Gust prediction by a high density ground surface observation network (POTEKA)

Abstract

POTEKA (POint TEnki KAnsoku in Japanese) compact weather stations can observe seven meteorological variables, including temperature and pressure. In Gunma and Saitama prefectures, Japan, about 150 POTEKAs have been installed to create a high density ground surface observation network which has a resolution of approximately 2 km. This observation network has observed multiple downburst and damaging wind events, and has revealed the characteristics of downbursts, such as changes in the meteorological variables and phenomena proceeding these events (Iwashita et al. 2019). By analyzing the downburst event on Jun 15, 2015, which was the most damaging event observed by the network, we have succeeded in developing a downburst gust prediction system that utilizes the high density ground surface observation data. The high density ground surface observation network can be used to predict the occurrence of a downburst event several minutes in advance using temperature and pressure data. The cumulonimbus forward velocity can be calculated from the distance and time between the locations of temperature drops. Areas with a high probability of gust occurrence can be estimated based on the magnitude of the temperature drop. Thus, it may be possible to predict the occurrence times and locations of downburst gust events by utilizing high-resolution observations of the temperature and pressure.