Extended Abstract

Fig. 2. (a) Plan-p osition indicator of the radar reflectivity (dBZ, scale o n right) at 0801 LT 8 August 2009as the p rincipal rai nband designated D3 extended from over the Taiwan Strait to the CMR. (b) Radarreflectivity at 4 km at 0800 LT 8 August indicating individual convective cells along the rainbands (Wanget. al. 2010).4. Contributions due to typhoon location and slow translationYeh and Chang (2009) updated a prev ious cl imatological study of the av eragerainfall amounts when a typhoon existed within various 1° latitude by 1° longitude boxesaround Taiwan. T his new study utilizing the 400 automated surface obs ervation sitesdid not fundamentally change th e distribution in various regi ons of Taiwan. However,this study re-affirms that large rain accu mulations ar e to be expected in the southernCMR region where the disastrous lands lide occurred during Mor akot when the typhoonis near the northern tip of Taiwan. However, these are average rainfall amounts, and donot take into account topographic irregularitie s. Furthermore, the climatological studydoes not take into account the typhoon translation speed (or direction).Kuo et. al. (2010) demonstrated that large variability exists in translation speed oftyphoons near Taiwan. They defined the translation speed of a typhoon crossingTaiwan as the distance between the land fall and departure points divided by thecrossing time. Many of the largest rainfall events associated with tropical cyclones hav eoccurred when this storm translation spee d was small. Indeed, Typhoon Morakot hadone of the slowest translation speeds while it was in the Taiw an Strait and this is clearlyan important factor in the dur ation of the heavy rainfall amounts both in Taiwan and inmainland China region.-62-