‘Where did all this rain come from?’ The role of air-sea interactions
It is well known that extreme precipitation from cyclones can lead to flooding events. However, the mechanisms by which water vapour is supplied to cyclones and converted into precipitation are a subject of scientific debate. Many studies suggest that water vapour evaporating from the sea surface in the subtropics is supplied to cyclones via poleward transport along the cold front, in an airflow known as an atmospheric river. In this talk we propose an alternative supply route, whereby water vapour evaporating from the sea surface in the environment ahead of the cyclone is swept up by the travelling cyclone, in a cyclone-relative airflow termed the feeder airstream. The feeder airstream provides the missing link between air-sea fluxes, cyclone warm conveyor belts and atmospheric rivers.