Climatological Relationship between Warm Season Atmospheric Rivers and Heavy Rainfall over East Asia

Abstract

Eddy transport of atmospheric water vapor from the tropics is important for rainfall and related natural disasters in the middle latitudes. Atmospheric rivers (ARs), intense moisture plumes that are typically associated with extratropical cyclones, often produce heavy precipitation upon encountering topography on the west coasts of mid-latitude North America and Europe. ARs also occur over the northwestern Pacific and sometimes cause floods and landslides over East Asia, but the climatological relationship between ARs and heavy rainfall in this region remains unclear. Here we evaluate the contribution of ARs to the hydrological cycle over East Asia using high-resolution daily rainfall observations and an atmospheric reanalysis during 1958 -2007. Despite their low occurrence, ARs account for 14 -44 % of the total rainfall and 20 -90 % of extreme heavy-rainfall events during spring, summer, and autumn. AR-related extreme rainfall is especially pronounced over western-to-southeastern slopes of terrains over the Korean Peninsula and Japan, owing to strong orographic effects and a stable direction of low-level moisture flows. A strong relationship between warm-season AR heavy rainfall and preceding-winter El Niño is identified since the 1970s, suggesting the potential of predicting heavy-rainfall risk over Korea and Japan at seasonal leads. Keywords ENSO; atmospheric river; Indo-western Pacific Ocean Capacitor; heavy rainfall Corresponding author: Youichi Kamae, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan E-mail: kamae.yoichi.fw@u.tsukuba.ac.jp J-stage Advance Published Date: 7 September 2017 ©2017, Meteorological Society of Japan Journal of the Meteorological Society of Japan Vol. 95, No. 6 412 water vapor transports by atmospheric disturbances, including tropical cyclones (e.g., Eckhardt et al. 2004;Knippertz and Wernli 2010;Boutle et al. 2011; Hawcroft et al. 2012;Newman et al. 2012), are critically important for land hydrology (e.g., heavy rainfalls) and natural disasters (e.g., droughts, floods, and landslides). Atmospheric rivers (ARs), narrow elongated water vapor plumes typically associated with extratropical cyclones, are frequently observed over the mid-latitude Northern and Southern Hemispheres (especially, over the Pacific and Atlantic Ocean; e.g., Zhu and Newell 1998;Ralph et al. 2004; Gimeno et al. 2016; American Meteorological Society 2017). ARs greatly impact water availability and natural disasters over the mid-latitude coastal regions; therefore, they have attracted much attention.While ARs have been a focus of numerous case studies (e.g., Ralph et al. 2004Ralph et al. , 2011Bao et al. 2006;Stohl et al. 2008;Moore et al. 2012), their large-scale climatologies have been characterized recently using atmospheric reanalyses. Mundhenk et al. (2016) examined the basin-wide climatology and variability of the North Pacific ARs by applying an objective detection algorithm (detailed in Section 2.2). Guan and Waliser (2015) ...

Ocean warming pattern effects on future changes in East Asian atmospheric rivers

“…The detection scheme can filter out circular IVT anomalies associated with tropical cyclones via the shape criterion (see figure A2 of Mundhenk et al 2016). Note that ARlike IVT anomalies examined in this study are sometimes influenced by remote effects of tropical cyclone (Kamae et al 2017c). AR frequency examined in this study is defined as the fraction of time periods during which an AR exists to the total number of periods.…”

“…Atmospheric rivers (ARs), narrow corridors of enhanced moisture transport extending for thousands of kilometers, often cause natural disasters over the middle latitudes including East Asia (e.g. , Gimeno et al 2016, Kamae et al 2017c. For example, an AR-like enhanced water vapor transport was closely related to occurrence of the heavy rain event of July 2018 in Japan that caused 221 fatalities due to widespread floods and landslides (Tsuguti et al 2019).…”

Global atmospheric moisture transport associated with precipitation extremes: Mechanisms and climate change impacts

“…ARs are highly related to heavy precipitation, especially the extremely intense precipitation, over western Europe (Lavers & Villarini, ; Pasquier, Pfahl, & Grams, ; Ridder, de Vries, & Drijfhout, ) and western North America (Demaria et al, ; Nayak et al, ; Rutz & Steenburgh, ). ARs also contribute to some extreme precipitation events over regions such as South Africa (Blamey, Ramos, Trigo, Tomé, & Reason, ), East Asian (Kamae, Mei, & Xie, ), and northern Indian (Thapa, Endreny, & Ferguson, ; Yang, Zhao, Ni, & Sun, ), even though other mechanisms triggering regional precipitation dominate (Figure ). ARs contribute to 20–90% of extreme precipitation events during spring, summer, and autumn over East Asia, especially over the Korean Peninsula and Japan with stable low‐level moisture transport and heavy orographic precipitation (Kamae, Mei, & Xie, ).…”

An Expanded Investigation of Atmospheric Rivers in the Southern Appalachian Mountains and Their Connection to Landslides

“…Landslides in the Western U.S. are also more likely to occur in conjunction with ARs on lands affected by wildfires [12]. The importance of ARs has been documented in a variety of climate zones, and across the globe (e.g., References [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]).…”