ASCOS-CCN-ETHZ-01

ASCOS was an interdisciplinary expedition to the central Arctic on the icebreaker Oden from 1 August to 9 September 2008. The expedition focused on processes relating to cloud formation in the summer Arctic and included observations of marine biology and chemistry, atmospheric chemistry, physical oceanography, aerosol chemistry and physics, and meteorology. CCN data of two CCN counters as well as Activation Ratios calculated using total Particle Concentrations from a Condensation Particle Counter. One counter was scanning through five different supersaturations (around 0.1%,0.15%,0.2%,0.4%,0.7%), changing between them in 30 minute intervals. The other counter was constant at one supersaturation, which got changed once (on August 15th) from 0.15% to 0.2%. The values for the corrected supersaturations is given in the Supersaturations.xls file. All the data is in one minute average time, from :00s to :59s, the given time is in the middle of the average (:29s). Each
file consists of four columns: date, number of CCN, activation ratio (number of CCN/total aerosol number from the CPC), flag. The CCN counters as well as the CPC measured in 1s resolution. This data can be provided if necessary.