- 著者
- Ken Usui Toshiki Iwasaki Takeshi Yamazaki Junshi Ito
- 出版者
- 公益社団法人 日本気象学会
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.18, pp.140-146, 2022 (Released:2022-07-06)
- 参考文献数
- 15
We conducted numerical simulations on a case of local “Karakkaze” wind on 23 March 2009. On this day, an aircraft crashed on landing at Narita Airport in the eastern Kanto Plain in Japan in the early morning when surface winds were significantly strengthened. Numerical simulations were used to elucidate the characteristics and mechanism of the strong wind over the Kanto Plain. This strong wind was identified as the Karakkaze wind, which occurs in the lee of the convex mountain range northwest of the Kanto Plain. The vertical shear associated with the Karakkaze wind could cause strong turbulence near the surface. The results of a sensitivity experiment suggest that the presence of the mountain convexity is essential for the development of the Karakkaze wind. Backward trajectory analyses reveal the area where the Karakkaze wind originated upstream of the mountain range. The horizontal wind speed in this area is even weaker than in the northern area. However, unlike in the northern area, the air with large momentum descends from altitudes much higher than the height of the dividing streamline owing to the mountain convexity, thereby driving strong surface winds in the leeward area.
- 著者
- Ken Usui Toshiki Iwasaki Takeshi Yamazaki Junshi Ito
- 出版者
- 公益社団法人 日本気象学会
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2022-023, (Released:2022-06-02)
We conducted numerical simulations on a case of local “Karakkaze” wind on 23 March 2009. On this day, an aircraft crashed on landing at Narita Airport in the eastern Kanto Plain in Japan in the early morning when surface winds were significantly strengthened. Numerical simulations were used to elucidate the characteristics and mechanism of the strong wind over the Kanto Plain. This strong wind was identified as the Karakkaze wind, which occurs in the lee of the convex mountain range northwest of the Kanto Plain. The vertical shear associated with the Karakkaze wind could cause strong turbulence near the surface. The results of a sensitivity experiment suggest that the presence of the mountain convexity is essential for the development of the Karakkaze wind. Backward trajectory analyses reveal the area where the Karakkaze wind originated upstream of the mountain range. The horizontal wind speed in this area is even weaker than in the northern area. However, unlike in the northern area, the air with large momentum descends from altitudes much higher than the height of the dividing streamline owing to the mountain convexity, thereby driving strong surface winds in the leeward area.
- 著者
- Shiori Sugimoto Rui Ito Koji Dairaku Hiroaki Kawase Hidetaka Sasaki Shingo Watanabe Yasuko Okada Sho Kawazoe Takeshi Yamazaki Takahiro Sasai
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.14, pp.46-51, 2018 (Released:2018-04-01)
- 参考文献数
- 32
- 被引用文献数
- 7
To evaluate the influence of spatial resolution in numerical simulations on the duration of consecutive dry days (CDDs) and near-surface temperature over the central mountains in Japan, a regional climate model was used to conduct two experiments with horizontal resolutions of 5 and 20 km. Compared with observations, the spatial and temporal features of the CDDs were simulated well in the 5 km experiment, whereas in the 20 km simulation they were overestimated over the mountains and underestimated in the surrounding regions. The accuracy in the simulated CDDs affected the near-surface temperature in the model. In years with a difference of more than five days in the CDDs between the 5 and 20 km experiments, near-surface temperatures over the mountains were 0.2-0.3 K lower in the 5 km simulation compared with the 20 km simulation. This was due to the lower number of CDDs in 5 km simulation causing active cloud convection and reduced net radiation at the ground, resulting from a large decrease in the solar radiation at the ground. In addition, a land surface wetness controls a spatial heterogeneity of temperature difference between two experiments.