Wind Profiler Observation on Vertical Structure of a Mei-yu Front Cloud Bands

Abstract

An L-band wind profiler deployed at an industrial park (120.38 E, 22.6 N) close to Kao-Hsiung city in southern Taiwan is utilized to diagnose the vertical structure of Mei-yu frontal precipitating cloud systems observed during 9-11 June 2006. Observational results show several mesoscale convection systems associated with the Mei-yu frontal cloud produced heavy rainfall over Taiwan island. Mei-yu precipitating clouds are classified into three types: convective, mixed convective-stratiform and stratiform based on vertical profile of Signal-to-noise ratio (SNR)/Reflectivity and Doppler velocity during approaching, passing, and leaving stages of the cloud systems. In approaching and pre-passing stages of Mei-yu frontal clouds, a pre-dominant convective precipitation without a significant bright band is observed. In contrast, a pronounced bright band around 4 km was observed during post-passing and leaving stages of the frontal clouds with stratiform precipitation. Doppler velocity profiles show hydrometeors (ice/snow) at 5 km and rain below 4 km for stratiform precipitation. For Mei-yu frontal stratiform precipitation the melting particles accelerations of 3.3 ms À1 km À1 are observed for the bright band region.