urn:nasa:pds:grail_gravity_derived:data_shadr:gggrx_1200a_bouguer_sha 1.2 1.18.0.0 Product_Observational 2023-05-24 1.2 Updated file comment regarding principal axis frame 2023-02-01 1.1 Updated a description in the SHADR Coefficients Table 2022-08-12 1.0 Initial version 2012-03-01Z 2012-12-14Z Gravity Recovery and Interior Laboratory Mission urn:nasa:pds:context:investigation:mission.gravity_recovery_and_interior_laboratory data_to_investigation Gravity Recovery and Interior Laboratory A Host urn:nasa:pds:context:instrument_host:spacecraft.grail-a is_instrument_host Gravity Recovery and Interior Laboratory B Host urn:nasa:pds:context:instrument_host:spacecraft.grail-b is_instrument_host Lunar Gravity Ranging System A for GRAIL-A Instrument urn:nasa:pds:context:instrument:grail-a.lgrs-a is_instrument Lunar Gravity Ranging System B for GRAIL-B Instrument urn:nasa:pds:context:instrument:grail-b.lgrs-b is_instrument Moon Satellite urn:nasa:pds:context:target:satellite.earth.moon data_to_target gggrx_1200a_bouguer_sha.tab 2016-03-01 This file contains coefficients and related data for the GSFC Lunar gravity field GRGM1200A, a degree and order 1200 Spherical Harmonic Model. It is a preliminary GSFC gravity field that includes the entire GRAIL data set (and that does not include other data). The Bouguer gravity is obtained by differentiating the gravity disturbances due to the lunar topography from the gravity disturbances as measured by the GRGM900C gravity model. The lunar shape is obtained from the laser altimetry data acquired by the Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO), which are available on the NASA PDS Geosciences node. A uniform crustal density of 2500kg/m**3 is assumed. A finite-amplitude correction of the 9th order is used, following WIECZOREK and PHILLIPS, 1998 (JGR, doi:10.1029/97JE03136). No uncertainties are included in this table file. In addition to the errors of the GRGM1200A gravity field coefficients, small but uncharacterized errors in the topographic coefficients (e.g., due to uneven LOLA sampling) would apply. Some details describing this model are: The spherical harmonic coefficients are fully normalized (geodesy 4pi normalized). The uncertainties are calibrated (the formal uncertainties multiplied by a factor of 1.635). The reference radius = 1738.0 km The gravitational parameter is GM = 4902.80011526323 km**3/s**2 The planetary ephemeris is de430 and defines the lunar body-fixed coordinate system in the principal axes frame. A Kaula type power law constraint is applied to the spherical harmonics coefficients for degrees greater than 600 (3.6e-4/n^2). The weighting of the KBRR data is: 0.03 microns/sec in the primary mission 0.05 microns/sec in the extended mission The weighting of the DSN data is: 0.12mm/s in both the primary and extended mission The nominal tidal Love number is k2 = 0.024133 +/- 0.000010 The current best reference for the GRGM1200A gravity field is LEMOINEETAL2014, published in the Geophysical Research Letters with the DOI number 10.1002/2014GL060027 . For additional details on the GRAIL mission, data and methods, see LEMOINEETAL2013. As with other lunar gravity fields, the map is expressed in the Moon Principal Axes frame, which slightly differs from the Moon Mean Earth frame. For comparison with lunar topography, users are advised to make use of the LOLA PDS products also archived in the Moon Principal Axes frame, such as the LDEM_64_PA and LRO_LTM01_PA_1080_SHA.TAB products in the LRO-L-LOLA-4-GDR-V1.0 dataset, which can be accessed at the PDS Geosciences Node or at the LOLA PDS Data node. Note also that the reference radius for gravity (1738 km) and topography (1737.4 km) are different. This file is a pair of ASCII tables: a header table and a table of 1442397 coefficients. Definitions of the tables follow. 0 1 The SHADR header includes descriptive information about the spherical harmonic coefficients which follow in SHADR_COEFFICIENTS_TABLE. The header consists of a single record of eight (delimited) data columns requiring 137 bytes, a pad of 105 unspecified ASCII characters, an ASCII carriage-return, and an ASCII line-feed. Carriage-Return Line-Feed 9 0 244 Reference_Raduis 1 1 ASCII_Real 23 Km The assumed reference radius of the spherical planet. Constant 2 25 ASCII_Real 23 For a gravity field model the assumed gravitational constant GM in kilometers cubed per seconds squared for the planet. For a topography model, set to 1. Uncertainty_in_Constant 3 49 ASCII_Real 23 For a gravity field model the uncertainty in the gravitational constant GM in kilometers cubed per seconds squared for the planet. For a topography model, set to 1. Degree_of_Field 4 73 ASCII_Integer 5 The degree of model field. Order_of_Field 5 79 ASCII_Integer 5 The order of the model field. Normalization_State 6 85 ASCII_Integer 5 The normalization indicator. For gravity field: 0 coefficients are unnormalized 1 coefficients are normalized 2 other. Reference_Longitude 7 91 ASCII_Real 23 Degree The reference longitude for the spherical harmonic expansion; normally 0. Reference_Latitude 8 115 ASCII_Real 23 Degree The reference latitude for the spherical harmonic expansion; normally 0. Fill 9 138 ASCII_String 105 SHADR Coefficients Table 244 721800 The SHADR coefficients table contains the coefficients for the Spherical Harmonic Model. Each row in the table contains the degree index m, the order index n, the coefficients Cmn and Smn, and the uncertainties in Cmn and Smn. The (delimited) data require 107 ASCII characters; these are followed by a pad of 13 unspecified ASCII characters, an ASCII carriage- return, and an ASCII line-feed. Carriage-Return Line-Feed 7 0 122 COEFFICIENT DEGREE 1 1 ASCII_Integer 5 The degree index m of the C and S coefficients in this record. COEFFICIENT ORDER 2 7 ASCII_Integer 5 The order index n of the C and S coefficients in this record. C 3 13 ASCII_Real 23 The coefficient Cmn for this spherical harmonic model. S 4 37 ASCII_Real 23 The coefficient Smn for this spherical harmonic model. C_Uncertainty 5 61 ASCII_Real 23 The uncertainty in the coefficient Cmn for this Spherical Harmonic Model. S_Uncertainty 6 85 ASCII_Real 23 The uncertainty in the coefficient Smn for this Spherical Harmonic Model. Fill 7 108 ASCII_String 13 A pad of 13 unspecified ASCII characters. gggrx_1200a_bouguer_sha.lbl 0 PDS3 Original PDS3 label Carriage-Return Line-Feed