Plain Language Summary
Atmospheric rivers occur thin, river-like, streams of moisture
connecting the mid- and high-latitudes to the tropics often associated
with extratropical storms. These events are regions that have large
amounts of moisture and can generate heavy precipitation. We show that
moisture and energy fueling the ARs do not come from the ocean directly
beneath the ARs. First, we use a dataset derived from satellite
retrievals of surface winds to demonstrate that the energy transferred
into ARs from the ocean are weaker than usual during AR events. Then we
use a global climate model to show that the origins of the moisture in
the ARs arrives via atmospheric transport from regions outside of the
ARs, farther away and nearer to the equator.