As a result of this wide-ranging discussion, the last part of the meeting was devoted to seeing if a consensus existed for recommendations to the various space agencies and science teams. Many issues were left unresolved for the Teams to consider.
In particular, the science teams must work through the relative merits of global scale versus regional calibration exercises. For the latter, the trade-offs between quiet and active sites, be they land or ocean must be better understood. GRACE and related science will need an improved understanding of the accuracies of the operational meteorological products, both pressure and winds. Cooperation of the meteorological centers will be required to do this.
De-aliasing of GRACE (and the altimetric missions) will definitely be required, spanning the entire range of motions from hours to the overall Nyquist period, and including tides (both atmospheric and oceanic), oceanic barotropic motions, and a full range of atmospheric phenomena. Oceanic barotropic models appear to have considerable skill for this purpose, but much more testing will be required.
A mechanism needs to be found for coordinating the groups which are interested in making direct in situ measurements of pressure and velocity in conjunction with GRACE and a more efficient means of communication between the US and European science teams is necessary. The meeting was followed immediately by a joint meeting of the US and European Science Working Teams for GRACE, held at the Society for Chemical Industry, London, 16-17 April. This group began the process of responding to the discussions reported here.