Abstract's details

Retracked TOPEX Climate Data Record

Philip Callahan (Jet Propulsion Laboratory, United States)


Joseph McMichael (Jet Propulsion Laboratory, United States); Brent Williams (Jet Propulsion Laboratory, United States); Doug Vandemark (University of New Hampshire, Institute for the Study of Earth, Oceans, Space, United States); Hui Feng (University of New Hampshire, Institute for the Study of Earth, Oceans, Space, United States)

Event: 2015 Ocean Surface Topography Science Team Meeting

Session: Instrument Processing: Measurement and retracking (SAR and LRM)

Presentation type: Type Oral

Contribution: PDF file


We will report on delivering the TOPEX Climate Data Record product. The main effort for this product is retracking the data to account for waveform leakages and point target response (PTR) changes, and it also includes updating other components of the record to be compatible with Jason GDRs.

It was previously determined that leakages limited the use of the Cal-1 data for determining PTRs to the first seven lobes. Methods to extend the PTR to the necessary 30 lobes to reach full accuracy were implemented. It was also determined that it was not feasible to improve upon the original WFF waveform weights. The resulting PTRs and the original waveform weights were used to retrack all of the TOPEX data in three modes: fixed skewness of 0 and 0.1 and solving for skewness. Previously only the solve-skewness mode has been extensively evaluated. The fixed skewness of 0.1 is of particular interest as that is what is done for Jason.

The retracked data with GSFC orbits std1410, updated tides from GOT4.10c, and fully corrected sigma0s were used to solve for new sea state bias models for Alt-A and Alt-B.

During the process of updating the data, we became aware of a difference between the original GDRs and the MGDR-B from PODAAC that is widely used. The latter includes the WFF range calibration correction. The properties of this correction were investigated.

Results from the final TOPEX Climate Data Record product delivered to NOAA will be presented.

The work reported here was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration with funding from the NOAA Climate Data Records program.

Oral presentation show times:

Room Start Date End Date
Grand Ballroom 1 Tue, Oct 20 2015,16:15 Tue, Oct 20 2015,16:27
Philip Callahan
Jet Propulsion Laboratory
United States