[AAS11-P20] Characteristics of Cloud Condensation Nuclei over the Urban Areas Measured at Tokyo Skytree
Keywords:cloud condensation nuclei number concentration, condensation nuclei number concentration, effective radius, fog droplet number concentrations
Measurements were carried out at TST (35.71°N, 139.81°E, 458m,a.g.l), from 3 to 30 June 2016. In this study, aerosol number size distribution, condensation nuclei (CN) number concentrations (NCN), CCN number concentrations (NCCN) with four supersaturations (SS%) were measured. Fog droplet size distributions and fog droplet number concentrations (NFog) were also measured. Using these data, we obtained the hygroscopic parameter (κ) and the effective radius (Reff) of fog droplets.The results obtained at TST were compared with observation data of the summit of Mt. Fuji where similar observations were made.
The average value of NCCN at TST was larger than that of the summit of Mt. Fuji.. The average value of κ at TST was smaller than that of the summit of Mt. Fuji . The CCN properties of aerosols did not vary significantly with air mass origins. As a result of the CCN characteristics of the period covered with clouds without drizzle, there was no positive correlation between the NFog and NCCN. Also, there was no negative correlation between Reff and NCCN like the microphysical relationship known as the Twomey effect. This is considered to be due to the small variation of NCCN at TST. The relationship between Reff and NCCN under SS0.12% could be regarded as part of the negative correlation between Reff and NCCN obtained at the summit of Mt. Fuji .
 IPCC 2013, http://ipcc.ch/
 Watanabe A. (2015), Tokyo University of Science Master's thesis
 Towmey, S. (1959), Geofis .Pura Appl., 43, 243-249