CFOSAT Scientific Objectives

Main objectives regarding the ocean surface

CFOSAT is designed to provide at the global scale, observations of wind at the ocean surface and spectral properties of surface ocean waves. The objective is multifold. It will serve both operational needs for the surface wind and wave forecast (marine meteorology and climatology), and research needs by improving our knowledge on the hydrodynamics of the waves, on the interactions between waves and the atmospheric or oceanic layers close to the surface, and on the interactions between electromagnetic signals and the ocean surface.

These main objectives can detailed as:

Modeling and prediction of ocean surface wind and waves
Physical processes of wind and wave
Interactions between surface waves, atmosphere and ocean
Interactions between electromagnetic signals and the ocean surface
Wave evolution in coastal region

Opportunity studies of polar ice sheet and land surface processes

The objectives listed below are secondary objectives to the CFOSAT mission, and specifications specific to these goals are to be met on a best effort basis.

Polar ice sheet
Land surfaces

Scientific requirements to fulfill the objectives of CFOSAT

The payload is composed of two instruments: a wind-scatterometer (SCAT) and a wave-scatterometer spectrometer (SWIM: Surface Waves Investigation and Monitoring instrument). The requirements are:

to estimate directional spectra of ocean waves along the satellite track at scales ranging from 50 x 50 km² to 70 x 70 km²
to transmit data in near real-time within 3 hours after acquisition
to estimate wind speed and significant wave height from nadir-looking beam, in a way similar to altimeter missions
to estimate the wind vector over a swath of about 900 km with a nominal resolution of 50 x 50 km² (goal 25 x 25 km²)
to sample spectral wave properties with a global coverage at a temporal scale of 10 to 15 days
to sample wind with a global coverage at a temporal scale of 1 to 2 day
accuracy for wave estimates: minimum detectable wavelength of about 70 m, maximum detectable wavelength about 500m, accuracy in wave propagation direction of about 15°, accuracy in wavelength of 10 to 20%, accuracy in significant wave height of 10% or better than 40-50 cm (TBC)
accuracy on wind speed estimates of ±2m/s or 10% (whichever is larger) and on wind direction of ±20° in the range 4-24 m/s
to estimate the radar cross-section dependence with incidence (from 0 to 10° and from 18 to 50° for SWIM and SCAT, respectively) and azimut, in order to derive from these profiles:

Properties on the statistics of the sea surface slope (mean square slope, shape of the slope probability density function)
Estimate of wind direction and wind speed
In the polar ice sheet, the contribution of volume scattering with respect to surface scattering, and ice surface and snow pack characteristics
Humidity and roughness of bare soils over land surface