Status of sodar observation in Japan

Long-term sodar observations were carried out by a monostatic system provided with a paraboloidal dish of 16 m diameter. The general characteristics of the lower troposphere were determined, showing that there are diurnal and seasonal variations of wavy layers and thermal plume activities at a height range 200-1000 m. The visualized temperature structure obtained by sodar observation revealed that small-scale ordered motions play an important part in the clear troposphere. Echo intensity corresponded to the structure constant, squared C(T), which was found to gradually decrease with height. The characteristic feature of the maritime planetary boundary layer observed at Miyakojima Island was that thermal plume type sodar echoes appeared in nighttime during the period of GARP AMTEX 1975. A truck-mounted sodar is developed for Doppler wind measurements. Future plans include radiometeorological applications of sodar.