Seasonal to interannual variability of upper ocean temperature and salinity: the role of Atmospheric Rivers

The ocean is the primary driver of interannual to decadal climate variability. Air-sea exchanges of heat and freshwater on a range of timescales play a key role in these modes of variability, yet our understanding of relevant processes is incomplete, largely due to limited long-term observations of the coupled climate system. Particularly poor is our understanding of air-sea exchanges during high impact events (e.g., tropical cyclones, mid-latitude storms, atmospheric rivers, marine heat waves), as they are less frequent, occur at relatively short time scales and on small spatial scales, depend on the preconditioning of the system, and hence are challenging to observe and model.

We use in situ and satellite observations to study the role of Atmospheric Rivers (ARs) for seasonal to interannual variability of upper ocean temperature and salinity. ARs are filamentary structures in the atmosphere that transport water vapor from the tropics to mid-latitudes over the oceans in highly episodic events. They are shown to be a major source of rainfall in the western United States, they impact Greenland and Antarctic ice melt events, and they play a role in exchanges of heat and freshwater at the air-sea interface.