Rapid 3D Scanning High Resolution X-Band Phased Array Weather Radar

Urban areas in Japan suffer from more and more severe weather disasters such as heavy rain fall or tornadoes recently. Particularly around Tokyo in summer season, rapidly developing cumulonimbi produce heavy rain; occasionally causing floods.

To observe the developing stage of cumulonimbi for analyzing and predicting severe weather, weather radars are expected to operate for volume scan of whole three-dimensional space with high spatial resolution and short observation cycle. With conventional weather radars equipped with parabolic antennas, however, it takes five to ten minutes to finish volume scan of limited elevation angles.

Japan Radio Co., Ltd. independently developed a prototype of single polarization x-band phased array weather radar. By adopting digital beamforming technique for simultaneously forming multipule receiving beams, it takes only 30 seconds to finish volume scan of the cylindrical space with a radius of 80 km and height of 15 km. And more, this radar outputs radar parameter such as reflectivity with high spatial resolution of 50 m.

We installed this radar in the summer of 2015 in Chiba city about 45 km east away from Central Tokyo and started experimental operation. With this radar, we have succeeded in observing some severe storm cases. One of the severe storm cases was hail at March 28, 2016. Our radar succeeded in detecting the temporal change of echoes above Shinjuku which rapidly became stronger and fell down in just few minutes.

For more effective use of our observation data, we are considering providing our data to investigators on mechanism of severe weather or researchers of disaster prevention systems.