Influence of atmospheric rivers on extreme rainfall and high streamflow events in northwestern Europe: Rur (Roer) River basin

Abstract

Study region: Limburg, the Netherlands; west Germany; Rur / Roer River basin. Study focus: Atmospheric rivers (ARs) are long (≥ 2000 kilometers) tropospheric bands of water vapor responsible for 90% of poleward atmospheric water transport linked to extreme rainfall events (EREs). The meteorological impacts of ARs have been well-studied in high-relief regions with the implication being that rainfall generated by such events is exacerbated by the orographic influence of mountainous topography. While prior research has examined linkages between ARs and precipitation with ad-hoc flood events, few studies have systematically examined the influence of ARs to streamflow variability in regions low-to-moderate relief. We assess the effects of ARs on high precipitation and high streamflow events in northwestern Europe, and specifically for the Rur (Roer) River basin, a region characterized by low to moderate relief that has received little hydrologic research attention related to atmospheric rivers. New hydrological insights for the region: The study is novel in that it reveals that daily precipitation and streamflow are significantly increased, by 2.84 mm and 1.91 m3/s, respectively, during AR conditions. Moreover, 47.7% of EREs and 23.2% of high streamflow events were found to be associated with ARs. An AR occurrence also increases the likelihood of a rain day occurring by 36.6%. Lastly, AR presence was significantly correlated (p < 0.001) with precipitation (ρ = 0.33). Study results illustrate that ARs are important to understanding EREs and high streamflow events, which is relevant considering a predicted increase in AR occurrence due to climate change.

Keywords

• Atmospheric rivers
• Streamflow variability
• Rur River
• Roer River
• Extreme rainfall events
• Precipitation variability