Tuesday, 12 August 2003: 11:29 AM
Temporal and Spatial Variations of Precipitation of Landfalling Typhoons in the Taiwan Area
This study examines the temporal and spatial variations of precipitation structure of landfalling typhoons by using reflectivity data observed by the Doppler radars in Taiwan. Five typhoons landed Taiwan during the period of 1996-2001 with different tracks and intensity were analyzed. The grid-averaged reflectivity data in four quadrants divided in terms of the direction of movement were used to show the evolution of the eyewall, the rainbands in the annular area outside the eyewall, and areas extended to 300 km from the center of the storm. More than 60 hours radar data with time interval of 6 or 8 minutes were analyzed in this study. The contraction of the eye, the concentric eyewall evolution, the outward and/or inward propagating spiral rainbands, and the organized convective precipitation areas related to the Taiwan topography were identified in this study. The asymmetric characteristic of the precipitation structure of typhoons was documented and the effect of vertical wind shear and the topography of Taiwan on the nature of these precipitation features were also described.