Changes in atmospheric rivers and moisture transport over the Northeast Pacific and western North America in response to ENSO diversity

Kim, Hye‐Mi; Yang, Zhiyong; Alexander, Michael A.

doi:10.1007/s00382-017-3598-9

Cited by 66 publications

(86 citation statements)

References 34 publications

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“…The AR frequency is conventionally defined as the grid‐point accumulated number of such AR objects over a certain period. Variability and predictability of AR frequency from subseasonal to seasonal time scales have been widely studied (Baggett et al, ; DeFlorio, Waliser, Guan, Lavers et al, ; DeFlorio, Waliser, Guan, Ralph et al, ; Guan & Waliser, ; Kim et al, ; Mundhenk, Barnes, Maloney, ; Mundhenk, Barnes, Maloney, Nardi, ; Mundhenk et al, ; Payne & Magnusdottir, ; Zhou & Kim, ). Alternatively, numerous studies investigate the temporal transportation of moisture related to ARs via the Lagrangian trajectory model.…”

Section: Introductionmentioning

confidence: 99%

Life Cycle of Atmospheric Rivers: Identification and Climatological Characteristics

2018

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An atmospheric river (AR) event is a strong poleward moisture transport that is composed of a series of spatiotemporally connected instantaneous AR objects. A new object‐based tracking algorithm is developed in this study, which aims to identify an AR event and investigate its life cycle from origin to termination. The algorithm identifies duration, intensity, propagation speed and direction, and the traveled distance throughout the life cycle of the AR event. The tracking algorithm is applied to 6‐hourly column‐integrated water vapor flux from November to March during the period of 1979–2017, with a focus on the North Pacific. Most North Pacific AR events originate in the subtropics over the Northwest Pacific and terminate at higher latitudes over the Northeast Pacific including western North America. On average, long AR events that last more than 72 hrs travel 7 times longer in distance and have stronger intensity than short AR events that last less than 24 hrs. Finally, a new accumulated AR intensity index is developed, which summarizes the overall impact of AR events over a given domain during a certain period by incorporating number, lifetime, and intensities of AR events.

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Section: Introductionmentioning

confidence: 99%

Life Cycle of Atmospheric Rivers: Identification and Climatological Characteristics

2018

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“…Upper-level circulation observed during AR landfalls in Northern California (Neiman et (Neiman et al, 2008) feature a prominent high-low couplet with a gradient parallel to the coast, which acts to channel wind and moisture onshore. Recent work highlighted links between regional AR activity and circulation features associated with common teleconnection patterns such as the Pacific North American Pattern (PNA; Guan & Waliser, 2015), Arctic Oscillation (Guan et al, 2013), El Niño Southern Oscillation (ENSO; Ryoo et al, 2013;Kim & Alexander, 2015;Kim et al, 2017), Pacific Decadal Oscillation (PDO; GSR'17), Madden-Julian Oscillation (MJO; Guan & Waliser, 2015), and the MJO jointly with the quasi-biennial oscillation (Baggett et al, 2017;Mundhenk et al, 2018). Recent work highlighted links between regional AR activity and circulation features associated with common teleconnection patterns such as the Pacific North American Pattern (PNA; Guan & Waliser, 2015), Arctic Oscillation (Guan et al, 2013), El Niño Southern Oscillation (ENSO; Ryoo et al, 2013;Kim & Alexander, 2015;Kim et al, 2017), Pacific Decadal Oscillation (PDO; GSR'17), Madden-Julian Oscillation (MJO; Guan & Waliser, 2015), and the MJO jointly with the quasi-biennial oscillation (Baggett et al, 2017;Mundhenk et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Circulation Drivers of Atmospheric Rivers at the North American West Coast

Guirguis

Gershunov

Clemesha

et al. 2018

Geophysical Research Letters

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Atmospheric rivers (ARs) are mechanisms of strong moisture transport capable of bringing heavy precipitation to the West Coast of North America, which drives water resources and can lead to large‐scale flooding. Understanding links between climate variability and landfalling ARs is critical for improving forecasts on timescales needed for water resource management. We examined 69 years of landfalling ARs along western North America using reanalysis and a long‐term AR catalog to identify circulation drivers of AR landfalls. This analysis reveals that AR activity along the West Coast is largely associated with a handful of influential modes of atmospheric variability. Interaction between these modes creates favorable or unfavorable atmospheric states for landfalling ARs at different locations, effectively steering moisture plumes up and down the coast from Mexico to British Columbia. Seasonal persistence of certain modes helps explain interannual variability of landfalling ARs, including recent California drought years and the wet winter of 2016/2017.

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“…The model could potentially improve extreme precipitation prediction using predictors of enhanced moisture transport and evolution of circulation patterns in favor of moisture convergence prior to the occurrence of extremes. The evolutions of the anomalous circulation patterns and the moisture fluxes for the Yangtze top 5% extreme precipitation period, from 7 days ahead up to the extreme precipitation days (Figure 8), shows that there is a strong low-pressure system sitting over the Yangtze river basin [25][26][27][28][29][30][31][32][33][34] • N, 100 • E-122 • E], forming 6 days ahead with a high-pressure system sitting to its north. There is also a strong low-pressure system formed in the North Pacific Ocean, almost at the same time with the one over the Yangtze river basin.…”

Section: The Role Of Atmospheric Circulation In Extremesmentioning

confidence: 99%

Diagnosis of the Tropical Moisture Exports to the Mid-Latitudes and the Role of Atmospheric Steering in the Extreme Precipitation

Hao

2017

Atmosphere

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Three river basins, i.e., the Yangtze river, the Mississippi river and the Loire river, were presented as case studies to explore the association among atmospheric circulations, moisture exports and extreme precipitations in the mid-latitudes. The major moisture source regions in the tropics for the three river basins are first identified using the Tropical Moisture Exports (TMEs) dataset. The space-time characteristics of their respective moisture sources are presented. Then, the trajectory curve clustering analysis is applied to the TMEs tracks originating from the identified source regions during each basin's peak TMEs activity and flood seasons. Our results show that the moisture tracks for each basin can be categorized into 3 or 4 clusters with distinct spatial trajectory features. Our further analysis on these clustered trajectories reveals that the contributions of moisture release from different clusters are associated with their trajectory features and travel speeds. In order to understand the role of associated atmospheric steering, daily composites of the geopotential heights anomalies and the vertical integral of moisture flux anomalies from 7 days ahead to the extreme precipitation days (top 5%) are examined. The evolutions of the atmospheric circulation patterns and the moisture fluxes are both consistent with the TMEs tracks that contribute more moisture releases to the study regions. The findings imply that atmospheric steering plays an important role in the moisture transport and release, especially for the extreme precipitations. We also find that the association between TMEs moisture release and precipitation is nonlinear. The extreme precipitation is associated with high TMEs moisture release for all of the three study regions.

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Changes in atmospheric rivers and moisture transport over the Northeast Pacific and western North America in response to ENSO diversity

Cited by 66 publications

References 34 publications

Life Cycle of Atmospheric Rivers: Identification and Climatological Characteristics

Life Cycle of Atmospheric Rivers: Identification and Climatological Characteristics

Circulation Drivers of Atmospheric Rivers at the North American West Coast

Diagnosis of the Tropical Moisture Exports to the Mid-Latitudes and the Role of Atmospheric Steering in the Extreme Precipitation

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