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Integration of Gravity D ata I nto a Seamless T ransnational H eight M odel for North America. Daniel Roman, Marc Véronneau , David Avalos, Xiaopeng Li, Simon Holmes, and Jianliang Huang Session 5: Paper S5-075. Gravity for the Redefinition of the American Vertical Datum (GRAV-D).
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Integration of Gravity Data Into a Seamless Transnational Height Model for North America Daniel Roman, Marc Véronneau, David Avalos, Xiaopeng Li, Simon Holmes, and JianliangHuang Session 5: Paper S5-075
Gravity for the Redefinition of the American Vertical Datum (GRAV-D) • Overview • Not just aerogravity • Use to clean/salvage two million terrestrial data • Makes improved geoid • Must use satellite data • Yields a vertical datum • Neighboring countries • Must develop a North America Model Gravity Geoid and Height Systems Venice, Italy 09-12 OCT 2012
GRAV-D Status Map Key Green: Available data and metadataBlue: Data being processedOrange: Data collection underwayWhite: Planned for data collection TX09 Gravity Geoid and Height Systems Venice, Italy 09-12 OCT 2012
Discussion of GRAV-D intent • Goal of a cm-level accurate geoid • Must meld different gravity sources • To do this: must resolve systematic errors in gravity observations • Compare aerogravity to satellite data • Constrain aerogravity to GRACE/GOCE • Combined satellite & airborne gravity field model- somewhere between deg 100-250 • Use aerogravity to fix errors and bridge spectral gap with terrestrial surveys • Derive shortest wavelengths from high resolution terrain and density models • Develop a seamless gravity field to 10,800 • Rigorously transform to generate geoid heights and DoV’s satellite models (GRACE/GOCE) airborne gravity Satellite-Airborne Transition Band Variance (m2) Airborne-Terrestrial Transition Band terrestrial gravity ATTB: 150-450 (100-540 with tapers) Gravity Geoid and Height Systems Venice, Italy 09-12 OCT 2012
More clear Systematic features in Historical surface data, focus on long wavelength
More clear short wavelength Systematic features in Historical surface data are detected after adding airborne information
Line 2144 Line 5357 Line 3613 Line 5162
EGM2008 (GRACE Only) EGM2008 (GOCO03S) GOCO03S+Aerogravity
EGM2008 (GRACE Only) EGM2008 (GOCO03S) GOCO03S+Aerogravity
Summary • GOCO03S benefits EGM2008 • Systematic errors in terrestrial data still exist • Such errors lead to systematic geoid errors • Must resolve these for cm-level accuracy • Aerogravity in Texas differs from terrestrial at the 3-5 mGal range • Can be discerned in some terrestrial profiles • Data cleaning will be required to resolve these Gravity Geoid and Height Systems Venice, Italy 09-12 OCT 2012
QUESTIONS? Gravity Geoid and Height Systems Venice, Italy 09-12 OCT 2012