What is "precipitationshed"

A precipitationshed is the upwind ocean and land surface that contributes evaporation to a given, downwind location's precipitation. The concept has been described as an "atmospheric watershed". The concept itself rests on a broad foundation of scholarly work examining the evaporative sources of rainfall. Since its formal definition, the precipitationshed has become an element in water security studies, examinations of sustainability, and mentioned as a potentially useful tool for examining vulnerability of rainfall dependent ecosystems.