Using Kolmogorov-Smirnov Statistics to Compare Geostrophic Velocities Measured by the Jason, TOPEX, and Poseidon Altimeters

Abstract

The Kolmogorov-Smirnov (K-S) test is used to compare probability density functions (PDFs) of geostrophic velocities measured by the TOPEX, Poseidon, and Jason altimeters. Velocity PDFs are computed in 2.5° by 2.5° boxes for regions equatorward of 60° latitude. Although velocities measured by the TOPEX and Jason altimeters can differ, on the basis of the K-S test the velocities are statistically equivalent during the ∼200 day period when the satellites followed the same orbit. Full records from TOPEX, Poseidon, and Jason show less agreement, which can be attributed to temporal variability in ocean surface velocities and differing levels of measurement noise.

Keywords:

• Altimetry
• Kolmogorov-Smirnov statistics
• probability density functions
• TOPEX/Poseidon and Jason

Acknowledgments

TOPEX/Poseidon Merged Geophysical Data Records and Jason Geophysical Data Records were provided by the Jet Propulsion Laboratory's Physical Oceanography Data Active Archive Center (http://podaac.jpl.nasa.gov). Funding for this study was provided by the National Aeronautics and Space Administration through the Jason Science Working Team, JPL contract 1224031.

Notes

¹For TOPEX and Jason, the ionospheric correction is smoothed over 150 km. For Poseidon, the equivalent correction is not available, because the instrument is single frequency, and the DORIS correction is used instead.