Calibrating the jason-1 measurement system: Initial initial results from the corsica and harvest verification experiments

We present calibration results from Jason-1 (2002-) and TOPEX/Poseidon (1992-) overflights of dedicated verification sites on the Mediterranean island of Corsica and on a California offshore oil platform (Harvest). Harvest served for a decade (1992–2002) as a calibration site for the TOPEX/Poseidon (T/P) mission, and is serving in a similar capacity for Jason-1. Initiated in 1996, the Corsica experiment features a fiducial reference station near Aspretto, and a primary sub-satellite tide-gauge deployment site 40 km south at Cape Senetosa. Both Corsica and Harvest feature carefully designed collocations of space-geodetic and tide-gauge systems to support the absolute calibration of the altimetric sea-surface height (SSH). Early estimates of the SSH bias from Harvest and Corsica are in excellent agreement, indicating that interim SSH measurements from Jason-1 were too high by +5 ± 1 cm (one standard error). By incorporating improved estimates of the Jason-1 sea-state bias and columnar atmospheric wet path delay, we observe a significant increase—to about 12 cm—in the SSH. Excepting the bias, the high accuracy of the Jason-1 measurements is in evidence from early overflights. In addition to providing important insight on the accuracy of the science data products during the validation phase of the mission, the estimates of the SSH bias and stability from Corsica, Harvest and other calibration programs will be used to link the T/P and Jason-1 sea-level records.