In July 2018, heavy rainfalls occurred throughout the Japanese islands under the influences of Typhoon Prapiroon (2018) and the Baiu frontal activity, and caused extreme river discharge, flooding, and landslides in many places and fatalities of greater than 200, which is the worst disaster in the recent three decades in Japan (Tsuguti et al. 2018). After the heavy rainfall event, record-breaking, extremely hot weather follows (Nishi and Kusaka 2019). About a year before this heavy rainfall event, an extreme rainfall event occurred in the northern part of Kyushu Island, owing to the development of long-lived stationary convective systems, leading to flooding, landslides, and forest damages (Kato et al. 2018; Takemi 2018). The characteristics, maintenance mechanisms, and environmental properties of such linear convective systems and other precipitating systems requires further studies from viewpoints at various temporal and spatial scales. Furthermore, the impacts of climate change on the development of such extreme events should also be considered. In this special edition jointly coordinated with Scientific Online Letters on the Atmosphere (SOLA), we published articles on the extreme rainfall events and other extreme weather that occurred in 2017 and 2018 in Japan, East Asia, and other parts of the world. Here we will overview the articles published in this Special Edition and the Special Edition in SOLA.
Large-scale atmospheric and oceanic characteristics in East Asia, the western North Pacific, and the surrounding regions in summer 2018 were investigated by Liu et al (2019), Shimpo et al. (2019), Sekizawa et al. (2019), Takemura et al. (2019), Takaya (2019), Nishii et al. (2020), and Tseng et al. (2020). Yokoyama et al. (2020) examined the role of an upper-tropospheric trough on the generation of the rainfall event in July 2018.
From a mesoscale point of view, Takemi and Unuma (2019) demonstrated the mesoscale environmental properties of the heavy rainfall event in July 2018. The characteristics and development processes of precipitating systems and their environmental conditions were investigated by Sueki and Kajikawa (2019), Kawano and Kawamura (2020), Hirockawa et al. (2020), Tsuji et al. (2020), Unuma and Takemi (2021), and Ohara et al. (2021). There are a number of studies which investigated the predictability of the heavy rainfall events and extreme weather in the summer of 2018 (Kotsuki et al. 2019; Matsunobu and Matsueda 2019; Kobayashi and Ishikawa 2019). Furthermore, the relationships between a typhoon and the rainfall in July 2018 were examined in Moteki (2019) and Enomoto (2019).
There are studies that focused statistical features of heavy rainfall events. A gridded precipitation product was developed and was used in the analysis of the extreme rainfalls (Yatagai et al. 2019). Nayak and Takemi (2020) examined the Clausius-Clapeyron scaling for the extreme rainfalls in July of 2017 and 2018; this scaling is a key to understand the statistical features of extreme precipitation not only in the present climate but also in a future climate. Extreme weather phenomena were also investigated for cases in Korea (Ha et al. 2020) and in Kazakhstan (Zou et al. 2020).
The impacts of global warming on extreme weather phenomena were also examined. Imada et al. (2019) investigated how the global warming affected the occurrence of the extreme hot summer in 2018 using a large-ensemble climate prediction dataset (Mizuta et al. 2017) and demonstrated the extreme hot event would never have happened without anthropogenic global warming.
Extreme rainfalls and extreme weather appear to occur every year in recent days and their impacts are a serious societal issue. With better understanding on the mechanisms, predictability, and impacts of such extreme events, we should be better prepared for and responded against anticipated disasters from extreme weather.
References
- Enomoto, T., 2019: Influence of the track forecast of Typhoon Prapiroon on the heavy rainfall in western Japan in July 2018. SOLA, 15A, 66-71.
- Ha, K.-J., J.-H. Yeo, Y.-W. Seo, E.-S. Chung, J.-Y. Moon, X. Feng, Y.-W. Lee, and C.-H. Ho, 2020: What caused the extraordinarily hot 2018 summer in Korea? J. Meteor. Soc. Japan, 98, 153-167.
- Hirockawa, Y., T. Kato, H. Tsuguti, and N. Seino, 2020: Identification and classification of heavy rainfall areas and their characteristic features in Japan. J. Meteor. Soc. Japan, 98, 835-857.
- Imada, Y., M. Watanabe, H. Kawase, H. Shiogama, and M. Arai, 2019: The July 2018 high temperature event in Japan could not have happened without human-induced global warming. SOLA, 15A, 8-12.
- Kato, R., K. Shimose, and S. Shimizu, 2018: Predictability of precipitation caused by linear precipitation systems during the July 2017 Northern Kyushu Heavy Rainfall Event using a cloud-resolving numerical weather prediction model. J. Disas. Res., 13, 846-859.
- Kawano, T., and R. Kawamura, 2020: Genesis and maintenance processes of a quasi-stationary convective band that produced record-breaking precipitation in northern Kyushu, Japan on 5 July 2017. J. Meteor. Soc. Japan, 98, 673-690.
- Kobayashi, C., and I. Ishikawa, 2019: Prolonged northern-mid-latitude tropospheric warming in 2018 well predicted by the JMA operational seasonal prediction system. SOLA, 15A, 31-36.
- Kotsuki, S., K. Terasaki, K. Kanemaru, M. Satoh, T. Kubota, and T. Miyoshi, 2019: Predictability of record-breaking rainfall in Japan in July 2018: Ensemble forecast experiments with the near-real-time global atmospheric data assimilation system NEXRA. SOLA, 15A, 1-7.
- Liu, B., C. Zhu, J. Su, S. Ma, and K. Xu, 2019: Record-breaking northward shift of the western North Pacific Subtropical High in July 2018. J. Meteor. Soc. Japan, 97, 913-925.
- Matsunobu, T., and M. Matsueda, 2019: Assessing the predictability of heavy rainfall events in Japan in early July 2018 on medium-range timescales. SOLA, 15A, 19-24.
- Mizuta, R., A. Murata, M. Ishii, H. Shiogama, K. Hibino, N. Mori, O. Arakawa, Y. Imada, K. Yoshida, T. Aoyagi, H. Kawase, M. Mori, Y. Okada, T. Shimura, T. Nagatomo, M. Ikeda, H. Endo, M. Nosaka, M. Arai, C. Takahashi, K. Tanaka, T. Takemi, Y. Tachikawa, K. Temur, Y. Kamae, M. Watanabe, H. Sasaki, A. Kitoh, I. Takayabu, E. Nakakita, and M. Kimoto, 2017: Over 5000 years of ensemble future climate simulations by 60 km global and 20 km regional atmospheric models. Bull. Amer. Meteor. Soc., 98, 1383-1398.
- Moteki, Q., 2019: Role of Typhoon Prapiroon (Typhoon No. 7) on the formation process of the Baiu front inducing heavy rain in July 2018 in western Japan. SOLA, 15A, 37-42.
- Nayak, S., and T. Takemi, 2020: Clausius-Clapeyron scaling of extremely heavy precipitations: Case studies of the July 2017 and July 2018 heavy rainfall events over Japan. J. Meteor. Soc. Japan, 98, 1147-1162
- Nishi, A., and H. Kusaka, 2019: Effect of foehn wind on record-breaking high temperature event (41.1°C) at Kumagaya on 23 July 2018. SOLA, 15, 17-21.
- Nishii, K., B. Taguchi, and H. Nakamura, 2020: An atmospheric general circulation model assessment of oceanic impacts on extreme climate events over Japan in July 2018. J. Meteor. Soc. Japan, 98, 801-820.
- Ohara, R., T. Iwasaki, and T. Yamazaki, 2021: Impacts of Evaporative Cooling from Raindrops on the Frontal Heavy Rainfall Formation over Western Japan on 5–8 July 2018. J. Meteor. Soc. Japan, 99, 1351-1369.
- Sekizawa, S., T. Miyasaka, H. Nakamura, A. Shimpo, K. Takemura, and S. Maeda, 2019: Anomalous moisture transport and oceanic evaporation during a torrential rainfall event over western Japan in early July 2018. SOLA, 15A, 25-30.
- Shimpo, A., K. Takemura, S. Wakamatsu, H. Togawa, Y. Mochizuki, M. Takekawa, S. Tanaka, K. Yamashita, S. Maeda, R. Kurora, H. Murai, N. Kitabatake, H. Tsuguti, H. Mukou gawa, T. Iwasaki, R. Kawamura, M. Kimoto, I. Takayabu, Y. N. Takayabu, Y. Tanimoto, T. Hirooka, Y. Masumoto, M. Watanabe, K. Tsuboki, and H. Nakamura, 2019: Primary factors behind the Heavy Rain Event of July 2018 and the subsequent heat wave in Japan. SOLA, 15A, 13-18.
- Sueki, K., and Y. Kajikawa, 2019: Different precipitation systems between Hiroshima and Keihanshin during extreme rainfall event in western Japan in July 2018. J. Meteor. Soc. Japan, 97, 1221-1232.
- Takaya, Y., 2019: Positive phase of Pacific meridional mode enhanced western North Pacific tropical cyclone activity in summer 2018. SOLA, 15A, 55-59.
- Takemi, T., 2018: Importance of terrain representation in simulating a stationary convective system for the July 2017 Northern Kyushu Heavy Rainfall case. SOLA, 14, 153-158.
- Takemi, T., and T. Unuma, 2019: Diagnosing environmental properties of the July 2018 Heavy Rainfall Event in Japan. SOLA, 15A, 60-65.
- Takemura, K., S. Wakamatsu, H. Togawa, A. Shimpo, C. Kobayashi, S. Maeda, and H. Nakamura, 2019: Extreme moisture flux convergence over western Japan during the Heavy Rain Event of July 2018. SOLA, 15A, 49-54.
- Tseng, W.-L., C.-C. Hong, M.-Y. Lee, H.-H. Hsu, and C.-C. Chang, 2020: Compound effect of local and remote sea surface temperature on the unusual 2018 western North Pacific summer monsoon. J. Meteor. Soc. Japan, 98, 1369-1385.
- Tsuguti, H., N. Seino, H. Kawase, Y. Imada, T. Nakaegawa, and I. Takayabu, 2018: Meteorological overview and mesoscale characteristics of the Heavy Rain Event of July 2018 in Japan. Landslides, 16, 363-371.
- Tsuji, H., C. Yokoyama, and Y. N. Takayabu, 2020: Contrasting features of the July 2018 heavy rainfall event and the 2017 Northern Kyushu rainfall event in Japan. J. Meteor. Soc. Japan, 98, 859-876.
- Unuma, T., and T. Takemi, 2021: Rainfall characteristics and their environmental conditions during the heavy rainfall events over Japan in July of 2017 and 2018. J. Meteor. Soc. Japan, 99, 165-180.
- Yatagai, A., K. Minami, M. Masuda, and N. Sueto, 2019: Development of intensive APHRODITE hourly precipitation data for assessment of the moisture transport that caused heavy precipitation events. SOLA, 15A, 43-48.
- Yokoyama, C., H. Tsuji, and Y. N. Takayabu, 2020: The effects of an upper-tropospheric trough on the heavy rainfall event in July 2018 over Japan. J. Meteor. Soc. Japan, 98, 235-255.
- Zou, S., J. Abuduwaili, J. Ding, W. Duan, P. De Maeyer, and T. Van de Voorde, 2020: Description and attribution analysis of the 2017 spring anomalous high temperature causing floods in Kazakhstan. J. Meteor. Soc. Japan, 98, 1353-1368.
