A 1024-Member NICAM-LETKF Experiment for the July 2020 Heavy Rainfall Event

Terasaki, Koji; Miyoshi, Takemasa

doi:10.2151/sola.18a-002

Cited by 5 publications

(2 citation statements)

References 18 publications

(12 reference statements)

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“…In addition, the 7-day mean precipitation and moisture ux convergence over Kyushu were the greatest over the last 40 and 30 years, respectively. From the perspective of heavy rainfall forecasting, Terasaki and Miyoshi (2022) demonstrated that with the use of a 54-km horizontal resolution and 1024 member ensemble forecasts, the probability of heavy rainfall in Kyushu could be captured approximately ve days before the extreme rainfall disaster in Kumamoto Prefecture occurred on 4 July. Moreover, air-sea interaction processes played a signi cant role in the precipitation peak during the latter half of July in 2020.…”

Section: Introductionmentioning

confidence: 99%

Factors Affecting the Stagnation of the Baiu Front that Induced Heavy Rainfall in July 2020 over Kyushu, Japan

Moteki

2023

Preprint

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In this paper, the influencing factors of the long-term stagnation of the Baiu front that induced heavy rainfall in July 2020 over Kyushu, Japan, were examined. The position of the Baiu front was determined from a weather chart at 130°E. The front remained stationary between 30 and 35°N for 20 days in July 2020. The number of total days of Baiu front stagnation was the largest from 2002–2021. By examining a certain index of the Yellow Sea High (YSH), which is a necessary condition for Baiu front stagnation near Kyushu, it was confirmed that in 2020, a positive high-pressure anomaly persisted over the Yellow Sea until the end of July. The observed YSH maintenance was potentially due to the negative sea surface temperature (SST) anomaly over the Yellow Sea throughout July 2020. In addition, the impact of extratropical cyclones passing at the end of June was suggested as a factor of the occurrence of significant negative SST anomalies in the Yellow Sea. With the passage of a strong extratropical cyclone through the central part of the Yellow Sea from June 29–30 in 2020, a rapid SST decrease ranging from 0.5–1.5°C/day was caused by ocean mixed layer deepening. This rapid SST decreasing process was repeated 3 times on 13, 19, and 24 July. As a result, a notable SST contrast was maintained at approximately 30°N because the SST difference between the Kuroshio Current and the Yellow Sea remained large throughout July 2020. The notable contrasts in the SST and surface air temperature (SAT) coincided well with YSH maintenance over the sea west of Kyushu and could contribute to long-term stagnation of the Baiu front.

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Section: Introductionmentioning

confidence: 99%

Factors Affecting the Stagnation of the Baiu Front that Induced Heavy Rainfall in July 2020 over Kyushu, Japan

Moteki

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…In addition, the 7-day mean precipitation and moisture flux convergence over Kyushu were the greatest over the last 40 and 30 years, respectively. From the perspective of heavy rainfall forecasting, Terasaki and Miyoshi 7 demonstrated that with the use of 54-km horizontal resolution and 1024 member ensemble forecasts, the probability of heavy rainfall in Kyushu could be captured approximately 5 days before the extreme rainfall disaster in Kumamoto Prefecture occurred on 4 July.…”

Section: Introductionmentioning

confidence: 99%

Influencing factors in the stagnation of the Baiu front that induced heavy rainfall in July 2020 over Kyushu, Japan

Moteki

2023

Sci Rep

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The influencing factors of the long-term stagnation of the Baiu front that induced heavy rainfall in July 2020 over Kyushu, Japan, were examined. In July 2020, the position of the Baiu front from a weather chart at 130° E remained stationary over Kyushu for 20 days, and that was the longest from 2002 to 2021. By examining a certain index of the Yellow Sea High (YSH), which is a necessary condition for Baiu front stagnation near Kyushu, it was confirmed that in 2020, a positive high-pressure anomaly persisted over the Yellow Sea until the end of July. The YSH maintenance was due to the significant negative sea surface temperature (SST) anomaly over the Yellow Sea. The significant negative SST anomalies in the Yellow Sea were due to vertical mixing in ocean mixed layer in response to the strong winds of the extratropical cyclones. A rapid SST decrease ranging from 0.5 to 1.5 °C/day was repeatedly occurred by ocean mixed layer deepening in association with the passage of the extratropical cyclones. The anomalous long-term stagnation of YSH due to the negative SST anomalies could have caused the Baiu front to remain stagnant over Kyushu until the end of July.

show abstract

Influencing Factors in the Stagnation of the Baiu Front that Induced Heavy Rainfall in July 2020 over Kyushu, Japan

Moteki

2023

Preprint

View full text Add to dashboard Cite

The influencing factors of the long-term stagnation of the Baiu front that induced heavy rainfall in July 2020 over Kyushu, Japan, were examined. In July 2020, the position of the Baiu front from a weather chart at 130°E remained stationary over Kyushu for 20 days, and that was the longest from 2002–2021. By examining a certain index of the Yellow Sea High (YSH), which is a necessary condition for Baiu front stagnation near Kyushu, it was confirmed that in 2020, a positive high-pressure anomaly persisted over the Yellow Sea until the end of July. The YSH maintenance was due to the significant negative sea surface temperature (SST) anomaly over the Yellow Sea. The significant negative SST anomalies in the Yellow Sea were due to vertical mixing in ocean mixed layer in response to the strong winds of the extratropical cyclones. A rapid SST decrease ranging from 0.5–1.5°C/day was repeatedly occurred by ocean mixed layer deepening in association with the passage of the extratropical cyclones. The anomalous long-term stagnation of YSH due to the negative SST anomalies could have caused the Baiu front to remain stagnant over Kyushu until the end of July.

show abstract

A 1024-Member NICAM-LETKF Experiment for the July 2020 Heavy Rainfall Event

Cited by 5 publications

References 18 publications

Factors Affecting the Stagnation of the Baiu Front that Induced Heavy Rainfall in July 2020 over Kyushu, Japan

Factors Affecting the Stagnation of the Baiu Front that Induced Heavy Rainfall in July 2020 over Kyushu, Japan

Influencing factors in the stagnation of the Baiu front that induced heavy rainfall in July 2020 over Kyushu, Japan

Influencing Factors in the Stagnation of the Baiu Front that Induced Heavy Rainfall in July 2020 over Kyushu, Japan

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