| Summary: | 碩士 === 國立中央大學 === 大氣物理研究所 === 98 === The purpose of this study is to characterize the cloud condensation nuclei (CCN) measured at Lulin Atmospheric Background Station (LABS, 23.47° N, 120.87° E, 2862 m MSL), Mt. Bamboo (25.11° N, 121.31° E, 1103 m MSL), and Fugueijiao (25.15°N, 121.33° E, 229 m MSL) using a DMT (Droplet Measurement Technologies) continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter. The study conducted the observations at three sites. First of all, the measurements of CCN were performed at LABS from October 30 to November 1, 2008 and during December 9-12, 2008. As a result, an obvious diurnal variation of CCN concentrations was observed, which was influenced by valley breeze in the daytime at LABS. Second, the measurements of CCN were performed at Mt. Bamboo during February 14-19, 2009. It showed that the air mass from different sources can affect the concentration and particle size of cloud droplets which are formed by CCN. Meanwhile, CCN concentrations apparently decreased during the cloud event. The last CCN observation was conducted at Fugueijiao during March 26-31, 2009. Consequently, it shows that there is an obviously scavenging effect on CCN particles when precipitation occurred. Furthermore, according to the expression NCCN = CS k, the CCN spectra can be described. The fitted spectral parameters C (about 100) and k (about 0.70) for LABS case can be classified to be continental type. However, the CCN spectra of Mt. Bamboo and Fugueijiao were shown to be maritime origin. The parameters C (about 1000) and k (about 0.40) for both cases were similar.
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