An Overview of ARTMIP's Tier 2 Reanalysis Intercomparison: Uncertainty in the Detection of Atmospheric Rivers and Their Associated Precipitation

Atmospheric rivers, or long but narrow regions of enhanced water vapor transport, are an important component the hydrologic cycle as they responsible for much poleward transport and result in precipitation, sometimes extreme intensity. Despite their importance, uncertainty remains detection atmospheric rivers large datasets such reanalyses century scale climate simulations. To understand this uncertainty, River Tracking Method Intercomparison Project (ARTMIP) developed tiered experiments, including Tier 2 Reanalysis that is presented here. Eleven algorithms submitted hourly tags--binary fields indicating presence absence rivers--of detected Modern Era Retrospective Analysis Research Applications, version (MERRA-2) European Centre Medium-Range Weather Forecasts’ Version 5 (ERA5) well six-hourly tags Japanese 55-year (JRA-55). Due to a higher climatological mean integrated MERRA-2, were more frequently relative other two reanalyses, particularly use fixed threshold transport. The finer horizontal resolution ERA5 resulted narrower ability detect along resolved coastlines. fraction hemispheric area covered by ARs varies throughout year all three with different river tools having seasonal cycles. This article protected copyright. All rights reserved.