Coastal sea level in norway from cryosat-2 sar altimetry

Ole Baltazar Andersen (DTU Space, Denmark)

CoAuthors

Martina Idzanovic (NMBU, Norway); Ophaug Vegard (NMBU, Norway)

Event: 2016 SAR Altimetry Workshop

Session: SAR mode performances: SAR CALVAL from Cryosat-2 and Sentinel-3

Presentation type: Type Poster

Conventional altimeters determine the sea surface height with an accuracy of a few centimeters over the open ocean. Although satellite altimetry is a mature discipline,
altimeter observations collected over coastal regions suffer from numerous effects which degrade their quality.
The Norwegian coast adds further complications, due to many islands, mountains, and deep, narrow fjords. The European Space Agency (ESA) CryoSat-2 satellite carries
a Synthetic aperture Interferometric Radar ALtimeter (SIRAL). Due to the SIRAL instrument, CryoSat-2 is able to observe closer to the coast than conventional altimeters.
This motivates the current paper, in which we investigate the potential of CryoSat-2 data to provide improved observations in the Norwegian coastal zone. We make use of CryoSat-2 SARIn mode observations and determine sea surface heights at 23 tide gauges along the coast, and compare these with independent sea-level observations. Using standard CryoSat-2 geophysical (tide + IB) corrections gives a standard deviation of differences of 10-15 cm with respect to tide-gauge observations. Replacing standard corrections with refined corrections using tide-gauge information suggests an improvement of 5 cm.
A special case study at the Stavanger tide-gauge shows a clear improvement of 3 cm when comparing CryoSat-2 vs conventional altimeter data from Jason and SARAL with respect to the tide-gauge observations.
These improved comparison with tide gauge have been achieved even though data from multiple tracks of Cryosat-2 have been used for the comparison (this increase the error in principle) and highlight a great development and improvement with SAR altimetry.
 

Poster show times:

RoomStart DateEnd Date
Grande Halle Mon, Oct 31 2016,18:30 Mon, Oct 31 2016,19:30
Ole Baltazar Andersen
DTU Space
Denmark
oa@space.dtu.dk