconvolution method is typically applied to analysis of remote sensing measurements. Here, its application to in situ measurements allows for comparison with more direct measurement methods and validation of the retrieval approach. Overall, the retrieved fine-mode fraction and effective radius compare well with other in situ measurements, including size distribution measurements and scattering and absorption measurements made separately for PM 1 and PM 10, although there were some periods during which the different methods yielded different results. One key contributor to differences between the results obtained is the alternative, spectrally based definitions of fine and coarse modes from the optical methods, relative to instruments that use a physically defined cut point. These results indicate that for campaigns where size, composition and multi-wavelength optical property measurements are made, comparison of the results can result in closure or can identify unusual circumstances. The comparisonmore » here also demonstrates that in situ multi-wavelength optical property measurements can be used to determine information about particle size distributions in situations where direct size distribution measurements are not available.« less
 [1] ;  [2] ;  [2] ; ORCiD logo [3] ;  [4] ; ORCiD logo [5] ;  [6] ;  [7] ; ORCiD logo [5]
  1. Portland State Univ., Portland, OR (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. Portland State Univ., Portland, OR (United States); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
  4. Univ. of California, Davis, CA (United States); Air Sciences, Inc., Portland, OR (United States)
  5. Univ. of California, Davis, CA (United States)
  6. Univ. of California, Davis, CA (United States); Swiss Federal Lab. for Materials Science and Technology, Dubendorf (Switzerland)
  7. Univ. de Sherbrooke, Sherbrooke (Canada)
Publication Date:
Report Number(s):
Journal ID: ISSN 1680-7324
Grant/Contract Number:
SC0008937; AC05-76RL01830
Accepted Manuscript
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 18; Journal Issue: 8; Journal ID: ISSN 1680-7324
European Geosciences Union
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
OSTI Identifier: