Lake Surface Height Calibration of Jason-1 and Jason-2 Over the Great Lakes

Abstract

This study presents results of Jason-1 (J1) and Jason-2 (J2) radar altimetry absolute calibration (cal/val) over the Marblehead lake water level gauge, with an aid of a GPS buoy, in Lake Erie, the Great Lakes, in North America. The altimeter bias is estimated using the height difference between the altimeter lake surface height and the in situ data in each altimeter 10-day repeat cycle. The altimeter bias estimates for J1 are 81 ± 2 and 70 ± 2 mm for Geophysical Data Record (GDR) Versions ‘B’ and ‘C’, respectively, and 148 ± 5 mm (GDR) and 147 ± 7 mm (IGDR) for J2, respectively. The bias estimates are slightly smaller compared with estimates at other dedicated calibration sites such as the Harvest Platform, the Corsica Site, and the Bass Strait site due in part to the effect of the sea state bias. The J2-to-J1 relative bias determined in the tandem mode over Lake Erie is 84 ± 28 mm, which agrees well with the results from the global analysis and the dedicated sites aforementioned.

Keywords:

• Absolute altimeter calibration
• Jason-1
• Jason-2
• GPS buoy
• Great Lakes

Acknowledgements

We thank two anonymous reviewers for their constructive comments, which improved this paper. This study is partially supported by the grants from the National Science Council of Taiwan (NSC 97-2116-M-194-007; NSC 98-2116-M-194-008). The Ohio State University component of this study is funded by NASA's Ocean Science Topography Mission program with subcontracts from JPL (JPL No. 1356532) and the University of Colorado (No. 154-5322), and by the Climate, Water, and Carbon Program at the Ohio State University. We thank Dr. Gerald Mader at National Geodetic Survey for providing his software system (KARS) for processing of the GPS buoy data.