10.5880/ICGEM.2014.001 Grombein, Thomas Thomas Grombein 0000-0002-0722-5574 Geodetic Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany Astronomical Institute, University of Bern (AIUB), Bern, Switzerland Seitz, Kurt Kurt Seitz 0000-0003-1414-6994 Geodetic Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany Heck, Bernhard Bernhard Heck Geodetic Institute, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany GFZ Data Services 2014 Gravity forward modeling Spherical harmonic model Topographic gravity field model Rock–Water–Ice (RWI) decomposition Topographic potential Isostatic potential Topographic-isostatic potential Topographic reduction Isostatic reduction Topographic-isostatic reduction Tesseroids ICGEM geodesy EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TOPOGRAPHIC EFFECTS EARTH SCIENCE > SOLID EARTH > GRAVITY/GRAVITATIONAL FIELD Ince, E. Sinem E. Sinem Ince 0000-0002-3393-1392 GFZ German Research Centre for Geosciences, Potsdam, Germany Reißland, Sven Sven Reißland 0000-0001-6293-5336 GFZ German Research Centre for Geosciences, Potsdam, Germany Grombein, Thomas Astronomical Institute, University of Bern (AIUB), Bern, Switzerland Dataset 10.1007/s10712-014-9283-1 https://igppweb.ucsd.edu/~gabi/crust2.html 10.1029/2011JB008916 CC BY 4.0 High-resolution spherical harmonic representation of the Earth's topographic, isostatic, and topographic-isostatic gravitational potential based on a three-layer decomposition of the topography with variable density values and a modified Airy-Heiskanen concept incorporating seismic Moho depths.

Main features:
- Three-layer decomposition of the topography using information of the 5'x5'global topographic database DTM2006.0
- Rigorous separate modeling of rock, water, and ice masses with layer-specific density values (2670, 1000, 920 kg m-3)
- Avoidance of geometry changes compared to classical condensation methods (e.g. rock-equivalent heights)
- Ellipsoidal arrangement of the topography using the GRS80 ellipsoid as reference surface
- Adapted and modified Airy-Heiskanen isostatic concept - Incorporation of seismic Moho depths derived from CRUST2.0
- Location-dependent estimation of the crust-mantle density contrast

Processing:
- Forward modelling in the space domain using tesseroid mass bodies
- Transformation of global gridded values to the frequency domain by applying harmonic analysis up to degree and order 1800

Model versions:
- Spherical harmonic coefficients of the RWI model are provided by three versions
(GM = 3.986004415e+14 m3 s-2, a = 6378136.3 m):
RWI_TOPO_2012 (topographic potential)
RWI_ISOS_2012 (isosatic potential)
RWI_TOIS_2012 (topographic-isostatic potential)

- To allow the evaluation of the RWI model by synthesis software that by default subtracts the coefficients of a normal gravity field, three additional versions are available:
RWI_TOPO_2012_plusGRS80 (topographic potential + GRS80)
RWI_ISOS_2012_plusGRS80 (isosatic potential + GRS80)
RWI_TOIS_2012_plusGRS80 (topogr.-isostatic potential + GRS80)

where the following zonal harmonic coefficients of the GRS80 normal gravity field are added to the coefficients of the RWI model:

C( 0,0) = 0.100000014676351e+01
C( 2,0) = -0.484167032228604e-03
C( 4,0) = 0.790304535833168e-06
C( 6,0) = -0.168725253450154e-08
C( 8,0) = 0.346053594536695e-11
C(10,0) = -0.265006548323563e-14
C(12,0) = -0.410788602320538e-16
C(14,0) = 0.447176931400485e-18
C(16,0) = -0.346362561442980e-20

Note that these coefficients are already rescaled to the above specified parameters GM and a of the RWI model.

Details about the used DTM2006.0 topography model can be found in Pavlis et al. (2012, https://doi.org/10.1029/2011JB008916). Details about the used CRUST2.0 model is available from Laske et al. (2000, https://igppweb.ucsd.edu/~gabi/crust2.html).