Riccardo Riva (Delft University of Technology, Netherlands)

Time series of regional sea level budgets provide a better understanding of the causes for sea
level variations as well as a better understanding of the errors of the measurement systems
involved. This study therefore aims at closing the budgets in the North-Atlantic of 10x10
degree boxes using the Jason satellites, GRACE and the ARGO float network. Time series
for altimetry are created using along-track data from the RADS database. A new averaging
method is applied to altimetry data to overcome problems with conventional gridding (a
large ground-track seperation at the Equator) and the latitude weighting (underweighting
at high latitudes). Additionally, geographical dependencies of the intermission biases are
considered. Using the full covariance matrices provided by CSR, GRACE solutions are sta-
tistically filtered to minimize hydrological leakage and reduce striping. The ARGO data
are statistically interpolated to a grid with full variance-covariance matrices. For all three
systems, the errors are propagated to provide time series of monthly averages over the con-
sidered region including formal error bars. We are able to close the budgets for most of the
10x10 degree boxes in the North-Atlantic.