著者
Shion Sekizawa Takafumi Miyasaka Hisashi Nakamura Akihiko Shimpo Kazuto Takemura Shuhei Maeda
出版者
Meteorological Society of Japan
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
pp.15A-005, (Released:2019-05-22)
被引用文献数
14

During a torrential rainfall event in early July 2018, profound enhancement of moisture influx from the south and its convergence occurred over western Japan, which is investigated in this study on the basis of objective analysis and forecast data from the Japan Meteorological Agency Meso-Scale Model. The heavy rainfall over western Japan is found to accompany enhanced oceanic evaporation extensively around Japan, especially around the Kuroshio and entirely over the Sea of Japan. Linear decompositions of the anomalous moisture flux and surface latent heat flux anomalies applied to the high-resolution data reveals that the intensified speed of the low-level southerlies was the primary factor for the pronounced enhancement of both the moisture transport into the heavy rainfall region, especially in its western portion, and evaporation around the Kuroshio into the southerlies. An additional contribution is found from positive sea-surface temperature anomalies to the enhanced southerly moisture inflow into the eastern portion of the rainfall region. These findings have been confirmed through a backward trajectory analysis, which suggests that anomalous moisture supply to air parcels into the rainfall region primarily through the enhanced wind-forced evaporation roughly corresponds to about 10% of the precipitable water anomaly over western Japan.
著者
Shion Sekizawa Takafumi Miyasaka Hisashi Nakamura Akihiko Shimpo Kazuto Takemura Shuhei Maeda
出版者
Meteorological Society of Japan
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
vol.15A, pp.25-30, 2019 (Released:2019-06-22)
参考文献数
10
被引用文献数
14

During a torrential rainfall event in early July 2018, profound enhancement of moisture influx from the south and its convergence occurred over western Japan, which is investigated in this study on the basis of objective analysis and forecast data from the Japan Meteorological Agency Meso-Scale Model. The heavy rainfall over western Japan is found to accompany enhanced oceanic evaporation extensively around Japan, especially around the Kuroshio and entirely over the Sea of Japan. Linear decompositions of the anomalous moisture flux and surface latent heat flux anomalies applied to the high-resolution data reveal that the intensified speed of the low-level southerlies was the primary factor for the pronounced enhancement of both the moisture transport into the heavy rainfall region, especially in its western portion, and evaporation around the Kuroshio into the southerlies. An additional contribution is found from positive sea-surface temperature anomalies to the enhanced southerly moisture inflow into the eastern portion of the rainfall region. These findings have been confirmed through a backward trajectory analysis, which suggests that anomalous moisture supply to air parcels into the rainfall region primarily through the enhanced wind-forced evaporation roughly corresponds to about 10% of the precipitable water anomaly over western Japan.
著者
Hiroaki Kawase Munehiko Yamaguchi Yukiko Imada Syugo Hayashi Akihiko Murata Tosiyuki Nakaegawa Takafumi Miyasaka Izuru Takayabu
出版者
Meteorological Society of Japan
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
vol.17A, no.Special_Edition, pp.7-13, 2021 (Released:2021-01-28)
参考文献数
34

Impacts of historical warming on extremely heavy rainfall induced by Typhoon Hagibis (2019) are investigated using a storyline event attribution approach with the Japan Meteorological Agency Nonhydrostatic Model (JMA-NHM). Control experiments based on JMA mesoscale analysis data well reproduce the typhoon's track, intensity, and heavy precipitation. First, two non-warming experiments are conducted: One excludes both 40-year atmospheric and oceanic temperature trends from 1980 to 2019, and the other excludes the oceanic trend only. A comparison between control and non-warming experiments indicates that historical warming strengthens typhoons and increases the amount of total precipitation by 10.9% over central Japan. The difference between CTL and non-warming experiments without both atmospheric and oceanic temperature trends is larger than that without just the oceanic trend (7.3%). Additional sensitivity experiments without Japan's topography indicate that topography enhances not only total precipitation but also the changes in total precipitation due to historical warming. Through the storyline event attribution approach, it is concluded that historical warming intensifies strength of Typhoon Hagibis (2019) and enhances the extremely heavy precipitation induced by the typhoon.
著者
Takafumi Miyasaka Hiroaki Kawase Tosiyuki Nakaegawa Yukiko Imada Izuru Takayabu
出版者
Meteorological Society of Japan
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
vol.16, pp.125-131, 2020 (Released:2020-07-23)
参考文献数
25
被引用文献数
1

Heavy precipitation in Japan is caused by various phenomena, such as tropical cyclones and the Baiu front, and shows regional-scale variation. Here we investigate extremely heavy precipitation events exceeding the 100-year return period in the Kanto area and future projections of such events using large ensemble climate simulations for periods of several thousand years. To understand these extreme events, associated sea level pressure anomalies over Japan and the surrounding region are classified into four clusters. These cluster means are characterized by (1) a strong anomalous cyclone, (2) a weak anomalous cyclone, (3) an anomalous cyclone accompanied by an anomalous anticyclone to the north, and (4) an anomalous anticyclone to the north. The cluster with a strong anomalous cyclone is accompanied by widely distributed heavy precipitation, and its area-averaged precipitation is predicted to be more enhanced under global warming than that of other clusters, partly because of an increase in the strength of strong tropical cyclones approaching Kanto. The cluster dominated by an anomalous anticyclone is characterized by localized heavy precipitation in the plains area. The relative frequency of this cluster will increase, whereas that of other clusters will decrease under global warming.
著者
Takafumi Miyasaka Hiroaki Kawase Tosiyuki Nakaegawa Yukiko Imada Izuru Takayabu
出版者
Meteorological Society of Japan
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
pp.2020-022, (Released:2020-06-22)
被引用文献数
1

Heavy precipitation in Japan is caused by various phenomena, such as tropical cyclones and the Baiu front, and shows regional-scale variation. Here we investigate extremely heavy precipitation events exceeding the 100-year return period in the Kanto area and future projections of such events using large ensemble climate simulations for periods of several thousand years. To understand these extreme events, associated sea level pressure anomalies over Japan and the surrounding region are classified into four clusters. These cluster means are characterized by (1) a strong anomalous cyclone, (2) a weak anomalous cyclone, (3) an anomalous cyclone accompanied by an anomalous anticyclone to the north, and (4) an anomalous anticyclone to the north. The cluster with a strong anomalous cyclone is accompanied by widely distributed heavy precipitation, and its area-averaged precipitation is predicted to be more enhanced under global warming than that of other clusters, partly because of an increase in the strength of strong tropical cyclones approaching Kanto. The cluster dominated by an anomalous anticyclone is characterized by localized heavy precipitation in the plains area. The relative frequency of this cluster will increase, whereas that of other clusters will decrease under global warming.
著者
Kazuaki NISHII Takafumi MIYASAKA Yu KOSAKA Hisashi NAKAMURA
出版者
Meteorological Society of Japan
雑誌
気象集誌. 第2輯 (ISSN:00261165)
巻号頁・発行日
vol.87, no.3, pp.581-588, 2009 (Released:2009-07-08)
参考文献数
17
被引用文献数
10 10

A reanalysis dataset is used to establish the relationship between the year-to-year fluctuations in the midwinter storm-track activity over the Far East measured by poleward heat flux associated with subweekly disturbances and the occurrence of the first spring storm with strong southerly winds over Japan (Haru-Ichiban). Our analysis reveals that its early (delayed) occurrence tends to follow the enhanced (suppressed) winter storm-track activity with less (more) apparent minimum in midwinter in the course of the seasonal march. A metric is defined on the basis of the eddy heat flux to measure the reproducibility of the particular seasonal march of the Far East storm-track activity simulated in each of the Coupled Model Intercomparison Project Phase 3 climate models under the present climate. Under a particular global warming scenario, ensemble projection based only on the several models that show the highest reproducibility of the storm-track activity measured with the particular metric indicates that the future enhancement is likely in the midwinter storm-track activity associated with the weakening of the East Asian winter monsoon, implying that Haru-Ichiban is likely to occur earlier in the late 21st century than in the 20th century.
著者
Hiroaki Kawase Munehiko Yamaguchi Yukiko Imada Syugo Hayashi Akihiko Murata Tosiyuki Nakaegawa Takafumi Miyasaka Izuru Takayabu
出版者
Meteorological Society of Japan
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
pp.17A-002, (Released:2020-12-24)

Impacts of historical warming on extremely heavy rainfall induced by Typhoon Hagibis (2019) are investigated using a storyline event attribution approach with the Japan Meteorological Agency Nonhydrostatic Model (JMA-NHM). Control experiments based on JMA mesoscale analysis data well reproduce the typhoon's track, intensity, and heavy precipitation. First, two non-warming experiments are conducted: One excludes both 40-year atmospheric and oceanic temperature trends from 1980 to 2019, and the other excludes the oceanic trend only. A comparison between control and non-warming experiments indicates that historical warming strengthens typhoons and increases the amount of total precipitation by 10.9% over central Japan. The difference between CTL and non-warming experiments without both atmospheric and oceanic temperature trends is larger than that without just the oceanic trend (7.3%). Additional sensitivity experiments without Japan's topography indicate that topography enhances not only total precipitation but also the changes in total precipitation due to historical warming. Through the storyline event attribution approach, it is concluded that historical warming intensifies strength of Typhoon Hagibis (2019) and enhances the extremely heavy precipitation induced by the typhoon.