The Role of Cyclones in Moisture Transport into the Arctic

Abstract In this study, ERA5 reanalysis is used to quantify cyclone‐induced moisture transport into the Arctic on a seasonal basis (1998–2018). Moist airstreams are spatially identified and temporally linked to individual cyclones (50–90°N). Results show that cyclones account for 74% of the annual poleward flux across 70°N. For these cyclone cases, which primarily emerge over the central Arctic in summer or otherwise originate from the North Atlantic, the amount of moisture transport is found to closely depend on track orientation and poleward propagation. Cyclone tracks oriented in the poleward direction along with coupling to an upper‐level vortex which influences the steering flow are the most important characteristics that determine the moisture flux into the Arctic. Back trajectories highlight low‐level moisture source regions over the Atlantic Gulf Stream throughout the year and over the high‐latitude continental land surface during the warm season.