urn:nasa:pds:grail_gravity_derived:data_shadr:gggrx_1200l_bouguer_sha
1.1
GRAIL Gravity ASCII Spherical Harmonic Model: GRGM1200L_BOUGUER
1.18.0.0
Product_Observational
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_1200l_bouguer_sha.tab
2021-03-16
This file contains coefficients and related data for the GSFC Lunar gravity
field GRGM1200L, a degree and order 1199 Spherical Harmonic Model, derived
from a series of local gravity solutions. This project was funded by NASA
grant NNX15AJ65G.
The Bouguer gravity is obtained by differentiating the gravity disturbances
due to the lunar topography from the gravity disturbances as measured by the
GRGM1200L 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
2550kg/m**3 is assumed. A finite-amplitude correction of the 20th order
is used, following WIECZOREK and PHILLIPS, 1998 (JGR, doi:10.1029/97JE03136).
The maximum degree of this model is 1199, because the grid spacing to do the
spherical harmonic transforms uses 'Lmax+1', and so in order to use a 0.15
degrees by 0.15 degrees grid, we use Lmax=1199. For these Bouguer
coefficients, degree 1 terms are also included.
No uncertainties are included in this table file.
This file is a pair of ASCII tables: a header table and a table of
1439999 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
720599
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_1200l_bouguer_sha.lbl
0
PDS3
Original PDS3 label
Carriage-Return Line-Feed