David Hancock (NASA/WFF, USA); Gary Mitchum (University of South Florida, USA); Richard Ray (NASA/GSFC, USA)

Recent analyses by Watson et al. 2015, called attention to a possible spurious (and apparently piece-wise linear) drift during the first six years of the T/P mission based on comparisons to a global network of tide gauges. In this presentation we show evidence that the drift is an artificial one introduced into the system as an independent correction based on an internal instrument calibration. We report on the efficacy of the TOPEX cal1-mode range bias correction based on our tide gauge comparisons and its subsequent impact on the signature of the global mean sea level rate.