| dc.description.abstract | This Study used 2009 SoWMEX (Southwest Monsoon Experiment) data, form June 3 to June 14,to investigate precipitating physical property. There are five Joss-Waldvogel disdrometers located at NCU, Hsiayun, Douliu, Chiayi, Alishan to observe DSD characteristics in 2009 Mei-yu season.
Joss-Waldvogel disdrometer always underestimate small raindrop In heavy rain events. This study used Dead Time Correction to revise all observation data when rainfall rate over 20mm/hr to improve this underestimation problem.
The DSD analysis result shows no matter how rainfall rate is, Alishan has more small raindrops than other stations. However, Hsiayun usually observed less small raindrop than others when rainfall rate greater than 5mm/hr. Douliu and Chiayi have less small raindrop concentration when rainfall rate less then 5mm/hr. These results show that there is no geographic DSD different in northern and southern Taiwan, but each station has its own DSD properties.
Comparison studies on the slope parameter(Λ) and shape parameter(μ) show that five station’s Λ are almost the same, but Alishan’s majority μ is smaller than others, Hsiayun’s is opposite. Compared with the D_m-N_w relation deduced by Bringi et al. (2003), there are similar DSD results in stratiform rain at all stations, while the DSD in convective rain are located at the region between maritime and continental-like cluster, NCU and Alishan more close to maritime-like cluster.
Finally, this study used the same reflectivity to compared the different microphysical parameters between five stations. The counterpart reflectivity of rainfall rate to separate stratiform and convective precipitation type reflectivity is 37.5dBZ. The distribution of Λ and μ at all stations almost have same tendency, but only Hsiayun is different when reflectivity is large. In the same reflectivity, Alishan station has smaller D_m than others.
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