Persistent landfalling atmospheric rivers over the west coast of North America

Citations Over TimeTop 12% of 2016 papers

Abstract

Abstract Landfalling atmospheric rivers (ARs) are linked to heavy precipitation and extreme flooding, and are well known along the western coast of North America. The hydrological impacts of ARs upon landfall are correlated with their duration and magnitude. In order to improve the forecast of these hydrologically significant landfalling events, a better understanding of how they differ from other landfalling events must be established through an investigation of the mechanisms leading to their development prior to landfall. A subset of persistent landfalling AR events between 30°N and 50°N is identified in 3‐hourly Modern‐Era Retrospective Analysis for Research and Applications reanalysis and validated against existing data sets. These events are identified as features in the low troposphere with high moisture transport and extended geometry that persist over a limited region of the coastline for longer than 63 h (85th percentile of AR duration). A composite analysis shows that persistent events have distinct thermodynamical and dynamical characteristics compared to all AR events. They are characterized by greater moisture content, suggestive of Pineapple Express‐type events, a perturbed upper level jet and anticyclonic overturning of potential vorticity contours associated with anticyclonic Rossby wave breaking. Moreover, the location of the Rossby wave breaking is shifted inland compared to all AR events. Analogue analysis of the 500 hPa geopotential height anomalies is used to find nonpersistent events with similar dynamical characteristics to persistent events. Despite their similarity to persistent events, nonpersistent analogues show very little shift toward longer duration. A comparison of the development of persistent and nonpersistent analogues shows that persistent events have much greater moisture content.

Related Papers

• → A critical comparison of stratosphere–troposphere coupling indices(2009)284 cited
• → Effects of Rossby Waves Breaking and Atmospheric Blocking Formation on the Extreme Forest Fire and Floods in Eastern Siberia 2019(2023)23 cited
• → Characterizing quasi-biweekly variability of the Asian monsoon anticyclone using potential vorticity and large-scale geopotential height field(2020)7 cited
• Analysis on 10 hPa Polar Vortex Multi-Scale Variable Characteristic in the Southern Hemisphere(2009)
• → Intraseasonal Variability of Anticyclonic Rossby Wave Breaking and Its Impact on Tropical Cyclone Activity over the Western North Pacific(2024)