COHERENT DOPPLER LIDAR OBSERVATION OF THE LOCAL EASTERLY WIND 'KIYOKAWA-DASHI' IN JAPAN

摘要

The Kiyokawa-dashi is a local strong easterly wind that occurs in the atmospheric boundary layer over the Shonai Plain of the northern Honshu in Japan. Although the mechanics of occurrence of the Kiyokawa-dashi has been investigated, an established explanation of the mechanism of occurrence has not been made due to the insufficient meteorological and spatial information. A 2 μm eye-safe airborne coherent Doppler lidar has been developed at the National Institute of Information and Communications Technology (NICT). The coherent Doppler lidar is a powerful and useful system for studies in the wind field. The experimental ground-based observations were carried out to observe the Kiyokawa-dashi on July 18, and August 7 and 8, 2003. Vertical wind profiles of the Kiyokawa-dashi were obtained by the coherent Doppler lidar with the velocity-azimuth display technique with a height resolution of 90 m for every 5 minutes. The coherent Doppler lidar captured in detail the temporal variations of wind velocity, wind direction, vertical wind velocity and the critical height (horizontal wind velocity = 0 m/sec).