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Study of Titan's methane cycle.

The University of Arizona., Planetary Sciences.

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Study of Titan's methane cycle.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Study of Titan's methane cycle./
Author:	Penteado, Paulo Fernando.
Description:	122 p.
Notes:	Adviser: Caitlin A. Griffith.
Contained By:	Dissertation Abstracts International70-05B.
Subject:	Atmospheric Sciences. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3356413
ISBN:	9781109167344

Study of Titan's methane cycle.
Penteado, Paulo Fernando.

Study of Titan's methane cycle. - 122 p.

Adviser: Caitlin A. Griffith.

Thesis (Ph.D.)--The University of Arizona, 2009.

We developed radiative transfer models to reproduce Titan's visible and near infrared spectra, to determine the effects of the haze, and retrieve the methane abundances during Titan's current southern summer. With ground-based high resolution spectra of CH3D absorption at 1.6 mum, we measured the global CH3D abundance. Combined with observations of 8.6 mum emission of CH3D and CH4 that indicate their relative abundances, we thus determined the global CH4 abundance. We expanded on these ground-based measurements, with improved radiative transfer models based on the Huygens DISR models, and spectra which resolve the spatial variation of the CH3D lines. The profiles of CH3D thus obtained revealed that the methane abundance on the lowest 10 km of Titan's atmosphere does not vary by more than 20% over 32°S-32°N. With the extensive coverage of Cassini VIMS observations at 0.35-1.6 mum, we determined the latitudinal variation of the methane at 20-50 km and of the haze. We find an ambiguity between the methane and haze abundances, so their gradients become coupled. At the lower limit of the methane gradient, the spectral variation observed can be reproduced with no methane change, and a haze density increase of 60% between 20°S and 10°S. The largest methane variation allowed by the data, derived assuming no haze variation with latitude, is a drop of 60% over latitudes 27°S to 19°N. Our analysis indicates that the latitudinal variations in Titan's visible to near-IR albedo, the North/South Asymmetry, result primarily from variations in the thickness of the haze above 80 km altitude. The range of methane latitudinal variations allowed between 27°S to 19°N indicates temperature variations of no more than 1.5 K at 20-30 km, altitudes where the Huygens profile is saturated.

ISBN: 9781109167344Subjects--Topical Terms:

1019179
Atmospheric Sciences.

Study of Titan's methane cycle.
LDR:02892nam 2200337 a 45 001 853282
005 20100701
008 100701s2009 ||||||||||||||||| ||eng d
020 $a 9781109167344
035 $a (UMI)AAI3356413
035 $a AAI3356413
040 $a UMI $c UMI
100 1 $a Penteado, Paulo Fernando. $3 1019520
245 1 0 $a Study of Titan's methane cycle.
300 $a 122 p.
500 $a Adviser: Caitlin A. Griffith.
500 $a Source: Dissertation Abstracts International, Volume: 70-05, Section: B, page: .
502 $a Thesis (Ph.D.)--The University of Arizona, 2009.
520 $a We developed radiative transfer models to reproduce Titan's visible and near infrared spectra, to determine the effects of the haze, and retrieve the methane abundances during Titan's current southern summer. With ground-based high resolution spectra of CH3D absorption at 1.6 mum, we measured the global CH3D abundance. Combined with observations of 8.6 mum emission of CH3D and CH4 that indicate their relative abundances, we thus determined the global CH4 abundance. We expanded on these ground-based measurements, with improved radiative transfer models based on the Huygens DISR models, and spectra which resolve the spatial variation of the CH3D lines. The profiles of CH3D thus obtained revealed that the methane abundance on the lowest 10 km of Titan's atmosphere does not vary by more than 20% over 32°S-32°N. With the extensive coverage of Cassini VIMS observations at 0.35-1.6 mum, we determined the latitudinal variation of the methane at 20-50 km and of the haze. We find an ambiguity between the methane and haze abundances, so their gradients become coupled. At the lower limit of the methane gradient, the spectral variation observed can be reproduced with no methane change, and a haze density increase of 60% between 20°S and 10°S. The largest methane variation allowed by the data, derived assuming no haze variation with latitude, is a drop of 60% over latitudes 27°S to 19°N. Our analysis indicates that the latitudinal variations in Titan's visible to near-IR albedo, the North/South Asymmetry, result primarily from variations in the thickness of the haze above 80 km altitude. The range of methane latitudinal variations allowed between 27°S to 19°N indicates temperature variations of no more than 1.5 K at 20-30 km, altitudes where the Huygens profile is saturated.
590 $a School code: 0009.
650 4 $a Atmospheric Sciences. $3 1019179
650 4 $a Physics, Astronomy and Astrophysics. $3 1019521
650 4 $a Remote Sensing. $3 1018559
690 $a 0606
690 $a 0725
690 $a 0799
710 2 $a The University of Arizona. $b Planetary Sciences. $3 1019519
773 0 $t Dissertation Abstracts International $g 70-05B.
790 $a 0009
790 1 0 $a Brown, Robert H. $e committee member
790 1 0 $a Griffith, Caitlin A., $e advisor
790 1 0 $a Kursinski, E. Robert $e committee member
790 1 0 $a Tomasko, Martin G. $e committee member
790 1 0 $a Yelle, Roger $e committee member
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3356413