Rock-Water-Ice topographic gravity field model 2015 (RWI 2015 model)

High-resolution spherical harmonic representation of the Earth's topographic gravitational potential based on a three-layer decomposition of the topography with variable density values. Main features: - Three-layer decomposition of the topography using information of the new 1'x1' Earth2014 topography model - Rigorous separate modeling of rock, water, and ice masses with layer-specific density values: Rock: 2670 kg m-3, Water: 1030 kg m-3 (Ocean), 1000 kg m-3 (Inland), Ice: 917 kg m-3 - Ellipsoidal arrangement of the topography using the GRS80 ellipsoid + geoid undulations as height reference surface - Additional compilation of a consistent rock-equivalent version REQ_TOPO_2015 using condensed DTM-heights 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 2190 Model versions: - Spherical harmonic coefficients of the RWI model are provided by two versions (GM = 3.986004415e+14 m3 s-2, a = 6378136.3 m): RWI_TOPO_2015 (topographic potential) REQ_TOPO_2015 (topogr. potential of rock-equivalent heights) - To allow the evaluation of the RWI model by synthesis software that by default subtracts the coefficients of a normal gravity field, two additional versions are available: RWI_TOPO_2015_plusGRS80 (RWI_TOPO_2015 + GRS80) REQ_TOPO_2015_plusGRS80 (REQ_TOPO_2015 + 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 Earth2014 topography model can be found in Hirt and Rexer (2015, https://doi.org/10.1016/j.jag.2015.03.001).