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Title: Speckle Imaging of Titan at 2 microns: Surface Albedo,Haze Optical Depth, and Tropospheric Clouds 1996-1998

Abstract

We present results from 14 nights of observations of Titan in 1996-1998 using near-infrared (centered at 2.1 microns) speckle imaging at the 10-meter W.M. Keck Telescope. The observations have a spatial resolution of 0.06 arcseconds. We detect bright clouds on three days in October 1998, with a brightness about 0.5% of the brightness of Titan. Using a 16-stream radiative transfer model (DISORT) to model the central equatorial longitude of each image, we construct a suite of surface albedo models parameterized by the optical depth of Titan's hydrocarbon haze layer. From this we conclude that Titan's equatorial surface albedo has plausible values in the range of 0-0.20. Titan's minimum haze optical depth cannot be constrained from this modeling, but an upper limit of 0.3 at this wavelength range is found. More accurate determination of Titan's surface albedo and haze optical depth, especially at higher latitudes, will require a model that fully considers the 3-dimensional nature of Titan's atmosphere.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
15013995
Report Number(s):
UCRL-JRNL-202602
TRN: US200803%%1046
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Published in: Icarus, vol. 169, n/a, May 1, 2004, pp. 429-439
Additional Journal Information:
Journal Volume: 169
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ALBEDO; BRIGHTNESS; CLOUDS; HYDROCARBONS; SIMULATION; SPATIAL RESOLUTION; WAVELENGTHS

Citation Formats

Gibbard, S G, Gavel, D, Ghez, A M, de Pater, I, Max, C E, Young, E F, Roe, H G, Macintosh, B A, and McKay, C P. Speckle Imaging of Titan at 2 microns: Surface Albedo,Haze Optical Depth, and Tropospheric Clouds 1996-1998. United States: N. p., 2004. Web. doi:10.1016/j.icarus.2003.12.026.
Gibbard, S G, Gavel, D, Ghez, A M, de Pater, I, Max, C E, Young, E F, Roe, H G, Macintosh, B A, & McKay, C P. Speckle Imaging of Titan at 2 microns: Surface Albedo,Haze Optical Depth, and Tropospheric Clouds 1996-1998. United States. https://doi.org/10.1016/j.icarus.2003.12.026
Gibbard, S G, Gavel, D, Ghez, A M, de Pater, I, Max, C E, Young, E F, Roe, H G, Macintosh, B A, and McKay, C P. 2004. "Speckle Imaging of Titan at 2 microns: Surface Albedo,Haze Optical Depth, and Tropospheric Clouds 1996-1998". United States. https://doi.org/10.1016/j.icarus.2003.12.026. https://www.osti.gov/servlets/purl/15013995.
@article{osti_15013995,
title = {Speckle Imaging of Titan at 2 microns: Surface Albedo,Haze Optical Depth, and Tropospheric Clouds 1996-1998},
author = {Gibbard, S G and Gavel, D and Ghez, A M and de Pater, I and Max, C E and Young, E F and Roe, H G and Macintosh, B A and McKay, C P},
abstractNote = {We present results from 14 nights of observations of Titan in 1996-1998 using near-infrared (centered at 2.1 microns) speckle imaging at the 10-meter W.M. Keck Telescope. The observations have a spatial resolution of 0.06 arcseconds. We detect bright clouds on three days in October 1998, with a brightness about 0.5% of the brightness of Titan. Using a 16-stream radiative transfer model (DISORT) to model the central equatorial longitude of each image, we construct a suite of surface albedo models parameterized by the optical depth of Titan's hydrocarbon haze layer. From this we conclude that Titan's equatorial surface albedo has plausible values in the range of 0-0.20. Titan's minimum haze optical depth cannot be constrained from this modeling, but an upper limit of 0.3 at this wavelength range is found. More accurate determination of Titan's surface albedo and haze optical depth, especially at higher latitudes, will require a model that fully considers the 3-dimensional nature of Titan's atmosphere.},
doi = {10.1016/j.icarus.2003.12.026},
url = {https://www.osti.gov/biblio/15013995}, journal = {Published in: Icarus, vol. 169, n/a, May 1, 2004, pp. 429-439},
number = ,
volume = 169,
place = {United States},
year = {2004},
month = {2}
}

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