Harmonic topography
Spherical harmonic topography and potential modelling
Researchers of the Western Australian Geodesy Group have developed a suite of spherical harmonic models of Earth’s topography, rock-equivalent topography, Earth’s shape and implied topographic potential. Our Earth2012 and Earth 2014 models are complete to degree and order 2160. The spherical harmonic models available here model topography, water and ice masses based on various data sets and can be used in applications such as forward-modelling, Bouguer anomaly computation and evaluation of geopotential models. The Earth 2012 and Earth 2014 models were used successfully in recent studies on GOCE (Gravity field and Steady-State Ocean Circulation Explorer) gravity fields and Earth’s topographic potential.
The Earth2012 topography models represent Earth’s surface topography in different representations with a resolution of 10 km (degree 2160).
Data
- Earth’s surface (with water): Harmonic model of the interface between Earth and its atmosphere, providing heights above mean sea level of the terrain and ice over land and zero heights over the oceans.
Earth2012.topo_air.SHCto2160.zip (46MB) - Earth’s surface (without water): Harmonic model of the Earth’s topography without ocean water masses. This model provides heights of the terrain and of ice over land and bathymetric depths over the oceans, Caspian Sea and major inland lakes (Superior, Michigan, Huron, Erie, Ontario and Baikal).
Earth2012.topo_bathy.SHCto2160.zip (46MB) - Earth’s surface (without water and ice): Harmonic model of the Earth’s topography without icesheets and without ocean water masses. This model provides heights of the terrain over land, bathymetric depths over the oceans, Caspian Sea and major inland lakes, and bedrock heights over Antarctica and Greenland.
Earth2012.topo_bathy_bed.SHCto2160.zip (46MB) - Earth’s rock-equivalent topography: Harmonic model of Earth’s rock-equivalent topography to degree and order 2160.
Earth2012.RET2012.SHCto2160.zip (46MB) - Earth’s shape (with water): Harmonic shape model of the interface between Earth and its atmosphere, providing radii of the terrain and ice
Earth2012.shape_air.SHCto2160.zip (46MB) - Earth’s shape (without water): Harmonic shape model of the Earth without ocean water masses. This model provides radii of the terrain and ice
Earth2012.shape_bathy.SHCto2160.zip (46MB) - Earth’s shape (without water and ice): Harmonic shape model of the Earth without icesheets and without ocean water masses. This model provides radii of the terrain over land, of the sea bed over the oceans and inland lakes and of bedrock heights over Antarctica and Greenland.
Earth2012.shape_bathy_bed.SHCto2160.zip (46MB) - Earth’s rock-equivalent topography as shape model: Harmonic shape model of Earth’s rock-equivalent topography to degree and order 2160.
Earth2012.shape_RET2012.SHCto2160.zip (46MB)
The Earth 2012 topographic potential models describe Earth’s topographic potential in spherical harmonics and in terms of two different approximation levels (spherical and ellipsoidal approximation).
Data
- Earth’s ellipsoidal topographic potential to d/o 2190 Spherical harmonic gravitational potential coefficients of RET2012 to degree and order 2190 in ellipsoidal approximation
dV_ELL_RET2012_SHCto2190.zip - Earth’s spherical topographic potential to d/o 2160 Spherical harmonic gravitational potential coefficients of RET2012 to degree and order 2160 in spherical approximation
dV_SPH_RET2012_SHCto2160.zip
New Earth 2014 topography and topographic potential models are conceptually similar to Earth 2012, but are based on significantly improved bathymetry and ice mass data sets (e.g., Earth2014 includes Bedmap2 over Antarctica).
More details on the above models and information on the construction and data sources used is available via the linked model pages. The Earth2012 topographic potential model dV_ELL_RET2012 is also available via IAG’s ICGEM gravity model service (http://icgem.gfz-potsdam.de/ICGEM/). The Earth2014 topographic potential model dV_ELL_RET2014 is included in European Space Agency (ESA’s GOCE user toolbox.
Contributors
- Dr Christian Hirt
- Dr Sten Claessens
- Associate Professor Michael Kuhn
- MSc Moritz Rexer