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High Resolution Global Bathymetry from Satellite Altimetry, with a detailed view of the Arctic Ocean. Ole B. Andersen, P. Knudsen (DNSC),. ICESAT. Outline. Geoid, Gravity and Bathymetry from Altimetry The DNSC05 global marine gravity field Bathymetry. Outlook. + FB.
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High Resolution Global Bathymetry from Satellite Altimetry, with a detailed view of the Arctic Ocean. Ole B. Andersen, P. Knudsen (DNSC),
ICESAT Outline Geoid, Gravity and Bathymetry from Altimetry The DNSC05 global marine gravity field Bathymetry. Outlook ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 2
+ FB Gravity, Mean Sea Surface and Bathymetry • Using Satellite altimetric sea surface height observations. • h = NREF + ΔN + MDT + Δξ + n • MSS = Geoid + MDT (+ FB) • Bandpassed bathymetry can • be estimated in the 50-200 km • Wavelength as density contrast • Drives gravity changes ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 3
DNSC05 Global Gravity Field • DNSC05 is latest KMS field – DNSC06 is under computation • Focused on Improving polar regions. • Truly global marine gravity field (90°S-90°N)- 2 km resolution grid- Retracking (ERS GM)- Incorporated new ultra-high resolution Geoid model PGM04_2160 Geoid • Incorporated ICESAT. ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 4
GSHSS coastline KMS coastline -> GSHSS Improved Data Coverage Retracked ERS-1 1Hz ORIGINAL ESA 1Hz Un-adjusted geoid heights. ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 5
Improvements (DNSC05 – KMS02) Canadian Basin East Greenland (KMS02 noisy). Problems. Striping is visible In DNSC05 Related to Geoid. Dramatic improvevement in comparison with obs. ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 6
Bathymetry in the Arctic Ocean Existing Bathymetry: IBCAO ETOPO-2, ETOPO-2 GTOPO Using IBCAO as reference Colorscale range from 200 –3000 m depth Russian Shelf Canadian Basin Gakken Rigde Kolbensei Ridge Mohns Ridge ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 7
Bathymetry Prediction Wavelength 30 – 150 km Remove / Restore ETOPO 5 – ETOPO2 (tested) Parker Optimal inversion 2 minute resolution test ROT: 15-20 m elev / mGal 5mGal noise = 100 m Bath Topography=200m / 20 mGal ETOPO 5 DNSC Gravity Improved Bathymetry ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 8
Bathymetry Bandpass filtered Bandpass filtered Bathymetry ETOPO-2 30-150 km. Central Ridge Region Shelf Region (too smooth?) Color scale ranges +/- 200 meters. ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 9
Bathymetry from Satellite Altimetry DNSC05 predicted Bathymetry (bandpassed 30-150 km). Resolves more geophysical detail than ETOPO 5 Stribing/noise visible Need to be solved first. ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 10
Outlook • DNSC05 gravity + MSS was completed by end April 2005. • DNSC-06 gravity/MSS/Bathymetry is currently being computed for EGM-2006 • Resolution: 1 minute by 1 minute (2 km by 2 km) • Gravity + Bathymetry will be availabe with the release of EGM06 through ftp from ftp.spacecenter.dk • Investingting Free Board from Retracked Altimetry. • Investigating a stripe-free reference surface. ESA CNES 15 years of progress in Satellite Altimetry | Venice, Italy – March 2006 | OA | page 11