Cloud Condensation Nuclei concentration (CCN) monthly medians measured at Kennaook Cape Grim 1981 to 2002 using the static thermal diffusion chamber

This data set is the record of monthly median number concentration for cloud condensation nuclei active at 1.2%, 0.96%, 0.71%, 0.47% and 0.23% measured at the Kennaook Cape Grim Baseline Air Pollution Monitoring Station (KCGBAPS) between 1981 and 2002. The KCGBAPS is located on the northwest tip of Tasmania (40.6833° S, 144.6833° E). Commencing operations in 1976, and in its current facilities since 1981, the Baseline Air Pollution Station at Kennaook Cape Grim is Australia’s contribution to international efforts for monitoring the global background atmosphere for trends due to human activities and natural variability. The data published here are the monthly medians under baseline conditions (i.e. when wind direction measured at 10 m was in the 190°to 280° ‘baseline’ sector. Daily mean spectra were calculated from a minimum of three daily spectra, and the monthly medians are determined from the daily means calculated from manual measurements. The number of baseline spectra included in each monthly medium are also published with the data set. For some months the number of baseline spectra is small; a factor that should be taken into account when using these data. Usually the cause for few spectra is a combination of the manual operation of the CCN counter and a low baseline frequency. In cases where no baseline spectra were recorded in a month the NAN are included in the data set. Subsets of these data have been described in Ayers and Gras (1991), Ayers et al. (1997), Boers et al., (1994), Gras (1990), Gras (1995) and Gras and Keywood (2017). See KCGBAPS_CCN_Static_Thermal_Diffusion_Chamber_1981_2002_README.pdf for references