Characteristics of Atmospheric Environments of Quasi-Stationary Convective Bands in Kyushu, Japan during the July 2020 Heavy Rainfall Event

This study investigated characteristics of atmospheric envi- ronmental fields in the occurrence of quasi-stationary convective bands (QSCBs) in Kyushu, western Japan during the July 2020 heavy rainfall event. We performed case studies of extreme rainfall subevents in the Kumamoto and Kagoshima prefectures on 3−4 July (2020KK) and northern Kyushu on 6−7 July 2020 (2020NK), compared with two heavy rainfall events in northern Kyushu in 2017 and 2018. Nine QSCBs were objectively extracted during the July 2020 heavy rainfall event, causing hourly precipitation amounts exceeding 100 mm twenty times. In 2020KK, the environmental field with extremely large precipitable water due to low-level and mid-dle-level humidity was affected by the upper-level cold airflow, which resulted in favorable condition for the deep convection development. Consequently, the lightning activity became high, and cloud tops were the highest in comparison to previous events. QSCBs in 2020KK and 2020NK were located along a low-level convergence line/zone associated with an inflow that had extreme ly large water vapor flux on the south side of the mesoscale Baiu frontal depressions. In most of the QSCB cases in 2020, mesoscale depressions were observed and enhanced horizontal winds, which led to extremely large low-level water vapor flux to produce short-term heavy rainfall. ( Characteristics of atmospheric environments of quasi- stationary convective bands in Kyushu, Japan during the July 2020 heavy rain fall event. in Kumamoto and Kagoshima prefectures on 3−4 July (2020KK) and northern Kyushu on 6−7 July 2020 (2020NK), comparing them with the extreme rainfall events on 6−7 July 2018 (2018NK) and on 5 July 2017 (2017NK) focusing on the importance of mesoscale BFDs using environmental parameters derived from analysis data.

[1]  T. Kato,et al.  Characteristics of an Extreme Rainfall Event in Kyushu District, Southwestern Japan in Early July 2020 , 2020 .

[2]  Y. Takayabu,et al.  Contrasting Features of the July 2018 Heavy Rainfall Event and the 2017 Northern Kyushu Rainfall Event in Japan , 2020, Journal of the Meteorological Society of Japan. Ser. II.

[3]  T. Kato,et al.  Identification and Classification of Heavy Rainfall Areas and their Characteristic Features in Japan , 2020, Journal of the Meteorological Society of Japan. Ser. II.

[4]  T. Kawano,et al.  Genesis and Maintenance Processes of a Quasi-stationary Convective Band that Produced Record-Breaking Precipitation in Northern Kyushu, Japan on 5 July 2017 , 2020, Journal of the Meteorological Society of Japan. Ser. II.

[5]  T. Kato.  Quasi-stationary Band-Shaped Precipitation Systems, Named “Senjo-Kousuitai”, Causing Localized Heavy Rainfall in Japan , 2020 .

[6]  T. Takemi,et al.  Diagnosing Environmental Properties of the July 2018 Heavy Rainfall Event in Japan , 2019, SOLA.

[7]  C. Kobayashi,et al.  Extreme Moisture Flux Convergence over Western Japan during the Heavy Rain Event of July 2018 , 2019, SOLA.

[8]  A. Yatagai,et al.  Development of Intensive APHRODITE Hourly Precipitation Data for Assessment of the Moisture Transport That Caused Heavy Precipitation Events , 2019, SOLA.

[9]  H. Nakamura,et al.  Anomalous Moisture Transport and Oceanic Evaporation during a Torrential Rainfall Event over Western Japan in Early July 2018 , 2019, SOLA.

[10]  Izuru Takayabu,et al.  Meteorological overview and mesoscale characteristics of the Heavy Rain Event of July 2018 in Japan , 2018, Landslides.

[11]  Ken-ichi Shimose,et al.  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 , 2018, Journal of Disaster Research.

[12]  T. Takemi.  Importance of terrain representation in simulating a stationary convective system for the July 2017 Northern Kyushu Heavy Rainfall case , 2018 .

[13]  S. Xie,et al.  Climatological Relationship between Warm Season Atmospheric Rivers and Heavy Rainfall over East Asia , 2017 .

[14]  T. Kawano,et al.  Numerical Investigation of Development Processes of Baiu Frontal Depressions Part I: Case Studies , 2017 .

[15]  Tetsuya Takemi,et al.  Characteristics and environmental conditions of quasi‐stationary convective clusters during the warm season in Japan , 2016 .

[16]  T. Kato,et al.  Objective Extraction of Heavy Rainfall Events and Statistical Analysis on their Characteristic Features , 2014 .

[17]  T. Kato.  HEAVY RAINFALL OVER THE BAIU FRONTAL ZONE AROUND JAPAN — RELATION WITH CLOUD TOP HEIGHTS OF CUMULONIMBI , 2011 .

[18]  T. Kato,et al.  Statistical Study on Cloud Top Heights of Cumulonimbi Thermodynamically Estimated from Objective Analysis Data during the Baiu Season , 2007 .

[19]  T. Kato.  Structure of the Band-Shaped Precipitation System Inducing the Heavy Rainfall Observed over Northern Kyushu, Japan on 29 June 1999 , 2006 .

[20]  T. Kato.  Statistical Study of Band-Shaped Rainfall Systems, the Koshikijima and Nagasaki Lines, Observed around Kyushu Island, Japan , 2005 .

[21]  T. Kato,et al.  Structure and Development of Two Merged Rainbands Observed over the East China Sea during X-BAIU-99 Part I: Meso-β-Scale Structure and Development Processes , 2004 .

[22]  T. Kato,et al.  Structure and Development of Two Merged Rainbands Observed over the East China Sea during X-BAIU-99 : Part II: Meso-α-Scale Structure and Build-up Processes of Convergence in the Baiu Frontal Region , 2004 .

[23]  T. Kato,et al.  Reason for the Failure of the Simulation of Heavy Rainfall during X-BAIU-01-Importance of a Vertical Profile of Water Vapor for Numerical Simulations- , 2003 .

[24]  H. Takayama,et al.  Analytical and numerical study of the 26 June 1998 orographic rainband observed in Western Kyushu, Japan , 2000 .

[25]  K. Ninomiya.  1991年7月1〜10日の強い降雨を伴う梅雨前線の大規模及びメソ-α-規模の様相 , 2000 .

[26]  Richard L. Thompson,et al.  Predicting Supercell Motion Using a New Hodograph Technique , 2000 .

[27]  T. Kato.  Numerical Simulation of the Band-shaped Torrential Rain Observed over Southern Kyushu, Japan on 1 August 1993 , 1998 .

[28]  Y. Ogura,et al.  A Modeling Case Study of Interaction between Heavy Precipitation and a Low-Level Jet over Japan in the Baiu Season , 1991 .

[29]  Howard B. Bluestein,et al.  Formation of Mesoscale Lines of Pirecipitation: Severe Squall Lines in Oklahoma during the Spring , 1985 .

[30]  Robert A. Maddox,et al.  An Evaluation of Tornado Proximity Wind and Stability Data , 1976 .

[31]  Y. Takayabu,et al.  The Effects of an Upper-Tropospheric Trough on the Heavy Rainfall Event in July 2018 over Japan , 2020 .

[32]  Misako Kachi,et al.  Global Satellite Mapping of Precipitation (GSMaP) Products in the GPM Era , 2020 .

[33]  Y. Masumoto,et al.  Primary Factors behind the Heavy Rain Event of July 2018 and the Subsequent Heat Wave in Japan , 2019, SOLA.

[34]  T. Kato.  Representative Height of the Low-Level Water Vapor Field for Examining the Initiation of Moist Convection Leading to Heavy Rainfall in East Asia , 2018 .

[35]  Kato Teruyuki,et al.  Analysis of Atmospheric Environments for Convective Cloud Development around the Central Mountains in Japan during Warm Seasons Using Ground-Based Microwave Radiometer Data , 2017 .

[36]  A. Okuyama,et al.  An Introduction to Himawari-8/9— Japan’s New-Generation Geostationary Meteorological Satellites , 2016 .

[37]  T. Takemi,et al.  A Role of Environmental Shear on the Organization Mode of Quasi-Stationary Convective Clusters during the Warm Season in Japan , 2016 .

[38]  T. Kawano,et al.  Development Processes of Baiu Frontal Depressions , 2012 .

[39]  Kazuhiko Nagata.  Quantitative Precipitation Estimation and Quantitative Precipitation Forecasting by the Japan Meteorological Agency , 2011 .

[40]  Y. Ogura,et al.  A case study of a heavy precipitation event along the Baiu front in northern Kyushu, 23 July 1982: Nagasaki heavy rainfall , 1985 .

[41]  K. Ninomiya,et al.  Prediction Experiment of Extremely Intense Rainstorm by a Very-Fine Mesh Primitive Equation Model , 1984 .

[42]  T. Akiyama.  A Medium-Scale Cloud Cluster in a Baiu Front: Part I: Evolution Process and Fine Structure@@@第1部発達過程と微細構造 , 1984 .

[43]  K. Ninomiya,et al.  Heavy Rainfalls Associated With Frontal Depression in Asian Subtropical Humid Region (II) Mesoscale Features of Precipitation, Radar Echoes and Stratification , 1979 .

[44]  K. Ninomiya.  Heavy Rainfalls Associated with Frontal Depression in Asian Subtropical Humid Region , 1978 .

[45]  気象庁.  Outline of the operational numerical weather prediction at the Japan Meteorological Agency , 1977 .

[46]  T. Akiyama.  The Large-Scale Aspects of the Characteristic Features of the Baiu Front: With Special Emphasis on the Relation Among the Ageostrophic Low-level Jet Stream, Moist Tongue, Convective Warming, Convergence Zone within Baiu Front and Heavy Rainfall@@@特に,前線内の非地衡風的な下層jet,湿舌,対流昇温,収束帯および豪雨との関連に重点を於いて , 1973 .