Towards a Roadmap for Future Satellite Gravity Missions September 30 - October 2, 2009, Graz, Austria

Breakout Session B3 (Wednesday, September 30, 2009): Data Processing, Modeling & Interpretation
Co-Chairs: Srinivas Bettadpur, Frank Flechtner.
Rapporteur: nn.
Session description:

This session focuses on anticipated challenges in the improved analysis and use of data from future satellite gravity missions. The context includes use of data from GRACE-like low-low satellite tracking (LL-SST) missions; GOCE-like satellite gravity gradiometer (SGG) missions; Low-Earth orbiters (LEO) using GNSS, satellite laser ranging (SLR) or radiometric (DORIS) tracking from ground or space; and any combinations thereof. Within this context, we focus on three important topics:

Useability: For a diverse variety of users, as evidenced by the work of the existing satellite gravity community, how can we make the satellite gravity measurements as well as data products more useable? For example, specific questions include:

• What ancillary satellite data is necessary for Level-1 and Level-2 analysis & interpretation?
• Role of “ground-truth” or a priori knowledge of the structure of the process being observed – What information is necessary for Level-1 and Level-2 analysis? And is it available in a simple-to-use form?
• Enforcing mutual consistency in the combination of multi-technique products – e.g. GOCE+GRACE; or degree-1 harmonics; or GRACE+SLR; etc.

De-Aliasing: This refers to the use of a priori gravity field models to remove the contributions to the measurements from short-period geophysical variability, before estimates of the lower-frequency variability are extracted. Interesting questions include:

• To what extent do we have to improve the background models for future gravity missions?
• Is it necessary to improve these independently from the gravity missions? Or can we simultaneously solve for some components of the background models?
• Can we use assimilation/modeling methods to eliminate the need for de-aliasing?

Algorithms: Analyses of the data from the ongoing satellite gravity missions are helping us identify deficiencies in the conventional satellite geodetic methods. What are the future directions for algorithmic improvements? Topics include numerical, computational, parameterization, and modeling aspects of the satellite geodetic methodology.