The world's oceans are turbulent. In the first several hundred meters of the upper ocean, vigorous small mesoscale (<~100km) ocean circulation can transport heat, carbon and other oceanic tracers such as nutrients between the sea surface and the deeper ocean (Lévy et al., 2012; Su et al., 2018). These vertical exchanges ventilate the global ocean, support marine ecosystems, and modulate the Earth’s climate.

This animation depicts these vigorous upper ocean turbulent circulations by rendering the ocean temperature on a cold-warm color palette. Blue represents the colder (denser) water mostly found in the deeper and/or higher latitude oceans. Red color represents the warmer sea water found on the upper layers of the ocean. Oceanic fronts, similar to the fronts in the atmosphere that generate strong winds and weather, are formed in the upper ocean when cold and warm waters meet sideways. These fronts and their evolution are associated with strong vertical mixing and transports. The ocean circulations shown in this animation are not observable by the current satellite altimeters. The animation is based on a global ocean numerical simulation, the ECCO simulation 1/48 (LLC4320).

However, the Surface Water and Ocean Topography (SWOT) mission will be able to provide us with measurements toward deriving a global view of small-scale ocean circulation for the first time (Morrow et al., 2019; Qiu et al., 2019). The SWOT satellite is scheduled to launch November 2022. In addition to measuring the ocean topography, the satellite will also measure the size and height of land waters and sea ice edges. This will be the first of its kind satellite mission that comprehensively observes the global water bodies including lakes, rivers, estuaries, coastal and open oceans to address the global water cycle and ocean’s influence on climate change.