PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT NOTE = "Description of GRGM1200L GEOTIFF extras files." PUBLICATION_DATE = 2021-03-23 END_OBJECT = TEXT END The following files are an addition in the GEOTIFF subdirectory. They belong to the lunar gravity field model GRGM1200L, which is a model based on 14 separate local solutions patched together. A description of this model can be found in the SHADR directory, in the file gggrx_1200l_sha.lbl, and in GOOSSENSETAL2021. The specific contents of the additional files are described below. All files used a cylindrical projection to generate the GEOTiff files. The coordinates span from -180.0 to 180.0 in longitude and -90.0 to 90.0 in latitude. Because of interpolation issues when going from a gridline registered (which is what the original GMT grids are in this case) to a pixel registered grid, the files here are at a higher resolution than the original model. The original local model GMT grid file (a NetCDF file) can be found GSFC's Planetary Geodynamics Data Archive website, https://pgda.gsfc.nasa.gov/products/80. Resampling from gridline to pixel registration was done with the nearest neighbor mode. gggrx_1200l_anom_l1199.tif: A map of free-air gravity anomalies, at a resolution of 0.075 degrees by 0.075 degrees. The values are in mGal (1 mGal = 0.00001 m/s^2). The size of the map is 4800 by 2400. Note: free-air anomalies are computed as -dT/dr -2T/r, with T the disturbing potential and r the radius, which means that they have a factor of (n-1) in their spherical harmonics expansion, with n the spherical harmonics degree. gggrx_1200l_boug_l660.tif: A map of Bouguer disturbances, at 0.075 by 0.075 degrees. This map was generated from a spherical harmonics expansion where the contribution of topography is subtracted from free-air gravity. The topography contribution is computed following WIECZOREK&PHILLI1998, raising topography to the 20th power and using a constant crustal density of 2550 kg/m^3. This map is expanded between spherical harmonics degrees 6 and 660. The values are also in mGal. We exclude the lower degrees to account for the lunar dichotomy effects, and for effects from South Pole-Aitken. The size of this map is 4800 by 2400. Bouguer disturbances are computed as -dT/dr, and have a factor of (n+1) in their spherical harmonics expansion. gggrx_1200l_boug_l900.tif: A map of Bouguer disturbances, at 0.075 by 0.075 degrees. This map was generated in the same way as the map above, except the spherical harmonics degree range is from 6 to 900 for this map. The size of this map is also 4800 by 2400.