About Rainfall

Source

The rainfall data displayed by Yakumo Suishin is the “High-Resolution Precipitation Nowcast“ provided by the Japan Meteorological Agency through the Japan Meteorological Business Support Center.

Data Details

The High-Resolution Precipitation Nowcast divides Japan into 250m meshes, providing rainfall intensity and accumulated rainfall values for each.

Update Frequency

Rainfall display on the map is typically updated every 10 minutes.

Rainfall Measurement Method

*) The following text and images are quoted from the Japan Meteorological Agency website.

Weather radar emits radio waves (microwaves) while rotating the antenna to observe rain and snow within a wide range of several hundred kilometers in radius. The distance to the rain or snow is measured from the time it takes for the emitted radio waves to return, and the strength of the rain or snow is observed from the strength of the returned radio waves (radar echo).

Location of Rainfall Measurement Radar

As of 2024, 20 radars are installed throughout Japan.

*) The following image is quoted from the Japan Meteorological Agency website.