- 著者
- Hisaki EITO Masataka MURAKAMI Chiashi MUROI Teruyuki KATO Syugo HAYASHI Hiroshi KUROIWA Masanori YOSHIZAKI
- 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.88, no.4, pp.625-648, 2010 (Released:2010-10-05)
- 参考文献数
- 43
- 被引用文献数
- 15 17
During a cold-air outbreak, a broad cloud band is occasionally observed over the Japan-Sea Polar-Airmass Convergence Zone (JPCZ) that forms over the Sea of Japan from the base of the Korean Peninsula to the Japanese Islands. On 14 January 2001, a broad cloud band associated with the JPCZ (JPCZ cloud band) extended in a southeastward direction from the base of the Korean Peninsula to Wakasa Bay, and it stagnated for half a day. The JPCZ cloud band consisted of two cloud regions: one was a long cloud band extending along its southwestern edge (a developed convective cloud band), and the other was the region consisting of cloud bands normal to a wind direction of winter monsoon (transversal cloud bands). The structure and formation mechanism of the transversal cloud bands were examined on the basis of observations (e.g., satellite images, in situ measurement and cloud-pro.ling radar data from an instrumented aircraft and upper-air soundings from observation vessels) and simulation results of a cloud-resolving model with a horizontal resolution of 1 km.The transversal cloud bands had the following characteristic structures; they extended along a northeast-southwest direction, which was parallel to the direction pointed by the vertical shear vector of horizontal wind in the mixed layer, they mainly consisted of convective clouds, which slanted with height toward the down-shear side, and they widened and deepened toward southwest, as the depth of the mixed layer increased. An examination of simulation results presented that the transversal cloud bands were accompanied by roll circulations. The axes of rolls were oriented nearly parallel to the direction of the vertical shear vector in the mixed layer. An analysis of the eddy kinetic energy budget indicated that the roll circulations derived most of its energy from the mean vertical shear and the buoyancy.
- 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
- 被引用文献数
- 17
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
- Nobuyuki Kayaba Takashi Yamada Syugo Hayashi Kazutoshi Onogi Shinya Kobayashi Koichi Yoshimoto Kenji Kamiguchi Kazuya Yamashita
- 出版者
- (公社)日本気象学会
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.12, pp.1-5, 2016 (Released:2016-01-20)
- 参考文献数
- 8
- 被引用文献数
- 28
The Japan Meteorological Agency (JMA) completed its second global atmospheric reanalysis, the Japanese 55-year Reanalysis (JRA-55). However, the horizontal spatial resolution of JRA-55, TL319 (about 55 km), is insufficient for representing the hilly topography of the Japanese islands. Therefore, to reproduce extreme events caused by the hilly topography and their long-term climatological change in Japan, JMA has conducted a dynamical regional downscaling, called DSJRA-55, based on JMA's operational mesoscale model, which has a horizontal resolution of 5 km. DSJRA-55 receives its initial field and boundary conditions from the JRA-55 reanalysis. DSJRA-55 is historically the first products in the world that covers very long term for 55 years with very high resolution in 5 km. Furthermore, DSJRA-55 does not perform data assimilation; instead, initial field and boundary conditions are given at frequent intervals to the downscaled model and short-range forecasts are performed. Then, successive forecasts are connected continuously to create the DSJRA-55 product. In early evaluation results, DSJRA-55 was able to reproduce observed temperature and precipitation during 1958-2012. Although it showed a systematic temperature bias in some regions and seasons and it underestimated the frequencies of heavy-rain days and heavy-rain hours, DSJRA-55 reproduced the overall distribution of orographic precipitation well. DSJRA-55 is therefore expected to be useful for analyzing past extreme events and for statistical studies of long-term climate.
- 著者
- Masuo NAKANO Teruyuki KATO Syugo HAYASHI Sachie KANADA Yoshinori YAMADA Kazuo KURIHARA
- 出版者
- (公社)日本気象学会
- 雑誌
- 気象集誌. 第2輯 (ISSN:00261165)
- 巻号頁・発行日
- vol.90A, pp.339-350, 2012 (Released:2012-06-07)
- 参考文献数
- 32
- 被引用文献数
- 14 34
A 5-km-mesh nonhydrostatic cloud-system-resolving regional climate model (NHM-5km) has been developed at the Meteorological Research Institute (MRI) of the Japan Meteorological Agency (JMA) by improving upon the JMA operational mesoscale model (MSM). Three major changes have been made to MSM: the Kain-Frisch convective parameterization scheme has been improved to reduce the incidence of false predictions of rainfall areas along coastlines during the warm season, a spectral nudging method has been introduced to avoid phase-gap between the inner model (NHM-5km) and the outer model, and a Simple Biosphere model has been applied for sophisticated representation of land surface processes. This article presents details of the first two of these modifications.A present-day climate simulation is performed using NHM-5km by nesting within the results of a 20-kmmesh atmospheric global climate model (MRI-AGCM3.2S). Taylor’s skill score is used to compare the performances of NHM-5km and MRI-AGCM3.2S in terms of reproducing the spatial pattern of precipitation-based extreme indices over the Japanese Islands. The comparison shows that NHM-5km yields a significant improvement in reproducing the present-day climatology (e.g., the maximum number of consecutive dry days and the simple daily precipitation intensity index), suggesting that NHM-5km is a reliable tool for accurately predicting future changes in extreme weather at a fine spatial resolution.
- 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)
- 被引用文献数
- 17
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
- Kyosuke Ishii Syugo Hayashi Fumiaki Fujibe
- 出版者
- 日本大気電気学会
- 雑誌
- Journal of Atmospheric Electricity (ISSN:09192050)
- 巻号頁・発行日
- vol.34, no.2, pp.79-86, 2014 (Released:2014-08-28)
- 参考文献数
- 24
- 被引用文献数
- 2 20
The temporal and spatial distributions of cloud-to-ground (CG) lightning in and around Japan were examined for a seven-year period (2002?2008) by using lightning location data from the Lightning Detection Network System operated by the Japan Meteorological Agency. The frequency of CG flashes was found to be high over land area in summer. During winter, many CG flashes were located along the coast of the Sea of Japan of central Honshu (Hokuriku area) and off the coast of the Pacific side (Kanto-Tokai area). A detailed analysis of the Hokuriku and Kanto-Tokai areas revealed diurnal variations characterized by a peak in the afternoon for inland areas, and a peak in early morning for coastal and offshore areas of the Hokuriku area in summer. For winter, the diurnal variation of CG flash density is indistinct in the Hokuriku region, where CG flashes are strongly concentrated within 20 km from the coastline, whereas it has a maximum in the early morning off the coast of the Kanto-Tokai area.