Organization and spatiotemporal structure of precipitations induced by the 2016 landfalling Typhoons over northern Japan

Abstract:

In August 2016, four typhoons made landfall over northern Japan and caused widespread damages with heavy rains. This study investigated the organization and spatiotemporal structure of the precipitations brought by these four typhoons. The spatiotemporal structures, in particular, the cell sizes and spell durations of the precipitations are investigated from the hourly precipitations from the Radar Automated Meteorological Data Acquisition System (Radar-AMeDAS) observation. The frequency distributions of precipitation sizes and durations were analyzed by stratifying independent cell sizes and spell durations of precipitations exceeding various precipitation percentile thresholds into different bins. The results indicated that these typhoons brought mostly short-lived, widespread and stronger precipitations with intensity exceeding 55-120 mm/h to the landfall regions. The typhoon induced heavy rains (>20 mm/h) are more frequent and last up to 9 hours although the duration and size of precipitation varied depending on the landfalling region. The supply of atmospheric moisture during all these four typhoons were continuous to form a peak and could possibly bring continuous precipitations up to certain duration. The precipitation amounts over northern Japan are also investigated during the passage of each typhoon through different latitudinal locations. We found that the maximum rainfall occurs over northern Japan when the typhoon location was at 39N.