关键词: Doppler雷达, 风场反演, 暴雨, 中尺度系统

Abstract: The single-Doppler radar wind retrieval method is useful to enhance the applications of the Doppler radar in the observing and forecasting of mesoscale weather system. This paper shows that the VAD and VAP methods can be derived from the same relationship based on the azimuthal uniform wind assumption. By using this assumption, an IVAP (Integrating VAP) method is developed, which can overcome the sensitivity of VAP method to the short wave and too smooth property of VAD method in Doppler velocity. By using the IVAP technique, the wind fields associated with a heavy rainfall case in Shanghai (Aug. 5^th, 2001) are retrieved using a Doppler radar located at the Hongqiao Airport. Retrieved winds using azimuthal sector length of 9°,18°,45°, and 90° indicate that using shorter sector length can exhibit the cyclonic stream and mesoscale convergence line related to the heavy rainfall. The quality of the retrieved winds is validated by using surface observations and wind-profiler data. Comparison of the radar retrieved winds with surface observed winds indicates that retrieved winds have good correlation with surface observations. The larger the sector length the higher is the correlation coefficient. Twenty wind-profiler data at the same height and time also have good correlation with Doppler radar retrieved winds. The square mean errors ofu or v are about 2m·s^-1. All of the results indicate that the IVAP method is more objective to be used in applications of Doppler radar.

Key words: Doppler radar, wind retrieval, storm, meso-scale system