Minimize Motivation

Data from the ESA GOCE mission are of fundamental importance to the oceanographic community. It is expected that in conjunction with altimetric observations, gravity data from the ESA GOCE Mission will - for the first time in history - allow access to the absolute ocean dynamic surface topography and to compute the absolute ocean surface geostrophic currents at spatial scales down to about 100 km.

At the moment, only the variable part of the sea level, and thus the geostrophic currents, can be inferred from altimetric heights with sufficient accuracy. Despite their importance for oceanographic studies, the processing and analysis of gravity mission data has proven to be complicated to the point that the lack of proper processing software is hampering progress in the use of those data.

Success in the exploitation of GOCE data therefore seems to depend fundamentally on the proper knowledge of several steps of the detailed gravity data processing procedure in terms of spherical harmonics, their implicit consistent normalization factors, filtering and error data, among others.

However, no ocean circulation products are planned to be delivered as level-2 products as part of the GOCE project so that a strong need exists, for oceanographers, to further process the GOCE level-2 geoid and merge it with Radar Altimetry.

Hence, to facilitate the easy use of GOCE products for oceanographers and to support the needs of specific applications, the development of a user toolbox GUT was identified as an urgent step at the Second International GOCE User Workshop.

Such a toolbox is required to guarantee optimal use of the existing and future gravity data acquired from GRACE and GOCE. In particular, it was recognized and accepted that software packages are required to allow the gravity field data, in conjunction and consistent with any other auxiliary data sets, to be pre-processed by users not intimately familiar with gravity field processing procedure, for oceanographic and hydrologic application, regionally and globally.

From previous work, a preliminary idea about the scope of a GUT toolbox existed already in the community, especially from experience gained through GRACE data processing.

The GOCINA project is another source of valuable information about needs and solutions, that have been consulted while defining GOCE user needs and toolboxes.