Characteristics of CCN concentration and their effect on microphysical properties of clouds over the neighborhood of the East China Sea

(1)利用我们过去飞机观测的气溶胶大小、数量和相对湿度数据以及地面观测的气溶胶成分数据，研究了大陆性污染气团对东海气溶胶光学特性的影响。研究指出，来自中国、韩国和日本的空气污染物有时会对东海的大气造成强烈污染。(2)通过对以往飞机观测资料的详细分析，研究了云中新的云凝结核（CCN）的形成过程。新的云凝结核是由SO_2转化为SO_4 ~（2-）粒子形成的。(3)2005年10月16日至2006年1月30日，在奄美大岛北方观测了云凝结核（CCN）浓度的时间变化，以及气溶胶颗粒、黑碳和SO_2、NOx和O_3气体浓度的时间变化。这些风玫瑰图表明，在中国、韩国和日本的风向下，随着气溶胶粒子、黑碳或SO_2气体和NOx浓度的增加，CCN浓度急剧增加。这些结果表明，来自中国、韩国和日本的大气污染物对东海大气造成了显著的污染，并显著增加了东海的CCN浓度。(4)通过对比云凝结核（CCN）浓度和SO_4^2-浓度，分析了CCN对低云微物理特性的影响化学天气预报系统获得的云滴光学有效半径分布以及卫星MODIS数据估计的云滴光学有效半径和多云天空光学厚度结果强烈表明，高CCN浓度会降低云滴光学有效半径，增加多云天空光学厚度东海。

(1) Effects of continentally polluted air mass on aerosol optical properties over the East China Sea were studied by using data of aerosol size and number and RH observed by our past aircraft observation and aerosol composition observed on ground observation. The study pointed out that air pollutants originated from China, Korea and Japan sometimes strongly pollute the atmosphere over the East China Sea.(2) Formation process of new cloud condensation nuclei (CCN) in clouds was examined by analyzing our past aircraft observation data in detail. It was strongly suggested that new CCN are formed by sulfate (SO_4^2-) particles transformed from sulfur dioxide (SO_2) in clouds.(3) The time variation of CCN concentration in addition to aerosol particles, black carbon and gases of SO_2, NOx and O_3 concentrations was observed at the northern end of Amami-Oshima Island from 16 October 2005 through 30 January 2006. These wind rose figures showed that CCN concentration drastically increases with increasing aerosol particles, black carbon or gases of SO_2, and NOx concentrations under the wind directions from China, Korea and Japan, These results strongly suggest that air pollutants originated from China, Korea and Japan remarkably pollute the atmosphere over the East China Sea and significantly increase CCN concentration over the East China Sea.(4) The effect of CCN on microphysical properties of lower clouds was analyzed by comparing CCN concentration with SO_4^2- distribution obtained by Chemical weather FORecasting System and optical effective radius of cloud droplets and optical thickness of cloudy sky estimated by satellite MODIS data The results strongly suggested that high CCN concentration decrease optical effective radius of cloud droplets and increase optical thickness of cloudy sky over the East China Sea.