A Statistical Study of Wind Gusts in Japan Using Surface Observations

Abstract

In this study, the characteristics of wind gusts in Japan in the period from 2002 to 2017 were examined using surface meteorological data recorded at 151 weather observatories throughout Japan. This study does not focus on particular phenomena, such as tornadoes and downbursts, which cause wind gusts. A wind gust is defined on the basis of the gust factor and the amount of increase and decrease of the 3s mean wind speed from the 10min mean wind speed. A total of 3,531 events were detected as wind gusts. The frequency of wind gusts with more than 25 m s −1 averaged across all observatories is 0.97 per year, which is four or five orders of magnitude higher than the tornado encounter probability in Japan. The frequency of wind gusts in the coastal region is approxi mately three times higher than that in the inland area. Wind gusts occur most frequently in September and least frequently in June. Wind gusts have high activities during daytime, especially in the afternoon. Approximately half of the events are the typhoon-associated wind gusts (WGTYs), which occurred within a radius of 800 km from the typhoon center. Most of the WGTYs occur from August to October. Approximately half of the WGTYs occur in the right-front quadrant of a typhoon with respect to the typhoon motion. The frequency of WGTYs is high in western Japan, whereas the northern and eastern parts of Japan are characterized by a high frequency of wind gusts without a typhoon. In addition, persistent strong winds, which meet the same conditions as wind gusts but without a rapid decrease in the wind speed, were investigated. The frequency of such strong winds is high on the Japan Sea coast, especially in December. The effects of the observational environment on the frequency of wind gusts were also discussed.

Adaptive Wind Gust and Associated Gust-factor Model for the Gust-producing Weather over the Northern South China Sea

“…10a). This finding is consistent with reports from previous studies that the strongest gusts frequently occurred in the northeastern quadrant [48,49] . Note that the smaller number of observations in the SW quadrant partly contributes to its weaker estimated speed since insufficient data representativeness undermines the possibility of capturing extremes.…”

The vortex structure and near‐surface winds of Typhoon Faxai (2019) during landfall. Part I: Observational analysis

“…Using a high‐resolution numerical simulation, Miyamoto et al (2022) showed that the warm sea‐surface temperature extending into the near‐coastal areas and the weak vertical wind shear contributed to Faxai 's compact and axisymmetric inner core structure at landfall. Mashiko (2020) studied the spatiotemporal characteristics of Faxai 's strong winds and gusts during landfall and compared them with strong wind events in the Kanto region during other typhoons that had passed near Tokyo Bay after 1994. He found that only Typhoon Danas (2001) had an axisymmetric inner core structure typical of mature TCs as seen in Faxai (2019).…”