Radiative Transfer Modeling On The Atmosphere Of Uranus
Abstract
We carried out radiative transfer modeling on the atmosphere of Uranus to find the simplest 3-dimensional aerosol models that could fit the observations within measurement and modeling uncertainties. We used the Levenberg-Marquardt algorithm in combination with a radiative transfer model that accounts for Raman scattering and polarization (Sromovsky 2005, Icarus 173, 245-283) to fit 2002 HST/STIS spectra calibrated by Karkoschka and Tomasko (2009, Icarus 202, 287-309) and bandpass filter imaging observations by the HST Advanced Camera for Surveys (ACS) in 2006 and by the Wide Field/Planetary Camera 2 in 2007. Preliminary results were obtained from sampling 5 different latitudes with 4-6 emission angles and the 0.6-0.86 micron spectral range (chosen to allow conservative scattering and assumption of Beer's law), using five different methane mixing ratios consistent with the Lindal et al. (1987, JGR 92, 14987-15001) occultation solutions. The best-fit mixing ratio is near 2.9% at low latitudes and near 2.3% at middle-high latitudes, which agree with the results of Karkoschka and Tomasko (2009). A single layer of sub-micron Mie particles fits remarkably well, but a better fit is obtained with two such Mie layers, which consists of optically thin layer at 1.5 bar and optically thick layer at 2.1 2.7 bar. Both layers have optical depth increasing toward southern hemisphere.
This work was supported by grants from the Space Telescope Science Institute.- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #42
- Pub Date:
- October 2010
- Bibcode:
- 2010DPS....42.1124K