Observing the Ocean Surface Topography at High Resolution by the Surface Water and Ocean Topography (SWOT) Mission

Lee-Lueng Fu (JPL - CalTech, United States)

CoAuthors

Rosemary Morrow (LEGOS/OMP CNRS/CNES/IRD/University Toulouse, France)

Event: 2019 Ocean Surface Topography Science Team Meeting

Session: The Future of Altimetry

Presentation type: Type Oral

This paper presents the oceanographic objectives and plans of calibration and validation, science investigations and applications for the Surface Water and Ocean Topography (SWOT) Mission. This international mission, planned for launch in 2021, will make high-resolution observations of the ocean surface topography as a next-generation altimetry mission utilizing the technique of radar interferometry. With measurement over a swath of 120 km (20 km nadir gap), SWOT will map the entire earth within +/- 77.6 degree latitudes every 21 days. Over the ocean, this new measurement will extend the two-dimensional resolution of ocean surface topography estimated from conventional radar altimetry from 150 km wavelength to possibly 15 km, offering opportunities to study the oceanic dynamic processes at these scales that act as one of the main gateways connecting the interior of the ocean to the upper layer. SWOT has a non-sun-synchronous orbit, specifically designed to observe and improve our understanding of the barotropic and baroclinic tides. As such, it will provide a unique opportunity to observe both low-frequency geostrophically balanced motions and high-frequency internal tides and gravity waves, and their non-linear interactions. We will present an overview of the SWOT Science Team’s work in understanding these dynamical surface topography signals, from high-resolution and high-frequency modeling, and from in-situ and satellite observations.


The first 90 days of the mission (after the commissioning phase for engineering check-out and adjustment) will be flown in a 1-day repeat fast-sampling phase for calibration and validation. This unique, rapid temporal sampling will allow enhanced understanding of the SSH measurement at 15-150 km wavelengths in terms of signals and measurement errors. In particular, there will be two measurements a day at the crossover diamond-shaped regions, where the two-dimensional measurement at twice daily interval will provide the maximum amount of information on rapidly changing signals and errors. We are engaging the international community to participate in in-situ observations under the 1-day orbit swaths, to evaluate and link the SWOT sea surface height measurements to the observed internal oceanic processes in different regions and seasons.

The mission’s science team will be renewed in 2020. The topics of oceanographic investigations cover mesoscale and submesoscale processes; modeling and data assimilation; tides, waves, and high-frequency processes; calibration and validation; coastal and estuarine processes. We will present some of the innovative techniques being developed to reduce the effects of measurement errors in the 2D SSH fields, and to address the challenges posed by the coarse temporal sampling and presence of internal tides in the construction of high-level gridded products and assimilated ocean state estimation.
 

Oral presentation show times:

Room Start Date End Date
The Forum Thu, Oct 24 2019,11:30 Thu, Oct 24 2019,11:45
Lee-Lueng Fu
JPL - CalTech
United States
lee-lueng.fu@jpl.nasa.gov