First Assessment of Jason-1 GDR-E Reprocessing over Ocean

Sylvie Labroue (CLS, France)


Sabine Philipps (CLS, France); Michael Ablain (CLS, France); Cécile Renaudie (CLS, France); Pierre Matton (CLS, France); Hélène Roinard (CLS, France); Nicolas Picot (CNES, France); Emilie Bronner (CNES, France)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Regional and Global CAL/VAL for Assembling a Climate Data Record

Presentation type: Type Oral

Jason-1 was launched in December 2001 and routinely monitored the ocean until June 2013, date of its final measurement. It first flew on the historical ground track, as a successor of TOPEX/Poseidon mission. In February 2009, Jason-1 assumed a new orbit midway between its original ground track but with a time lag of approximately 5 days with Jason-2 to provide an optimal coverage for Near Real Time (NRT) applications. In May 2012, it left its repeat track orbit for a geodetic phase until it was finally decommissioned.
Jason-1 time series continued the extraordinary sea level record first initiated by TOPEX/Poseidon mission. Even if this mission is finished, the quality of such a record can still be improved, as science progresses are continuously made.
In 2014, CNES and NASA have started the reprocessing of the new Jason-1 GDR-E release. The main improvements concern the geophysical content of the products which means that all parameters linked to the altimeter remains unchanged. A first assessment is given in this study on the several years available. We will address several issues
- Assessment of the preliminary orbits provided in the products (standard E orbits) which use a new gravity field model that should enhance the regional mean sea level by reducing the basin scale discrepancies
- Assessment of the new radiometer parameters, especially the stability of the wet tropospheric correction which is a key issue for Global Mean Sea Level studies.
- Assessment of the 58.77-day signal due to an error in the ocean tide model previously used in the Jason-1 GDR.
- Cross calibration with TOPEX and with Jason-2 missions during the several months of commissioning phase. This knowledge is important since it allows a seamless transition and reducing the errors between the three time series (TOPEX, Jason-1, Jason-2) and resulting in a 21 year accurate record for the global and regional mean sea level.
- Cross calibration with Jason-2 and Envisat missions which gives insight on the errors of each mission.

Oral presentation show times:

RoomStart DateEnd Date
Ballroom Wed, Oct 29 2014,17:00 Wed, Oct 29 2014,17:15
Sylvie Labroue