Where does the link between atmospheric moisture transport and extreme precipitation matter?

Abstract

Atmospheric moisture transport is the primary component of the atmospheric branch of the water cycle, and its anomalies strongly influence drought and precipitation extremes. We utilised the full geographical and temporal spectrum of the ERA-5 reanalysis data and extreme value theory to identify regions where the atmospheric moisture transport, quantified as local integrated moisture vertical transport (IVT), influences daily extreme precipitation, and where this influence has a relevant dynamic component, which may alter the dependency between IVT and extreme precipitation as temperatures increase with climate change. We showed that this dependency is weak or negligible in tropical regions and strong but nonuniform in extratropical regions. Its influence is much greater in areas where the main moisture transport mechanisms occur, namely, atmospheric rivers, low-level jets, and tropical cyclones. The dynamic component of IVT, linked to wind, is highly consequential in regions with landfalling atmospheric rivers, landfalling tropical cyclones, or moisture-transporting low-level jets.