Atmospheric Rivers

The term “atmospheric river” (AR) was introduced in 1994 to delineate the long and narrow filaments of horizontal water vapor transport that most often occur in midlatitude regions and account for nearly all of the poleward water vapor transport there. Three decades of research has established that ARs have a global presence and are major precipitation deliverers, flood producers, and drought busters in many regions around the world. Numerous efforts have been put into observing and understanding AR characteristics and impacts, and exploring potential sources of subseasonal and longer-term predictability of ARs. Relatively new compared to other well-known weather phenomena, it is expected that AR science will continue to develop and contribute to better understanding of weather and water extremes and management of their impacts on the society.