Precipitation regime change in Western North America: The role of Atmospheric Rivers

TitlePrecipitation regime change in Western North America: The role of Atmospheric Rivers
Publication TypeJournal Article
Year of Publication2019
AuthorsGershunov A, Shulgina T., Clemesha R.ES, Guirguis K., Pierce DW, Dettinger MD, Lavers D.A, Cayan DR, Polade S.D, Kalansky J., Ralph FM
Volume9
Date Published2019/07
Type of ArticleArticle
ISBN Number2045-2322
Accession NumberWOS:000474505900055
Keywordscalifornia; climate-change; CMIP5; events; extreme precipitation; Hadley circulation; multimodel; projection; Science & Technology - Other Topics; us; variability
Abstract

Daily precipitation in California has been projected to become less frequent even as precipitation extremes intensify, leading to uncertainty in the overall response to climate warming. Precipitation extremes are historically associated with Atmospheric Rivers (ARs). Sixteen global climate models are evaluated for realism in modeled historical AR behavior and contribution of the resulting daily precipitation to annual total precipitation over Western North America. The five most realistic models display consistent changes in future AR behavior, constraining the spread of the full ensemble. They, moreover, project increasing year-to-year variability of total annual precipitation, particularly over California, where change in total annual precipitation is not projected with confidence. Focusing on three representative river basins along the West Coast, we show that, while the decrease in precipitation frequency is mostly due to non-AR events, the increase in heavy and extreme precipitation is almost entirely due to ARs. This research demonstrates that examining meteorological causes of precipitation regime change can lead to better and more nuanced understanding of climate projections. It highlights the critical role of future changes in ARs to Western water resources, especially over California.

DOI10.1038/s41598-019-46169-w
Student Publication: 
No