ACUSAT Satellite

Remotely-sensed from space, sea surface temperature (SST), ocean color (OC), sun-glitter and surface roughness images often unveil very rich two-dimensional expressions of surface signatures at spatial scales ranging from 1 and 50 km. These signatures include characteristics of upper ocean dynamics associated with meandering frontal zones, jets, eddies, filaments and internal waves. For instance, very well delineated sea surface temperature frontal patterns coincide with very localized intense sea surface roughness variations and patchiness in algae distributions associated with upper layer divergence/convergence areas. Satellite sensor synergetic approach opens up a way to better quantify and map the upper ocean flow characteristics associated with mesoscale and sub-mesoscale dynamics. The challenge is to transform these abundant signatures into consistent oceanographic quantities and processes. In ACUSAT this will be exploited in combination with use of advanced in-situ observations and numerical ocean models.

SENSOR Mesoscale ~50 km Sub-mesoscale ~1-10 km Mesoscale ~50 km Sub-mesoscale ~1-10 km
IR SST fronts of meanders and eddies Sharp fronts and filaments Proxy for density fronts, Surface Quasi-Geostrophic assumption used to estimate along front current, shear and vorticity field Surface Quasi-Geostrophic assumption break down
OC Concentration and distribution of chlorophyll Patchiness Indicative of zones dominated by advective processes Indicative of zones dominated by convergence-downwelling and divergence-upwelling
RA Sea level anomalies Not resolved 2D maps of surface geostrophic current, shear and vorticity field Not resolved
VISIBLE Changes in reflectivity due to influence of sea surface slope Sun-glitter related to local mean square slope (mss) across front Indicative of zones of increased mss due to convergence Indicative of zones of increased mss due to convergence
SAR Backscatter change Strong backscatter change related to change in local mss triggered in convergence and divergence zones Shift in Doppler centroid associated with range Doppler velocity Strong backscatter anomalies associated with rapid shifts in mss across convergence and divergence zones