Role of atmospheric moisture sources and pathways in the seasonality of extreme precipitation over the eastern United States

Abstract

The empirical probability distribution of extreme precipitation in the eastern United States comprises heavy rainfall events stemming from the moisture held by the Atmospheric Rivers (ARs). In many sites, ARs trajectories can have varying impacts on the extreme precipitation seasonality based on the moisture source and tracks. Consequently, a characterization of location specific and regional patterns of timing of extreme precipitation caused by ARs and their non-stationarity has salience for both scientific and engineering concerns. To this end, analysis of annual maximum daily precipitation (AMP) at 581 long-term stations across the eastern United States was pursued in this study to evaluate the role of moisture sources and tracks in the seasonality of extreme rainfall-AR related events (AMP-AR) and their temporal changes over the 1950–2015 period. The key results from this study include: (a) spatio-temporal variation in the fraction of annual maximum precipitation events linked to ARs, and (b) a marked influence of moisture sources on the seasonality of AMP-AR related events. Results from this study have important bearing on the flood risk management and preparedness.