Cloud Condensation Nuclei (CCN) Counter data

This dataset contains cumulative data-concentrations per cm3 with critical supersaturations (Sc) less than the supersaturation (S) value at the top of the column. Concentrations are normalized to sea level pressure. There are up to three files per flight. The file labeled both (e.g., JY12both.txt) is the best—it is a limited data set for time periods when both DRI CCN spectrometers were sampling ambient and were in agreement with each other over at least an overlapping supersaturation range, sometimes nearly the entire S range from 0.02% to 1% S, or at least at some S value. The other two files are during periods when only one instrument sampled ambient aerosol. The new instrument (e.g., JY12new.txt) is more valid for higher S (>~ 0.1%) whereas the old instrument is more valid for S <~ 0.1%. NOTE: The old spectrometer on the first 3 and last 3 flights has been updated. All concentrations were multiplied by 0.71 for only the old spectrometer for these 6 flights to correct an error in the original files. For 5 of these 6 there is only data from the old spectrometer. July 6 is the only one of these with data from both instruments. All flights have been carefully checked by the data source and the other 7 flights did not need this correction.