The "precipitation nowcast method" is known as a method for predicting precipitation distribution.This tracks the movement of the precipitation pattern captured by the weather radar, and predicts it assuming that it will continue to move in the future.The advantage of this method is that the amount of calculation is much smaller than that of simulation, but the disadvantages are that the prediction accuracy drops rapidly and that the vertical movement of raindrops is not taken into consideration in order to track the precipitation pattern on the plane. is.

　The state-of-the-art "Phased Array Weather Radar" (installed at Osaka University) can scan raindrops up to 30 km away at a high frequency of every 60 seconds without any gaps.In order to utilize the big data of this radar in the precipitation forecast, the international joint research group has developed a "3D precipitation nowcast method" that captures the three-dimensional movement of the observed raindrops and predicts them under the assumption that they will continue to move in the future. ..In addition, we built a system that executes forecasts in real time, and started the world's first real-time demonstration of precipitation forecasts up to 30 minutes after a 10-second update.This precipitation forecast will be published by RIKEN on the Internet as much as possible with the permission of the Japan Meteorological Agency.

　In 2016, we developed a "guerrilla rainstorm" prediction method that utilizes the supercomputer "K computer" and phased array weather radar, and succeeded in predicting high-definition guerrilla rainstorms up to 30 minutes later, although not in real time. ..Together with this short-time forecasting method, it is expected that ultra-high-speed and ultra-high-definition weather forecasts that have never been imagined will be possible in the future.