5. The next 3 figures are from the Ocean Pathfinder Project at NASA/GSFC
The next 3 figures are from the Ocean Pathfinder Project at NASA/GSFC. Compliments of B. Beckley and R. Ray.

8. Jason – T/P Mean SSH
Effect of precision orbits in mean sea level determination
GDR based orbits
GSFC replacement orbits
Improved agreement seen in lower left image results from improved TOPEX and Jason-1 orbits. Improvement was realized by using the more current ITRF2000 reference frame and associated station complement in the orbit computations, the GGM02C gravity field, and other improved force and measurement models.
Provided by R. Ray and B. Beckley.

9. Trend in T/P Radial Orbit Differences
New GSFC orbits – MGDR_B JGM3 orbits
Provided by R. Ray and B. Beckley

10. Impact of Upgraded T/P Precision Orbits on Regional MSL Rates
Provided by R. Ray and B. Beckley

12. Draft recommendations
Extend high precision altimetry beyond Jason-2. The best solution is to continue in the T/P groundtrack, which has proven to provide high quality sea level change estimates. If this must be changed, a priori studies of accuracy and precision must be made. A sun-synchronous or a non-repeating orbit will not meet the requirements for climate studies.
Continued maintenance and enhancement of the global tide gauge network is essential. These data provide the historical context for analyses from altimetry and are also essential to the altimeter calibration problem. Improving spatial distribution is critical.
Address the land motion problem at the tide gauges. Direct geodetic measurements at each site are required. In addition, the larger issue of placing all of these measurements into a consistent, high quality global reference frame is important.
Continued study of the best offsets between different altimetric missions (e.g., TOPEX Side A to Side B and TOPEX to Jason-1) is needed.
Continued study of the acceleration of sea level change over the past century should be done. At present there is good consensus on the 20th century rate and its error bar, but results on acceleration are conflicting.