Measuring currents, ice drift, and waves from space: the Sea Surface KInematics Multiscale monitoring (SKIM) concept

Abstract

Abstract. We propose a new satellite mission that uses a near-nadir Ka-band Doppler radar to measure surface currents, ice drift and ocean waves at spatial scales of 40 km and more, with snapshots at least every day for latitudes 75 to 82, and every few days otherwise. The use of incidence angles at 6 and 12 degrees allows a measurement of the directional wave spectrum which yields accurate corrections of the wave-induced bias in the current measurements. The instrument principle, algorithm for current velocity and mission performance are presented here. The proposed instrument can reveal features on tropical 5 ocean and marginal ice zone dynamics that are inaccessible to other measurement systems, as well as a global monitoring of the ocean mesoscale that surpasses the capability of today's nadir altimeters. Measuring ocean wave properties facilitates many applications, from wave-current interactions and air-sea fluxes to the transport and convergence of marine plastic debris and assessment of marine and coastal hazards. 1Ocean Sci. Discuss., https://doi

Surface Kinetic Energy Distributions in the Global Oceans From a High‐Resolution Numerical Model and Surface Drifter Observations

“…This disentanglement will be a challenge for SWOT (Ponte et al, ). It will probably be a larger one for SKIM where near‐inertial waves contamination will be more significant than for SWOT (Ardhuin et al, ). Fortunately for SKIM, it will measure currents, that is, the same variable readily deduced from drifter trajectories.…”

“…However, one common issue with altimetric data, as well as with other types of satellite observations in general, arises from the long repeat sampling cycles and therefore limited temporal resolution which complicates the disentanglement of signals with different temporal scales (e.g., slow balanced geostrophic motions and fast unbalanced internal gravity waves; Chavanne & Klein, ). The issue of temporal sampling is critical for the SWOT mission (21‐day repeat sampling) and other satellite missions that are under development such as the Surface KInematic Monitoring (SKIM) mission (Ardhuin et al, ).…”

Ocean‐Scale Interactions From Space

“…The latter missions include WaCM (Rodríguez et al, ), already mentioned, that will observe simultaneously the wind stress and oceanic currents at very high resolution and therefore give access to near‐inertial waves and smaller IGWs. They also include other missions such as the Surface KInematic Monitoring mission (Ardhuin et al, ) and the Wavemill mission (Martin et al, ) aiming to observe surface currents with high resolution. An optimal strategy to better capture the subtleties of ocean turbulence would be to exploit the synergy of analyzing all these satellite observations in combination with in situ data on a global scale, such as the ones collected by surface drifters (Lumpkin et al, ) and ARGO floats (Le Traon, ) deployed in all oceans.…”

Satellites will address critical science priorities for quantifying ocean carbon

“…Future satellite missions will expand these capabilities; the recently proposed Sea surface KInematics Multi‐scale monitoring (SKIM; Ardhuin et al . ) and the Surface Water and Ocean Topography (SWOT; eg Oubanas et al . ) satellites will, by observing wind–wave–current interactions, enable the first direct spatial measurements of surface and vertical water transport.…”