Animation Credit: Shigeru Suzuki   

Since the beginning of the 1990s, satellite altimeters have been measuring sea surface height (SSH) from space. Maps of SSH have widespread use among the scientific and operational oceanography and climate science community including monitoring the global mean sea level and El Niño Southern Oscillation, forecasting hurricane intensification, tracking large scale eddies and ocean fronts, and estimating ocean circulation, to name just a few. These altimeters have been monitoring SSH at mesoscale. The spatial resolution of the SSH maps has been evolving from ~300 km in the 1990s to ~100 km at present. However, SSH measurements at higher resolution are necessary for monitoring the ocean's vertical heat and carbon transport, which is extremely important to study global climate change.

The Surface Water Ocean Topography (SWOT) mission will be launched at the end of 2022 and will allow global observations of SSH at unprecedented spatial resolution of about 15 km.

This animation illustrates the evolution of the spatial resolution in the global gridded SSH maps using the ECCO 1/12-deg simulation daily SSH maps. Particularly, the animation visualizes the SSH maps at spatial resolutions ranging from 3 to 2 to 1 degree to 15 km (the expected resolution of SWOT observations). Blue patterns show regions of low sea surface height, while the red patterns show regions of high sea surface height. Small scale features such as fronts, meanders and eddies in the Gulf Stream, California Current, or Agulhas Current regions that are not captured at resolutions higher than 1 degree become visible in the 15-km resolution maps. It clearly illustrates the dramatic increase in observability of small-scale ocean circulation.

A simulation of the SWOT orbit and wide-swath measurement grids are shown at the end of this animation.