Meteorological overview and mesoscale characteristics of the Heavy Rain Event of July 2018 in Japan

Consecutive extreme flooding and heat wave in Japan: Are they becoming a norm?

“…The atmospheric features that enhance the ascent and instability of the Baiu rainband have been extensively studied (Sampe and Xie, ); these include the upper‐level westerly jet and traveling synoptic waves, mid‐level advection of warm and moist air influenced by the South Asian thermal low, and low‐level southerly moisture transport associated with an enhanced NPSH. These features are outlined in Figure b as (A) the NPSH, and particularly its western extension; (B) the western Pacific monsoon trough; (C) the South Asian monsoon; (D) the mid‐latitude westerly jet and quasistationary short waves, as well as the Baiu rainband itself; these are based on previous studies (Sampe and Xie, ; JMA‐TCC, ; Tsuguti et al, ). All of these circulation features were observed in the July 2018 heavy precipitation event with an additional presence of Typhoon Prapiroon and a stationary short‐wave trough over Korea (Tsuguti et al, ).…”

“…These features are outlined in Figure b as (A) the NPSH, and particularly its western extension; (B) the western Pacific monsoon trough; (C) the South Asian monsoon; (D) the mid‐latitude westerly jet and quasistationary short waves, as well as the Baiu rainband itself; these are based on previous studies (Sampe and Xie, ; JMA‐TCC, ; Tsuguti et al, ). All of these circulation features were observed in the July 2018 heavy precipitation event with an additional presence of Typhoon Prapiroon and a stationary short‐wave trough over Korea (Tsuguti et al, ). These notable circulation features were present during the heat wave as well (Figure c), while the upper‐level trough was replaced by a short‐wave ridge known to accompany heat waves in Korea and southern Japan (Xu et al, ).…”

“…Death tolls from these two extreme events combined exceeded 300, accompanying tremendous economic losses (BBC: July 24, 2018; AP: July 30, 2018). Meteorological analysis on these 2018 events quickly emerged (JMA‐TCC, ; Kotsuki et al, ; Tsuguti et al, ), highlighting several compound factors: a strengthened subtropical anticyclone, a deepened synoptic trough, and Typhoon Prapiroon that collectively enhanced the Baiu rainband (the Japanese summer monsoon), fostering heavy precipitation. The comprehensive study of these events, conducted within a month and released by the Japan Meteorological Agency (JMA) (JMA‐TCC, ), reflected decades of knowledge of the Baiu rainband and new understanding of recent heat waves in southern Japan and Korea (Xu et al, ).…”

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

“…, 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). Many previous studies have been devoted to investigating future change in AR activity because it is the key for projecting water resources and natural disaster risk.…”

Why We Can No Longer Ignore Consecutive Disasters

“…With $10 billion in damages, this became the second costliest weather event of 2018 (Kornhuber et al, 2019;LeComte, 2019 ;Tsuguti et al, 2019). Subsequently, the flooding caused landslides, which together killed 246 people (LeComte, 2019;Tsuguti et al, 2019). Next, from 14 until 25 July the country was hit by a heatwave, in August several typhoons and tropical storms hit Japan's main island (Typhoon Cimaron made landfall close to Kyoto), and on 4 September Typhoon Jebi struck Japan (Japan Meteorological Agency, 2018;LeComte, 2019;Li et al, 2019).…”