山西云凝结核时空分布特征观测

选取2011年1~12月山西太原云凝结核(CCN)观测数据,对CCN的季节、月、日变化特征进行了分析,并与国内外同类研究进行了对比.结果发现,冬季CCN数浓度最高,春秋季次之,夏季CCN数浓度最低.CCN数浓度的最高值出现在1月,最低值出现在6月.夏季较多的降水天气对CCN的湿清除作用明显,冬季供暖期间(11~12月及1~3月),CCN数浓度明显增大.CCN数浓度日变化一般呈现两个峰值,分别出现在07:00~11:00和17:00~20:00.利用公式N=CSk拟合了不同季节地面CCN核谱,得到春夏秋冬四季对应的拟合参数C值分别为10983、2454、7614、16421,k值均小于1,为典型的大陆型核谱.通过2013年夏季在山西中部地区开展的CCN飞机观测,研究了CCN数浓度的垂直廓线.CCN数浓度在近地面最大,随高度逐渐降低.在0.3%和0.4%过饱和度下,2000m以下CCN数浓度平均量级均为103cm-3, 3000m以上CCN数浓度平均量级降低至102cm-3.

Observational study of the spatial-temporal distribution of cloud condensation nuclei in Shanxi Province,China

Observational data of Cloud Condensation Nuclei (CCN) from January to December 2011 was used to analyze the CCN spatial-temporal distribution properties including the seasonal, monthly and daily distribution in Shanxi Province, and the results were compared with the similar researches in other places of China and abroad. The CCN number concentration (NCCN) showed obvious seasonal variation, the average value of NCCN was highest in Winter and lowest in Summer. The maximum NCCN occurred in January and the lowest value occurred in June. More precipitation days in summertime had strong wet scavenging effect on NCCN. NCCN significantly increased during the local winter heating period. A bimodal pattern was presented in the NCCN diurnal variation. Two peaks appeared at 07:00-11:00 am and 17:00-20:00 pm, respectively. The fitted CCN spectra of four seasons were obtained by using the expression N=CSk. The fitted parameters C were 10983, 2454, 7614 and 16421 for Spring, Summer, Autumn and Winter, and all the values of k were less than 1, which showed the typical continental nuclei spectrum characteristics. The NCCN vertical profiles were acquired based on the airborne measurements of CCN in summertime of Shanxi, 2013. The largest NCCN appeared close to the ground surface, and the NCCN decreased with height. The average magnitude of NCCN was 103cm-3below 2000m height and 102cm-3 above 3000m height.