Precipitation Characteristics over East Asia in Early Summer: Effects of the Subtropical Jet and Lower-Tropospheric Convective Instability

Yokoyama, Chie; Takayabu, Yukari N.; Horinouchi, Takeshi

doi:10.1175/jcli-d-16-0724.1

Cited by 29 publications

(33 citation statements)

References 42 publications

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“…According to Yokoyama et al (2017) Previous studies have shown that mid-tropospheric moisture is an important factor in the development of deep cumulus convection and its organization (e.g., Sherwood 1999;Kuang and Bretherton 2006;Takayabu et al 2010;Yokoyama et al 2017). We emphasize that the moistening of the mid-troposphere at around 650 hPa during the heavy rainfall event was caused not only by diabatically-generated ascent but by dynamically-forced ascent.…”

Section: Discussionmentioning

confidence: 88%

“…This is also consistent with Nie and Fan (2019)'s study on extreme rainfall events in the dynamical forcing-diabatic feedback perspective. Yokoyama et al (2017) showed that in the baiu season, the subtropical jet has an effect on moistening of the mid-troposphere owing to dynamically-forced ascent to the south of the subtropical jet, especially around the jet entrance, producing environments favorable for the organization of rainfall. In the heavy rainfall event in July 2018, the subtropical jet accelerated on the front of the upper-tropospheric trough (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that generation of cumulus congestus is well determined by sea surface temperature (Takayabu et al 2010) and convective instability in the lower troposphere (Yokoyama et al 2017). Rainfall is scarcely produced where the lower-tropospheric convective stability is strong.…”

Section: Differences In Rainfall-environment Relationships Among Regionsmentioning

confidence: 99%

“…Note that the secondary circulation is characterized by upwelling and downwelling to the south and north of the subtropical jet, respectively. Yokoyama et al (2017) showed that the subtropical jet plays a role in moistening the mid-troposphere during the baiu season. They found that dynamical ascent associated with the secondary circulation to the south of the jet produces environments favorable for the organization of rainfall.…”

Section: Backgroundsmentioning

confidence: 99%

“…As shown in the previous section, we observe a free troposphere with very high moisture content over a wide area of Japan during the heavy rainfall event, suggesting that there is a mechanism capable of maintaining such extensive humidity stratification. Yokoyama et al (2017) showed that large-scale, dynamically-forced ascent promotes the generation of organized rainfall systems through the moistening of the mid-troposphere during the baiu season. Here, the effects of an upper-tropospheric narrow, deep trough on the rear of the heavy rainfall area on free-tropospheric humidity are explored in detail.…”

Section: Effects Of Dynamically-forced Ascent Associated With An Uppementioning

confidence: 99%

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The Effects of an Upper-Tropospheric Trough on the Heavy Rainfall Event in July 2018 over Japan

Yokoyama

Tsuji

Takayabu

2020

Journal of the Meteorological Society of Japan

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In this study, we examined the characteristics of a rainfall system that brought heavy rainfall to a broad portion of western Japan on July 5-8, 2018 and the role played by an upper-tropospheric trough which stayed to the rear of the extensive rainfall area during the event. The Dual-frequency Precipitation Radar onboard the core satellite of the Global Precipitation Measurement revealed the significant contribution of rainfall with its top below 10 km, the broad spatial extent covered by stratiform rainfall, and the presence of convective rainfall embedded in the large stratiform rainfall area. These features are characteristic of well-organized rainfall systems. Based on the analysis of meteorological data, large-scale environmental conditions related to the event were found to be relatively stable and very humid throughout most of the troposphere, compared to the climatology. This large-scale environment, which is consistent with previous statistical results for extreme rainfall events, was present across an extensive area of Japan. We found that the trough played an important role in maintaining an environment favorable for the organization of rainfall. Dynamical ascent associated with the trough acted to produce vertical moisture flux convergence in the mid-troposphere and upper troposphere, and moistened most of the troposphere in conjunction with horizontal moisture flux convergence. Humid conditions in the mid-to lower troposphere enhanced the development of deep convection when the lower troposphere was convectively unstable. Once deep convection was promoted in this way, convection itself could moisten the mid-to upper troposphere further through diabatic ascent, thereby loading the free troposphere with moisture. This synergy between the dynamical effect and the diabatic effect enhanced the conditions that allowed for a well-organized rainfall system that produced very heavy rainfall over a large portion of Japan.

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Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Differences In Rainfall-environment Relationships Among Regionsmentioning

confidence: 99%

Section: Backgroundsmentioning

confidence: 99%

Section: Effects Of Dynamically-forced Ascent Associated With An Uppementioning

confidence: 99%

See 3 more Smart Citations

The Effects of an Upper-Tropospheric Trough on the Heavy Rainfall Event in July 2018 over Japan

Yokoyama

Tsuji

Takayabu

2020

Journal of the Meteorological Society of Japan

Self Cite

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A Lagrangian view of moisture transport related to the heavy rainfall of July 2020 in Japan: Importance of the moistening over the subtropical regions

Zhao

Manda

Guo

et al. 2020

Preprint

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Extremely heavy rain fell over Japan in July 2020 (hereafter, 20HR). The rainfall continued during this whole period and included several severe rainfall events. As reported by the Japan Meteorological Agency (JMA), during this event, the 48 h precipitation exceeded 1,300 mm in many regions of western Japan (e.g., Kyushu, Gifu, Kochi, and Nagano). Specifically, some records indicate that the total precipitation was equal to nearly half of the historical annual mean (e.g., Fukuoka, Kagoshima; JMA, 2020). It was reported that 82 fatalities occurred, and 18,380 buildings were destroyed or damaged during the heavy rains (EOCJ, 2020). Kamae (2020), based on a series of early analyses, showed that a narrow plume of water vapor transport (.e., the atmospheric river, AR; also see Figure 1a) played a key role in 20HR. According to the results in Kamae (2020) and JMA (2020), this AR started from the South China Sea (SCS) and passed through the southeast China mainland, before turning west along the Baiu front. It was also reinforced by the low-level flows from the south, similar to previous events in Japan (e.g., Hirota et al., 2016;Tsuguti et al., 2019). Meanwhile, it is likely that the westward extension of the western Pacific Subtropical High (WPSH) also enhanced the northward moisture transport from the SCS to Japan (e.g., Naoi et al., 2020).To date, the relationship between moisture transport and heavy rainfall during the Baiu season has been extensively studied (e.g.,

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Long‐term change of summer mean and extreme precipitations in Korea and East Asia

Kim

Cha

et al. 2023

Intl Journal of Climatology

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The change of the precipitation characteristics over South Korea is investigated using long‐term (60 years) hourly precipitation records from surface stations focusing on extended summer (June–September) and rainy season (Changma). The precipitation characteristics including extreme events (>30 mm·h−1 or >100 mm·day−1) are also compared for the past (1961–1990) and recent (1991–2020) climatology. The amount of summer precipitation shows a notable increase over South Korea (2.6 mm·day−1·century−1) during the last 60 years (1961–2020) although it is smaller than recent 48‐year trend measured in North Korea (9.7 mm·day−1·century−1). Precipitation amounts are significantly increased than past climatology particularly in 70–100 and 200 mm·day−1 intensity ranges. The frequency of extreme precipitation also exhibits an increasing trend (1.0 frequency·century−1) during the last 60 years over South Korea. The frequency of extreme precipitation has been doubled in the recent climatology compared to the past climatology. Daily precipitations in top 1 percentile present clear increasing trends during the extended summer and Changma season in South Korea. Further investigation using gridded precipitation reveals that the similar mean and extreme precipitation increases are observed over the wider regions in East Asia, including central China and southern Japan. This result implies that the long‐term precipitation change over South Korea is related to a large‐scale circulation change in the East Asian summer monsoon.

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Precipitation Characteristics over East Asia in Early Summer: Effects of the Subtropical Jet and Lower-Tropospheric Convective Instability

Cited by 29 publications

References 42 publications

The Effects of an Upper-Tropospheric Trough on the Heavy Rainfall Event in July 2018 over Japan

The Effects of an Upper-Tropospheric Trough on the Heavy Rainfall Event in July 2018 over Japan

A Lagrangian view of moisture transport related to the heavy rainfall of July 2020 in Japan: Importance of the moistening over the subtropical regions

Long‐term change of summer mean and extreme precipitations in Korea and East Asia

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