Observations of temperature profiles by 443 MHz wind profiling radar using a radio acoustic sounding system in Okinawa

The present study is devoted to developing a radio acoustic sounding system (RASS) for the 443 MHz wind profiling radar (443 MHz WPR) installed at the Ogimi Wind Profiler Facility of the National Institute of Information and Communications Technology (NICT) in Okinawa, Japan.We used four fixed horns attached to the sides of the 443 MHz WPR antenna. Additional 15 portable horn speakers were also installed to transmit acoustic waves at frequencies of 900–1050 Hz, which is suitable for the 443 MHz WPR with RASS (443 MHz WPR/RASS) observation.We also developed the software to switch active speakers adaptively by considering the real-time raytracing results of acoustic wavefronts. In the software, four fixed speakers are always activated and several portable speakers are selectively used in order to efficiently obtain strong RASS echoes.Aiming at unmanned operation of the 443 MHz WPR/RASS, a remote control and monitoring system for 443 MHz WPR/RASS observation and a data processing system to derive virtual temperature profiles were developed.Virtual temperature profiles obtained using the 443 MHz WPR/RASS were evaluated by comparison with the data from radiosondes launched from the radar site in 2006.

Research Highlights
► A radio acoustic sounding system for the 443 MHz wind profiler was developed.
► Software to switch active speakers adaptively was newly developed.
► Remote control and monitoring system for RASS observation were developed.
► Temperature profiles were evaluated by comparison with the data from radiosondes.