Description:

Atmospheric rivers (ARs) are long, narrow filamentary structures that involve intensive water vapor transport in the lower troposphere and are essential to the global hydrological cycle. They are often associated with extreme winter storms and heavy precipitation along the western coasts of mid-latitude continents and have the ability to produce major flooding events and/or relieve droughts. Understanding how ARs may vary from subseasonal-to-interannual time scale and change in a warmer climate is critical to advancing understanding and prediction of regional precipitation. 

However, the definition of an atmospheric river is still widely debated and often depends on  science questions or purpose. Quantifying uncertainty in AR science, which may originate from detection methodology, reanalysis products, initial condition, and model error or spread, plays a crucial role in assessing confidence in process-level and impact-orientated AR analysis and predictions. Grassroots efforts to address and characterize these uncertainties have produced such projects as ARTMIP, the Atmospheric River Tracking Method Intercomparison Project (ARTMIP), which aims to quantify the uncertainty in AR climatology (e.g., frequency, duration, and intensity), precipitation, and related impacts that arise because of different AR tracking methods, and uncertainty in how these AR-related metrics may change in the future. ARTMIP also aims to provide guidance regarding the advantages and disadvantages of different AR tracking methods and which of these methods are best suited to answer certain scientific questions.

This session focuses on ARs and uncertainty quantification across a range of scientific foci such as AR development, driving mechanisms, dynamical and thermodynamical responses to climate change, linkage with multi-scale climate variability, and hydrological impacts. Abstracts which make use of data from the Atmospheric River Tracking Method Intercomparison Project to quantify and elucidate the implication of uncertainty are encouraged.