Zheng Qu (Raytheon, USA); Richard Ray (NASA/Goddard Space Flight Center, USA); Joshua Willis (Jet Propulsion Lab, USA); Brian Beckley (SGT at NASA / Goddard Space Flight Center, USA)

Under NASA’s “Making Earth System Data Records for Use in Research Environments” (MEaSUREs) program we carried out improvements to altimetry data, such as orbits, sea state bias, etc, in a collaboration between the Jet Propulsion Laboratory, Goddard Space Flight Center, U. South Florida, U. Colorado and U. New Hampshire. As part of this activity, we have generated a new set of altimetric grids, on a 1/6 degree, 5 day sampling, using 2 concurrent satellites, which we reported on in previous years. We reported before on quality tests based on withheld altimetry data. Here we report independent quality tests performed by co-investigator Richard Ray against a standard set of 60 tide gages. We find the RMS difference from the tide gages (for the version JPL1603 of the gridded data) to be 3.1cm, while the RMS over all the tide gage time series is 7.8 cm (signal to noise ratio 6.4). The comparison of the latest AVISO grids to the same tidegage dataset yields an RMS difference of 2.5 cm. A spectral comparison to Jason-3 data, not used in the gridding, is included in this presentation.