The web‐based accumulated rainfall amount monitoring system by X‐band MP radar

Abstract

AbstractFlood damage due to heavy rain is quite severe in Japan during the annual typhoon season, which causes death and serious destruction every year. Moreover, serious damage (flood damage and landslide disaster, etc.) by localised torrential rains and local heavy rains has increased in Japan in recent years. The Ministry of Land, Infrastructure, Transport and Tourism of Japan started the operation of an X‐band Multi‐Parameter (MP) radar system in February 2012, at 23 observation stations in Japan. Rainfall observations by the X‐band MP radar system are more detailed than by the past C‐band radar. However, now, applications of X‐band MP radar data are mostly only for displaying 1‐min rainfall images. The Japan Meteorological Agency is providing a standard of the rain situation (strength of rain), which shows hazard levels of the rainfall amount in 1 h. Those hazard levels of the accumulated rainfall amount are quite important to estimate disaster events. Thus, in the present study, an accumulated rainfall amount monitoring system is developed. The accumulated rainfall amount can be clearly shown on a PC monitor or a mobile terminal monitor. It takes up to 5 min to show the results on the web site after having observed rainfall in 1 h. It was shown that this is an effective system for local governments, etc. to monitor rainfall amount information, and to give flood warnings and evacuation orders to residents in the vicinity.