Source/sensor: Source/Sensor:
1. TOPEX/POSEIDON altimeters (10/1992 – 06/2002)
2. Jason Poseidon-2 solid-state altimeter (07/2002 – present)
3. DMSP –F8, 10, 11 Special Sensor Microwave Imager (SSM/I) (10/1992 - 07/1999)
4. QuikSCAT SeaWinds scatterometer (08/1999 – present)
5. Reynolds & Smith Sea Surface Temperature (10/1992 – present)

Coverage: October 11, 1992 – present
Tropical Pacific Ocean –34.5 to 34.5 degrees N 120.5 to 289.5 degrees E

Abstract:
This product contains near-surface current estimates, derived using quasi linear and steady physics. The horizontal velocity is directly estimated from sea surface height, surface vector wind and sea surface temperature, these data being collected from the various data sources listed above (Source/Sensor). The absolute velocity is completed using mean dynamic height relative to 1993-1999, inferred from a multi-variate analysis using hydrographic data, surface drifter velocities and altimetry, with a guess based on both CHAMP geoid and the Levitus '98 climatology (referenced to 1500 dbar) (Rio, M.-H. and F. Hernandez, 2004). The model formulation combines geostrophic, Ekman and Stommel shear dynamics, and a complementary term from the surface buoyancy gradient. [Bonjean & Lagerloef, 2002]

The ocean surface velocity files are in netcdf format which contain “filtered” and “unfiltered” velocity data. The “filtered” data set is best used for description of large scale and low frequency variations of surface flow, while the “unfiltered” data would be useful in meso to short scale studies. Each set of data consists of two variables on a one degree grid: one zonal variable (u), and one meridional variables (v). The “filtered” variables have the letter f appended to the end of each variable name (uf, vf). These variables comprise the total zonal and meridional surface velocity components.

An example of one application for this data is to estimate the surface layer heat budget of the equatorial Pacific, specifically with horizontal heat advection. This is important for monitoring the Earth's climate and possible trends, as well as improving the general understanding of Earth's climate

Data Set Volume: ~1.5 MB per data file

Data Format: netcdf