A Framework to Delineate Precipitation-Runoff Regimes: Precipitation vs. Snowpack in the Western U.S.

Journal Article · Thu Nov 28 04:00:00 EST 2019 · Geophysical Research Letters

DOI:https://doi.org/10.1029/2019GL085184· OSTI ID:1580113

Chen, Xiaodong ^[1]; Duan, Zhuoran ^[1]; Leung, Lai-Yung ^[1]; Wigmosta, Mark S. ^[1]

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1. BATTELLE (PACIFIC NW LAB)

We propose a framework to classify precipitation events accompanied by snow process (precipitation-and-snow, or PAS events) into five regimes, based on the relative contributions of snowpack change and precipitation amount to the runoff response. This framework is applied to a regional climate simulation over the western U.S. to reveal the regions where snow process plays important roles. Over the western U.S., PAS events account for 50-90% of all the precipitation events. About 60-80% of PAS events feature snow accumulation, but snow melting frequently happens in high-elevation areas. Compared with snow accumulation events, snow melting events have a more limited spatial distribution. Different regimes peak in different months between early winter and late spring. Lastly, the impact of atmospheric rivers is investigated. Although accounting for only 2% of the grid-scale precipitation events, atmospheric rivers trigger significant snowmelt and contribute to 20% and 11% of light and heavy snow melting events, respectively.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1580113
• Report Number(s): PNNL-SA-141385
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 22 Vol. 46
• Country of Publication: United States
• Language: English