1. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 1 Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) Graphics files in directories: d:\nico\proj\GOCE\graphics\* d:\nico\proj\GOCE\GranadaIIreport\graphics d:\images\geo Graphics files in directories: d:\nico\proj\GOCE\graphics\* d:\nico\proj\GOCE\GranadaIIreport\graphics d:\images\geo

2. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 2 Issues of Concern Earthquakes & volcanic activities Thermohaline ocean circulation & heat transport Ice Sheet Melting Global unification of height system Sea level change

3. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 3 International Programme International Lithosphere Programme (ILP) Int. Decade of Natural Disaster Reduction (IDNDR) International Association of Geodesy (IAG) World Climate Research Programme (WCRP) - GEWEX - WOCE/CLIVAR - GCOS/GOOS - ACSYS/CLIC International Geosphere/Biosphere Program (IGBP) - LOICZ Intergovernmental Oceanographic Commission (IOC) - GLOSS Earthquakes and Volcanic Activities Global Unification of Height System Thermohaline Ocean Circulation and Transport of Heat. Ice Sheet Melting Sea Level Change

4. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 4 Research Goals Solid Earth Physics anomalous density structure of lithosphere and upper mantle Oceanography determination of dynamic ocean topography Ice Sheets improved knowledge of ice sheet balance Geodesy unified height systems, “levelling by GPS” and from the above improved Sea Level Change Studies

5. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 5 determine the Earth’s gravity field with an accuracy of 1 mgal (1 mgal = 10 -5 m/s 2 ) determine the geoid (= equipotential surface for a hypothetical ocean at rest) with an accuracy of 1 cm achieve this at length scales down to L = 100 km (degree and order 200) Mission Objectives

6. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 6 Presentation Outline Mission Rationale Science & Application Mission Design Performance Conclusions

7. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 7 terrestrial gravity anomalies large unsurveyed areas, heterogeneous data, offsets and biases geoid mapping via satellite altimetry not acceptable for oceanography satellite orbit analysis - only large spatial scales are satisfactory - heterogeneous data - error correlation Mission Rationale Limitations of Existing Gravity Field Data

8. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 8 Mission Rationale Incomplete Data Coverage gravdensBGI.gif

9. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 9 GEOID terrain ALTIMETRY Mission Rationale Limitation with Satellite Altimetry geoid_altim2.ppt

10. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 10 egm.bw.eps Mission Rationale Signal Accuracy versus Spatial Scales

11. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 11 Satellite-to-Satellite Tracking in High-Low Mode SST-hl Satellite-to-Satellite Tracking in Low-Low Mode SST-ll Satellite Gravity Gradiometry SGG Mission Rationale Spaceborne Gravity Field Methods

12. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 12 GPS - satellites Earth mass anomaly 3-D accelerometer Mission Rationale SST - hl sst_hl.eps SST - hl

13. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 13 SST - hl GPS - satellites Earth mass anomaly Mission Rationale Combined SST - ll and SST - hl sst_ll.eps SST - ll

14. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 14 SGG Earth mass anomaly GPS - satellites Mission Rationale Combined SGG and SST - hl gradiometry.eps SST - hl

15. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 15 Orbit as low as possible and near polar Uninterrupted tracking in 3-D Isolation of gravitational signal Amplification of gravitational signal by principle of differentiation Mission Rationale Gravity Field Satellite Design Criteria

16. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 16 Orbit altitude 250 km and sun-synchronous (inc.= 96.5˚) Uninterrupted and 3-D high-low tracking with GPS satellites relative to ground network Drag-free system and elimination of residual drag common mode rejection Gravity signal amplification by gradiometry (differential accelerometry) in addition: all component gradiometer Mission Rationale GOCE versus Design Criteria

17. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 17 Mission Rationale Full Tensor Gradiometer Measurements goce_eqn.jpg gravity gradient angular acceleration angular velocities acceleration differentiation

18. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 18 translational forces angular forces star sensors drag control angular control * * GPS/GLONASS SST -hl GRAVITY GRADIOMETER measures : GRAVITY GRADIENTS angular accelerations common mode accelerations AB Mission Rationale Instrument Concept satellit.ppt

19. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 19 Mission Rationale Uniqueness CGG_fill_bw.eps CGG_plainx.eps CGG_overlayx.eps CGG_fill_bw.eps CGG_plainx.eps CGG_overlayx.eps SGG achieves highest attainable resolution SGG and SST-ll are complementary

20. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 20 Mission Rationale The 3-D structure of the Gravity Field vik.bw.eps

21. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 21 Mission Rationale The 3 -D structure of the Error Coefficient

22. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 22 Mission Rationale The Interdisciplinary Research GIGGOS.doc (.eps) Earth System Model - ocean - ice sheet - lithosphere - mantle - core Solid Earth Physics Geodesy CryosphereOceanography Sea Level Change