THE JAPAN NEWS


 

A project team including the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the Meteorological Research Institute (MRI) and other institutions has succeeded in developing the basic technology to predict the coming of disastrous torrential rain in specific areas at least half a day before its occurrence at 50 to 70 percent probability.

JAMSTEC is a state-run research and development agency based in Yokosuka, Kanagawa Prefecture, and MRI is a function of the Japan Meteorological Agency located in Tsukuba, Ibaraki Prefecture. The two institutions and others have been working to develop technologies which would help reduce human casualties from torrential rain.

The new technology will utilize the “K” supercomputer in Kobe for calculations.

The project team aims to put a forecast system into actual use to enable residents to evacuate more quickly by the 2020s. Predicting torrential rain is one of the key government projects involving the use of supercomputers in applied technological development. The volume of weather-related data has been increasing remarkably in recent years, making it necessary to better utilize collected data. The advancement of supercomputers and calculation methods are the key to achieving that goal.

The project team developed a method to calculate the probability of torrential rain based on repeated calculations of massive data, each time slightly changing the preconditions. They then verified their method using the K supercomputer to conduct calculations based on accumulated data from torrential rains in the past.

The project team used data from torrential rain that hit the Kanto and Tohoku regions in September 2015. The team calculated weather data collected on the day and from the previous day, as well as the massive data collected by Himawari-8, a geostationary meteorological satellite which has been operating since July 2015.

A result of the calculations was a prediction of areas where the amount of rainfall had a 70 percent probability of exceeding 100 millimeters during a 24-hour period. These areas were found to roughly overlap with areas in Tochigi Prefecture and other places where rainfall actually had exceeded 100 millimeters.

The supercomputer currently used by the meteorological agency has a calculation speed that is one-12th that of the K computer and therefore has lower processing capabilities.