California Cal/Val

What is the role of finescale processes in connecting the surface of the ocean and its interior?

The California Xover will be adopted by the mission Calibration and Validation (Cal/Val) team. The main purpose of the campaign is to provide the ground truth of the sea surface height at small scales (< ~ 100km) for the Cal/Val of the mission science requirement specified in wavenumber space. The ground truth should be free, as much as possible, of the noise and errors in satellite measurements. The steric-height approach has been adopted in the methodology, which involves observing temperature and salinity in the ocean interior to derive the steric height.

The campaign includes 11 CTD moorings placed along a Sentinel-3A ground track, which is near the centre of a SWOT swath. 4 of the 11 moorings are deep-reaching to capture the deep high-frequency internal gravity wave signals. 7 moorings will focus on the upper 500m to capture the small-scale surface intensified eddies. By combining the 11 moorings, we will be able to reconstruct the synoptic SSH field covering 20 – 100 km wavelengths for validating SWOT SSH at these scales. There will be at least two gliders sampling in the cross-swath direction. They will provide additional cross-swath information, as well as a means for risk reduction of any potential mooring malfunction. A barometer will be placed in the centre mooring to measure atmospheric pressure.

The data gathered during the Cal/Val campaign will be important to close the SSH budget and will shed light on the connections between the surface of the ocean and its interior.

In addition, the instrumentation will enable studies of small-scale ocean dynamics, such as the interaction between eddies and internal gravity waves and how to disentangle them from the SWOT measurements, and the vertical heat flux associated with small-scale eddies and eddy-wave interactions.

Principal investigators: Uwe Send, Drew Lucas, Matthias Lankhorst, Amy Waterhouse (SIO/UCSD); Scott Stalin (PMEL/NOAA); Oscar Schofield (Rutgers Univ.); Tom Farrar, Magdalena Andres (WHOI); Lee-Lueng Fu, Bruce Haines (JPL/Caltech), Jinbo Wang (JPL/NASA).

Contact point for the study site: Jinbo Wang (