Data from: Long wavelength topography of Io and predicted isostatic topography resulting from spatial variation in Io's tidal heating
Data files
Apr 09, 2024 version files 236.29 KB
Abstract
After deriving equations that describe the response of isostatic, long-wavelength topography to spatial variation of Io's tidal heating, we use these equations to plot this response as a function of tidal heat variation. We compare the possible range of topographic amplitude to the observed global shape of Io (after subtraction of its hydrostatic shape).
README: Data from: Long wavelength topography of Io and predicted isostatic topography resulting from spatial variation in Io's tidal heating
https://doi.org/10.5061/dryad.b8gtht7k6
We include Io limb profile topography and the spherical harmonic coefficients of topography in degrees 3 and 4. Then, we utilize our derived equations to demonstrate a model of topography as a function of variation in tidal heating for comparison.
Description of the data and file structure
We include 2 datasets and one program script.
ThomasLimbP.txt contains Io limb profile topography, and is provided courtesy of Peter Thomas. The Galileo image used for each profile is listed in Table 1 of White et al. (2014, JGR: Planets 119(6), pp. 1276-1301). All the profiles are included in the same file, where the first column is the longitude (°W), the second column is latitude (°N), and the third column is the topography in km with respect to the reference ellipsoid defined in Thomas et al. (1998, *Icarus 13*5(1), pp. 175-180).
Io_SphHarmCoef_Norm.txt contains spherical harmonic coefficients of topography in degrees 3 and 4. These were generated from the limb profile topography using the method summarized in White et al. (2014) with smoothing parameter r=3*10^7. The columns are as follows: degree l, order m, index 1 or -1, coefficient, uncertainty. The index is 1 for the C_{l,m} coefficient and -1 for the S_{l,m} coefficient. The spherical harmonic coefficient is listed in km, as normalized by the method described in Nimmo et al. (2011, JGR: Planets 116(E11)). Note: some coefficients may feature a sign error as described in Nimmo et al. (2013, JGR: Planets 118(12)). The correct C coefficients must be multiplied by (-1)^m, while the correct S coefficients must be multiplied by (-1)^(m+1).
Sharing/Access information
n/a
Code/Software
Use python 3 to run io_heat_flux_topography.py and reproduce the figure from our paper. Required modules include numpy and matplotlib.
Methods
The dataset for Io limb topography used in White et al. (2014, JGR: Planets, 119(6)) has been provided courtesy of Peter Thomas. This topography is measured with respect to the reference ellipsoid of Io (Thomas et al., 1998, Icarus 135(1)).
Spherical harmonic degree 3 and 4 coefficients were generated with the method summarized in White et al. (2014), using smoothing parameter r = 3*10^7.