Atmospheric rivers (ARs) are long, narrow filaments of enhanced moisture transport and are often associated with heavy precipitation and flooding in the mid-latitudes. In the polar regions, ARs result in heavy precipitation and have a large impact on the energy and moisture budgets. The role of the ARs in the Arctic climate system is an active area of research due to the potential impacts on features such as sea ice and ice sheet melt. ARs impact the Arctic climate system through enhanced atmospheric heat (AHT) and moisture transport into the Arctic and by altering the local surface energy budget as a result of changes in cloud cover. One factor that makes comparisons across AR studies, and thus conclusions regarding the impact of ARs, a challenge is the wide range AR detection algorithms used by the research community. Many AR detection algorithms have been developed for low or mid-latitude applications, while others have been tailored for use in the polar regions.

In this work, we assess the atmospheric heat and moisture transport into the Arctic using 11 AR detection algorithms that have been contributed to the ARTMIP (Atmospheric River Tracking Method Intercomparison Project) Tier 2 Catalogues using ERA5 reanalysis. Specifically, we assess how the zonal average of AR frequency, atmospheric heat (represented by moist static energy) and moisture (integrated water vapor transport - IVT) transport varies from 60 to 88 °N. We find AR frequency ranges from greater than 10% to less than 2% depending on the AR detection method. These differences in AR frequency result in large differences in AHT and IVT. Similar analyses of the impact of ARs on surface downwelling longwave radiation (LWD) show large differences across the AR detection methods considered in this study. For example, in winter, anomalies of LWD during AR events vary from >100 W m^-2 to <50 W m^-2, while the fraction of the seasonal integrated LWD attributed to ARs varies from >10% to <1%, depending on the AR detection algorithm. The differences in AR frequency, AHT, IVT and LWD across the AR detection methods are largest in the winter. There is also a large contrast in the results between AR detection methods designed for use in the polar regions compared to those for use at lower latitudes.