Moisture- and Wind-Dominated Atmospheric Rivers in the Arctic

Atmospheric Rivers (ARs) can be classified into moisture- and wind-dominated ARs. This dataset contains six-hourly footprints of Arctic ARs split into moisture- and wind-dominated gridcells, as well as the moisture dominance itself. ARs are detected via the 2nd version of the Guan and Waliser algorithm published by Lauer et al. (2023); based on the ERA5 reanalysis (Hersbach et al., 2020, 2023) north of 65°N, on a 1.125°x1.125° grid, from 1979-2021. The differentiation into moisture- and wind-dominated ARs is based on the method developed by Gonzales et al. (2020), performed for each gridcell with adjusted vertical integration limits (surface air pressure to 300hPa). First, two indices of Integrated Water Vapor Transport (IVT) are calculated once with the climatological windspeeds, and once with the climatological specific humidity. These indices are standardized and subsequently the moisture dominance is derived from these indices. Gridcells with a moisture dominance within the upper tertile are considered moisture-dominated (or wet) ARs, and within the lower tertile wind-dominated (or windy) ARs.