Abstract
Previous examination of rain gauge observations over a five-year period at high elevations within a river basin of the southern Appalachian Mountains showed that half of the extreme (upper 2.5%) rainfall events were associated with an atmospheric river (AR). Of these extreme events having an AR association, over 73% were linked to a societal hazard at downstream locations in eastern Tennessee and western North Carolina. Our analysis in this study was expanded to investigate AR effects in the southern Appalachian Mountains on two river basins, located 60 km apart, and examine their influence on extreme rainfall, periods of elevated precipitation and landslide events over two time periods, the ‘recent’ and ‘distant’ past. Results showed that slightly more than half of the extreme rainfall events were directly attributable to an AR in both river basins. However, there was disagreement on individual ARs influencing extreme rainfall events in each basin, seemingly a reflection of its proximity to the Blue Ridge Escarpment and the localized terrain lining the river basin boundary. Days having at least one landslide occurring in western North Carolina were found to be correlated with long periods of elevated precipitation, which often also corresponded to the influence of ARs and extreme rainfall events.
Highlights
Atmospheric Rivers (ARs) are narrow and elongated zones of rapid, anomalously moist air at low levels originating from the sub-tropics and located just ahead of the surface cold front in mid-latitude cyclones, responsible for a significant portion of poleward vapor and latent heat transport (e.g., References [1,2,3,4])
Of 33 ARs detected by the new algorithm not flagged by the Global Forecast System (GFS)-based technique, all but three ARs were qualified either as weak or as not meeting the shape criterion as defined in Mahoney et al [22] or as not impacting the Miller et al [5] integrated horizontal water vapor transport (IVT) study domain for at least 12 h
Our analysis showed that ARs account for the majority (53–59%) of extreme rainfall events compared to tropical cyclones and occur most often in winter and least often in summer
Summary
Atmospheric Rivers (ARs) are narrow and elongated zones of rapid, anomalously moist air at low levels originating from the sub-tropics and located just ahead of the surface cold front in mid-latitude cyclones, responsible for a significant portion of poleward vapor and latent heat transport (e.g., References [1,2,3,4]). These important features can be responsible for just over half of the extreme (top 2.5%) rainfall events in the Southeastern U.S and societal hazards originate from a majority of these events (e.g., flooding, landslides) [5]. The importance of ARs has been documented in a variety of climate zones, and across the globe (e.g., References [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28]).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
