| Field observation experiment of the relationship between cloud condensation nuclei (CCN) number and the physical and chemical properties of the atmospheric aerosol conducted at Bright Summit Peak of Mt. Huang, Anhui Province from June 30 to July 28,2014. The aerosol number-size distribution, cloud condensation nuclei (CCN) concentration, hygroscopic growth factors, chemical composition were collected with wide-range particle spectrometer (WPS), CCN counter (CCNc), Hygroscopic Tandem Differential Mobility Analyzer (HTDMA), Anderson cascade impactor, respectively. This work discussed the variation of CCN number, fitted CCN activation spectrum. According to Kohler theory, the CCN concentrations were calculated from the hygroscopic growth factors and chemical composition with the aerosol number-size distribution. And we discussed the influence of the variation of number-size distribution, mixed mode and chemical composition on CCN number.The results show that the CCN concentration varied with aerosol number concentration consistently, the CCN concentration were 419±414 cm-3,806±720cm-3,1292±905cm-3, 1380±873 cm-3, and 1506±867 cm-3 at supersaturation levels of 0.1%,0.2%,0.5%,0.7%, and 1%, respectively. The equation Nccn=CSk and Nccn=N0(1-exp(-BSk)) were fitted CCN spectrum, and the latter is well fitted to the average CCN spectrum over the observation period while both of them reflected average status. The CCN concentrations were calculated from the hygroscopic growth factors and the aerosol number-size distribution. The calculated CCN concentrations and measured CCN concentrations show close correlation and high accuracy. The difference between internal and external mixed mode, pure inorganic salt and enjoying 40% WSOC is very small. An analysis of the variation of particle number-size distribution, hygroscopic growth factors, and chemical composition indicates that the change in particle number-size distribution is the main factor affecting the CCN concentrations. |
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