DOI: 10.5281/zenodo.13800082
title: Model of Saturn's gravity field based on Slepian and spherical harmonic functions

description:       Corresponding Dataset for "Saturn's small-scale winds revealed by                       its high-degree gravity field"                                 README FILE                                  VERSION 2                                  Seho Kim                              October 21, 2024                          Jet Propulsion Laboratory                      California Institute of Technology

=============================================================================INTRODUCTION=============================================================================

   This dataset contains a gravity field model of Saturn derived from CassiniGravity Science Experiment data collected from May 2017 to July 2017 (Rev 273,274, 278, 280, 284), using a Slepian-combined approach. This dataset is intended to be paired with the following article submitted to GeophysicalResearch Letters:

     S. Kim, M. Parisi, C. R. Mankovich, D. R. Buccino, O. Yang, "Saturn's small-scalewinds revealed by its high-degree gravity field", Geophysical Research Letters, 2024 (submitted Oct 2024).

=============================================================================FILE FORMAT=============================================================================

    This dataset contains ASCII plain-text files that are given with the "*.txt" extension and a MAT file that is given with the "*.mat" extension.The ASCII files are human-readable, comma-separated text files and the MAT fileis a binary file readable by MATLAB releases R14 (Version 7.0) or later.

=============================================================================ARCHIVE INFORMATION=============================================================================

    This archive contains a total of two data products in ASCII plain-text format and a total of one data product in MAT file format.

The following describes these data files in more details:

1)  Slepian functions     -------------------------------------------------------------------------    TXT_FILENAME = 1_Slepian_functions.txt    This file contains the Slepian functions defined using spherical     harmonics J2 to J41 within a latitudinal band of 32 degrees south and     32 degrees north.    The first column represents the planetocentric Saturnian latitude (units    of degrees).    The second to fifth columns represent the values of the normalized Slepian    functions (S13 to S15), as a function of latitude (no units).

2)  Saturn gravity field solution with spherical harmonics and Slepians    -------------------------------------------------------------------------    TXT_FILENAME = 2_Saturn_gravity harmonics.txt    This files contains the Cassini gravity field solution for Saturn, using    data from Rev 273, Rev 274, Rev 278, Rev 280, Rev 284, in terms of    spherical harmonic coefficients (J2-J12) and Slepian coefficients (s13-s15).    'NaN' represents an undefined/empty value.    The first column represents the names of the gravity field coefficient.     The second column represents the rigid-body rotation model for each    gravity coefficients (no units).     The third column represent the estimated central values of the normalized     spherical harmonics and Slepian coefficients from Cassini observations    (no units).    The fourth column represents the wind-induced contributions of the gravity    potentials calculated by the third column minus the second column (no units).    The fifth column represents the thermal wind balance prediction for each    gravity coefficients (no units).    The sixth column represents the estimated formal uncertainty for each    gravity coefficients (no units).    The seventh column represents the estimated formal uncertainty, multiplied    by 3, for each gravity coefficients (no units).    

3)  Saturn two-dimensional wind velocity and density anomaly profiles    -------------------------------------------------------------------------    TXT_FILENAME = 3_Saturn_wind_velocity_density_anomaly.mat    This file contains Saturn's zonal wind velocity structure and the resulting    density anomaly structure, calculated using thermal wind balance, as a    function of latitude and radius in a longtitudinal section. Each data point    is sampled in polar coordinates. This file includes the following    variables:        - 'theta': A 901-by-71 array of latitude (units of radians),        - 'r': A 901-by-71 array of normalized radius (no units),        - 'u': A 901-by-71 array of zonal wind velocity (units of m/s),        - 'rho': A 901-by-71 array of density anomaly (units of kg/m^3).

=============================================================================ACKNOWLEDGMENTS=============================================================================

The research was carried out at the Jet Propulsion Laboratory, California Institute ofTechnology, under a contract with the National Aeronautics and Space Administration(80NM0018D0004). Funding for this work was provided by NASA’s Cassini DataAnalysis Program (80NM0018F0612). The Cassini gravity data is publicly availablethrough NASA’s Planetary Data System at https://pds-atmospheres.nmsu.edu/data and services/atmospheres data/Cassini/inst-rss.html. The geometrical data forCassini’s orbit is publicly available at https://naif.jpl.nasa.gov/naif/.© 2024. California Institute of Technology. Government sponsorship acknowledged.=============================================================================PRIMARY POINT OF CONTACT=============================================================================

Seho KimJet Propulsion LaboratoryPlanetary Radar and Radio Sciences(818) 354-9254seho.kim@jpl.nasa.gov

=============================================================================ACRONYMS AND ABBREVIATIONS=============================================================================

     ASCII  American Standard Code for Information Interchange     TXT    Text file