Content Summary | This work presents the latest absolute and relative calibrations for the altimeters of the Sentinel-3A and Jason-3 at the Permanent Facility for Altimeter Calibration in west Crete, Greece. Results have been determined at first with the transponder at the CDN1 Cal/Val site on the mountains of west Crete using the ascending Sentinel-3A Pass No. 14 and the descending Jason-3 Pass No.18. Then, sea-surface calibration has been carried out with the descending Sentinel-3A Pass No. 335 and the ascending Jason-3 Pass No.109 based on the Cal/Val facility on Gavdos island. For Sentinel-3A results have been established for cycles 3–27 using Level 2 (Level 0 for transponder) and Non-Time Critical data. For Jason-3, cycles 5–80 and the S-GDR-D data have been worked with the transponder calibration, while for the results with sea-surface calibration, cycles 1–80 with the I-GDR-D data have been implemented.
Sentinel-3A produces biases of the order of a few mm either with the transponder (+2.7 mm) or with the sea-surface calibration (7.3 mm and −4.4 mm). The altimeter of Jason-3 presents a range bias at +22.7 mm (No.18) with the transponder and −36.7 mm for the bias in sea-surface height, respectively. Finally, comparison of sea-surface heights observed by Sentinel-3A relative to Jason-3 demonstrates a difference of +4 cm within a period of ±3 days about 20 km south of Gavdos. | en |
Bibliographic Citation | S. P. Mertikas, C. Donlon, P. Femenias, C. Mavrocordatos, D. Galanakis, T. Guinle, F. Boy, A. Tripolitsiotis, X. Frantzis, I. N. Tziavos, and G. S. Vergos, “Absolute calibration of Sentinel-3A and Jason-3 altimeters with sea-surface and transponder techniques in west Crete, Greece,” in Fiducial Reference Measurements for Altimetry, vol 150, International Association of Geodesy Symposia, S. Mertikas, R. Pail, Eds., Cham, Switzerland: Springer Nature, 2020, pp. 41–47, doi: 10.1007/1345_2019_63. | en |