Chasing Errors: Attempting to Further Reduce Uncertainty in the Altimeter Climate Record
Event: 2014 Ocean Surface Topography Science Team Meeting
Session: Quantifying Errors and Uncertainties in Altimetry data
Presentation type: Type Oral
The global mean sea level (GMSL) climate record from the TOPEX and Jason altimeters spanning 1993-present required ancillary corrections to the project-produced geophysical data records (GDR) in order to properly account for instrument and geophysical effects on the derived sea surface heights. In this work, we attempt to further reduce the uncertainty in altimeter-era climate data record by updating our GMSL processing to the latest, state-of-the-art corrections, investigating techniques to reduce the impact of the 59-day signal in TOPEX-derived sea surface heights, and looking at the effects on the GMSL of various data editing criteria applied to the altimeter and ancillary data. Updates to the latest, state-of-the-art corrections include: replacing the mean sea surface reference to newer versions and testing their effects on the GMSL time series; smoothing of the GDR ionospheric correction along-track in all missions to reduce noise (this was not done previously in our processing); and testing the substitution of updated orbit solutions from GSFC and other groups. Additionally, we review the effects of updating our processing using the latest versions of the GOT 4.x series of tide models (as well as the FES model) and their effect on reducing the 59-day signal found on TOPEX and Jason-1 sea surface height estimates. Finally, we re-investigate the effect to the GMSL time series of quality-control applied to the altimeter data and on the ancillary corrections.