The Meteorological Agency will use a global positioning system to analyze water vapor content and improve its accuracy in predicting torrential rain, officials said.
GPS is used to observe seismic changes via radio waves sent from satellites to antennas on the ground, but large amounts of water vapor can slow the arrival of radio waves, causing errors in observation.
The agency has developed a method of using that delay to estimate the amount of water vapor in a certain area so they can predict the arrival of heavy rain more accurately. The new method will be put into effect next March, they said.
Simulations of previous flood disasters conducted with the new GPS technology have shown that the heavy rains that left houses submerged in the city of Shizuoka on June 30, 2004, could have been predicted one to five hours in advance.
The deaths of five people in Kobe who were swept away by a swollen river last July 28 also could have been prevented.