Atmospheric river, a term encompassing different meteorological patterns

Abstract

The study of atmospheric rivers (ARs) and their impacts on extreme precipitation are currently of great research interest in view of their clear socioeconomical implications. However, studies of this type generally contain caveats. The first of these is of a meteorological nature, and is concerned with the diversity of the different meteorological patterns that can be associated in the phenomenological definition, in that there is no guarantee that all so‐called ARs follow the same one. The second concern involves the initial definition of an AR, which implicitly assumes the subtropical origin of the atmospheric moisture that feeds it. To date, it has been observed that in many cases of ARs, most of the moisture originates in regions at higher latitudes. The aim of this article is to open a debate on these two aspects by using well‐known examples of ARs which fit different meteorological patterns, and showing a climatology of the moisture sources that feed ARs. This article is categorized under: Science of Water > Hydrological Processes Science of Water > Water Extremes

Increases in Future AR Count and Size: Overview of the ARTMIP Tier 2 CMIP5/6 Experiment

“…Such differences in subjective opinion likely also play a role in the quantitative choices made by various ARDT designers. Gimeno et al (2021) add some discussion concerning the diversity of the different meteorological patterns that can be associated with the qualitative definition of ARs, and there is no guarantee that all so-called ARs are associated with the same meteorological patterns. Given this spread in expert opinion, and given that there is no agreed-upon theoretical or numerical definition of what defines an AR, there is presently no way to objectively assess whether one ARDT is better than another.…”

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

“…The opposite is true with respect to JRA-55, as MERRA-2 still has more ARs detected in the subtropics of South America. Whether the SALLJ feature is considered an AR is up for debate (Gimeno et al, 2021). A reanalysis comparison of the SALLJ was performed by Montini et al (2019).…”

Concurrent extreme events of atmospheric moisture transport and continentalprecipitation: the role of landfalling atmospheric rivers

“…Large continental regions downwind of these regions of preferential occurrence of landfalling ARs show percentages greater than 75%, reflecting the effect on inland penetration of ARs (Rutz et al, 2015;Lavers and Villarini, 2015;Nayak and Villarini, 2018;Ralph et al, 2019;Eiras-Barca et al, 2021). There are no percentages higher than 50% in any season in the monsoon regions, where the concurrence between IVT and precipitation is high, showing that in these regions both the definition of ARs and their effects are diffuse (Gimeno et al, 2021). In both hemispheres, the percentage is higher in autumn and winter than in spring and summer, with the exception of the Asian Pacific coasts.…”

“…This problem of distance is not seen in the other major mechanism of moisture transport, ARs, which are non-permanent narrow and long corridors of moisture in the atmosphere (Zhu and Newell, 1994;Gimeno et al, 2014;Ralph et al, 2018). ARs are generally, though not always, associated with extratropical cyclones (Gimeno et al, 2021), and are characterized and even frequently defined by high values of IVT (Neiman et al, 2008). They are closely related to heavy precipitation associated mainly with baroclinic development and orographic forcing (Ralph et al, 2006;Ralph and Dettinger, 2011;Ralph et al, 2016;Tan et al, 2021;Dettinger et al, 2015;Gimeno et al, 2014;Mukherjee and Mishra, 2021a).…”