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Spectral Aerosol Extinction (SpEx): A New Instrument for In situ Ambient Aerosol Extinction Measurements Across the UV/Visible Wavelength RangeWe introduce a new instrument for the measurement of in situ ambient aerosol extinction over the 300-700 nm wavelength range, the Spectral Aerosol Extinction (SpEx) instrument. This measurement capability is envisioned to complement existing in situ instrumentation, allowing for simultaneous measurement of the evolution of aerosol optical, chemical, and physical characteristics in the ambient environment. In this work, a detailed description of the instrument is provided along with characterization tests performed in the laboratory. Measured spectra of NO2 and polystyrene latex spheres agreed well with theoretical calculations. Good agreement was also found with simultaneous aerosol extinction measurements at 450, 530, and 630 nm using CAPS PMex instruments in a series of 22 tests including non-absorbing compounds, dusts, soot, and black and brown carbon analogs. SpEx can more accurately distinguish the presence of brown carbon from other absorbing aerosol due to its 300 nm lower wavelength limit compared to measurements limited to visible wavelengths. In addition, the spectra obtained by SpEx carry more information than can be conveyed by a simple power law fit that is typically defined by the use of Angstrom Exponents. Future improvements aim at lowering detection limits and ruggedizing the instrument for mobile operation.
Document ID
20160011139
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Jordan, C. E. (New Hampshire Univ. Durham, NH, United States)
Anderson, B. E. (NASA Langley Research Center Hampton, VA, United States)
Beyersdorf, A. J. (NASA Langley Research Center Hampton, VA, United States)
Corr, C. A. (Oak Ridge Associated Universities, Inc. Hampton, VA, United States)
Dibb, J. E. (New Hampshire Univ. Durham, NH, United States)
Greenslade, M. E. (New Hampshire Univ. Durham, NH, United States)
Martin, R. F. (NASA Langley Research Center Hampton, VA, United States)
Moore, R. H. (NASA Langley Research Center Hampton, VA, United States)
Scheuer, E. (New Hampshire Univ. Durham, NH, United States)
Shook, M. A. (Science Systems and Applications, Inc. Hampton, VA, United States)
Thornhill, K. L. (Science Systems and Applications, Inc. Hampton, VA, United States)
Troop, D. (Southwest Research Inst. Boulder, CO, United States)
Winstead, Edward L. (Science Systems and Applications, Inc. Hampton, VA, United States)
Ziemba, L. D. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 8, 2016
Publication Date
November 11, 2015
Publication Information
Publication: Atmospheric Measurement Techniques
Volume: 8
Issue: 11
Subject Category
Environment Pollution
Report/Patent Number
NF1676L-21219
Funding Number(s)
CONTRACT_GRANT: NA10OAR4590134
WBS: WBS 153351.05.04.01.05.01
Distribution Limits
Public
Copyright
Other