Moisture‐ Versus Wind‐Dominated Flavors of Atmospheric Rivers. Issue 23 (1st December 2020)

• Record Type: Journal Article
• Authors: Gonzales, Katerina R.; Swain, Daniel L.; Barnes, Elizabeth A.; Diffenbaugh, Noah S.
• Is Part Of: Geophysical research letters. Volume 47:Issue 23(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-01
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL090042
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Atmospheric rivers (ARs) are essential features of the global water cycle. Although AR definitions are commonly based on integrated vapor transport (IVT), ARs of a given IVT can induce a wide range of surface precipitation and wind impacts. We develop an AR "flavor" metric that partitions AR IVT into moisture‐dominant and wind‐dominant components. We use this metric to create a climatological catalog of "wet" and "windy" ARs along the U.S. West Coast from 1980 to 2016. Windy ARs are generally associated with stronger surface winds than are wet ARs, with the largest differences at low IVT. Windy ARs are also associated with greater daily precipitation totals than are wet ARs, with the difference widening at higher IVT, notably over mountainous regions. Pacific Northwest ARs have become increasingly moisture dominated over 1980–2016, which has important implications for western U.S. water availability and flood risk. Plain Language Summary: Atmospheric rivers transport large amounts of water vapor and are often associated with heavy precipitation and strong winds. Just as terrestrial rivers have different types, we show that the water vapor transport in atmospheric rivers can have distinct "flavors" and may be dominated by either high levels of moisture or strong winds. We find that atmospheric rivers of differing flavors produce different precipitation amounts and wind speeds. We also find that Pacific Northwest atmospheric rivers have become increasingly moisture dominated over the past four decades. Key Points: Atmospheric rivers (ARs) can be characterized as moisture or wind dominated ("wet" or "windy") For a given level of vapor transport, "windy" ARs generally produce greater precipitation than do "wet" ARs Pacific Northwest ARs are becoming increasingly moisture dominated