Since March 2012, multi-year ground-based observation of atmospheric aerosol particles has been carried out in Tsukuba, Japan to characterize the aerosol particle number concentrations (NCs), air mass origin relevance, and specifically, their cloud condensation nuclei (CCN) and ice nucleating particle (INP) characteristics. The CCN NCs at any water supersaturation (SS) exhibit strong seasonality, being higher in winter and lower in summer; this pattern is similar in the polluted urban environment in East Asia and contrary to that in the Pacific coastal region. The hygroscopicity (κ) is generally high in early autumn and low in early summer, likely due to the seasonal difference of synoptic-scale systems. In contrast, the INP NCs and ice nucleation active surface site density (n_s) at defined temperature (−15 to −35°C) and SS (0%-5%) lack clear seasonal influence. The average INP NCs and n_s in this study were comparable at warmer temperatures and approximately one order of magnitude lower at colder temperatures, compared with those in other urban locations under limited dust impact. Moreover, the n_s values were one to four orders of magnitude lower and exhibited weaker temperature dependence than previous parameterizations on mineral dust particles.

自2012年3月以来，在日本筑波市对大气气溶胶颗粒进行了多年地面观测，以表征气溶胶颗粒浓度（NCs），空气质量成因的相关性，尤其是其云凝结核（CCN）和冰核颗粒（INP）的特性。在任何水过饱和度（SS）下，CCN NCs都表现出强烈的季节性，冬季较高，夏季较低。这种模式在东亚受污染的城市环境中是相似的，与太平洋沿海地区相反。吸湿性（κ）通常在秋季初高而夏季初低，这可能是由于天气尺度系统的季节差异所致。相反，INP NCs和冰核活性表面位点密度（n _s）在规定温度（−15至-35°C）和SS（0％-5％）下缺乏明显的季节性影响。与其他尘土影响有限的城市地区相比，本研究中的平均INP NCs和n _s在较高温度下可比，而在较低温度下约低一个数量级。此外，与先前对矿物粉尘颗粒的参数化相比，n _s值低1-4个数量级，并且表现出较弱的温度依赖性。