Observations of the spectral dependence of linear particle depolarization ratio of aerosols using NASA Langley airborne High Spectral Resolution Lidar
Artikel i vetenskaplig tidskrift, 2015

Linear particle depolarization ratio is presented for three case studies from the NASA Langley airborne High Spectral Resolution Lidar-2 (HSRL-2). Particle depolarization ratio from lidar is an indicator of non-spherical particles and is sensitive to the fraction of non-spherical particles and their size. The HSRL-2 instrument measures depolarization at three wavelengths: 355, 532, and 1064 nm. The three measurement cases presented here include two cases of dust-dominated aerosol and one case of smoke aerosol. These cases have partial analogs in earlier HSRL-1 depolarization measurements at 532 and 1064 nm and in literature, but the availability of three wavelengths gives additional insight into different scenarios for non-spherical particles in the atmosphere. A case of transported Saharan dust has a spectral dependence with a peak of 0.30 at 532 nm with smaller particle depolarization ratios of 0.27 and 0.25 at 1064 and 355 nm, respectively. A case of aerosol containing locally generated wind-blown North American dust has a maximum of 0.38 at 1064 nm, decreasing to 0.37 and 0.24 at 532 and 355 nm, respectively. The cause of the maximum at 1064 nm is inferred to be very large particles that have not settled out of the dust layer. The smoke layer has the opposite spectral dependence, with the peak of 0.24 at 355 nm, decreasing to 0.09 and 0.02 at 532 and 1064 nm, respectively. The depolarization in the smoke case may be explained by the presence of coated soot aggregates. We note that in these specific case studies, the linear particle depolarization ratio for smoke and dust-dominated aerosol are more similar at 355 nm than at 532 nm, having possible implications for using the particle depolarization ratio at a single wavelength for aerosol typing.

Författare

S. P. Burton

National Aeronautics and Space Administration (NASA)

J. W. Hair

National Aeronautics and Space Administration (NASA)

Michael Kahnert

Chalmers, Rymd- och geovetenskap, Global miljömätteknik

R. A. Ferrare

National Aeronautics and Space Administration (NASA)

C. A. Hostetler

National Aeronautics and Space Administration (NASA)

A. L. Cook

National Aeronautics and Space Administration (NASA)

D. B. Harper

National Aeronautics and Space Administration (NASA)

T. A. Berkoff

National Aeronautics and Space Administration (NASA)

S. T. Seaman

National Institute of Aerospace

National Aeronautics and Space Administration (NASA)

J. E. Collins

Science Systems and Applications, Inc.

National Aeronautics and Space Administration (NASA)

M. A. Fenn

National Aeronautics and Space Administration (NASA)

Science Systems and Applications, Inc.

R. R. Rogers

National Aeronautics and Space Administration (NASA)

Lord Fairfax Community College

Atmospheric Chemistry and Physics

1680-7316 (ISSN) 1680-7324 (eISSN)

Vol. 15 23 13453-13473

Aerosolpartiklarnas direkta klimatpåverkan i global jordsystemmodellering

Vetenskapsrådet (VR) (2011-3346), 2011-10-26 -- 2014-10-26.

Ämneskategorier (SSIF 2011)

Meteorologi och atmosfärforskning

DOI

10.5194/acp-15-13453-2015

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Senast uppdaterat

2025-03-09