The subsequent data set consists of three years of geostrophic surface velocity anomalies derived from satellite altimetry. The satellite altimetry data was downloaded from the RADS data base (http://rads.tudelft.nl). The applied corrections are addressed in the data files itself.
What makes it unique compared to other geostrophic surface velocity data sets is, that: The geostrophic surface velocity anomalies discussed here, were calculated without applying any spatial or temporal interpolation and without the necessity to assume an isotropic ocean flow field.
Geostrophic surface velocity anomalies in zonal (u) and meridional (v) direction are computed from the Jason-1 - TOPEX/Poseidon (JTP) tandem mission data as was described in detail by Scharffenberg and Stammer [2010, chap. 2], Scharffenberg and Stammer [2011, chap. 2] and Brath et al., [2010, chap. 2] for the complete duration of the JTP tandem mission (09/2002 - 09/2005). As discussed there in great detail, velocity anomaly estimates for u and v are available from this approach every 6.2 km along a virtual center track as anomalies relative to the 3-year mean. The velocity anomalies can be derived as follows: Using two orthogonal SSH gradients, each aligned at a 45° angle to the cross-track direction, two orthogonal geostrophic velocity anomalies (˜u, ˜v ) can be calculated. Owing to the curvature of the track which changes as function of latitude, the distances over which both SSH gradients are calculated differ slightly for each position. A rotation of this set of velocity components (˜u, ˜v) finally yields a velocity vector of the velocity anomalies (u, v) in a Cartesian reference frame with zonal and meridional orientation on the interleaving (virtual velocity) track between the T/P and Jason-1 tracks. The method had been first devised by Stammer and Dieterich , estimates of uncertainties where given by Leeuwenburgh and Stammer  and velocity errors emerging from JTP data are shown in the work of Scharffenberg and Stammer [2010, Figure 3].
The data set consists of two products:
1) Original resolution. Along track velocity anomaly estimates on the interleaving velocity track. The fields are provided for each 9.91 day repeat cycle (109) with variables sorted in ARCS (254) and measurements on each ARC (3127) (this product is not visualized on the LAS server)
2) Gridded product from the along track data. The fields are provided as 2°x 1° gridded fields for each 9.91 day repeat cycle (109).