Data Set Title - ESCAPE CCN measurements Data Set Author(s) - Lead and corresponding author: Greg C. Roberts PI: Gregory C. Roberts Title: Research Scientist Affiliations: University of California San Diego - Scripps Institution of Oceanography and Centre National de la Recherche Scientifique Email: gcroberts@ucsd.edu; roberts.gregc@gmail.com ORCHID: 0000-0002-3636-8590 Address: 8861 Shellback Way / Keck OAR, Room 232, La Jolla CA 92093 1.0 Data Set Overview Abstract: These measurements are part of the ESCAPE campaign coordinated by Pavlos Kollias (Stonybrook) and Greg McFarquhar (Univ. Oklahoma). The main objective of the ESCAPE experiment is to improve our understanding of aerosol-cloud interactions in an urban environment. Two miniaturized cloud condensation nuclei (CCN) instruments (SIO) and a commercial DMT CCN instrument (NRC) were onboard the NRC Convair 580 to measure horizontal and vertical spatial variability of CCN number concentration CCN spectra and aerosol hygroscopicity. A total of 13 research flights were flown with the CCN instruments. Time of Interest - 2022/05/31 to 2022/06/17 Area of Interest - Houston, TX USA 2.0 Instrument Description: CCN measurements were performed with a miniature continuous-flow stream-wise thermal gradient chamber and a commercial DMT CCN instrument, which measures the concentration of activated CCN over a range of supersaturations (Roberts and Nenes, 2005). One CCN counter operated at constant flow and constant temperature gradient to produce a fixed supersaturation at 1Hz. The internal pressure of the CCN chamber was maintained at 400 or 600 mbar. The miniature CCN instruments each weigh ca. 2 kg, measure 20 x 20 x 10 cm (length, height, width), and consume ca. 50 W. General Dataset Description - CCN measurements were collected on the NRC Convair 580 during the ESCAPE field experiment. Three CCN counters were used: ca. 0.05% (SIO); 0.4 (NRC); and 0.9% (SIO) SS at 1 Hz. 3.0 Data Collection and Processing: Data was collected continuously with all CCN counters at a rate of 1 Hz. To improve the signal to noise ratio, measurements are averaged in 3 second increments. 4.0 Data Format: The data files represent 3 second averages and are presented in space-delimited ASCII format for the preliminary data. The columns represent: 1 Day_of_Year (UTC) 2 Cabin_CPC (/cc) 3 NCCN_1 (/cc) 4 SS_1 (%) 5 Amb_Press_1 (mbar) 6 Int_Press_1 (mbar) 7 NCCN_2 (/cc) 8 SS_2 (%) 9 Int_Press_2 (mbar) 10 NCCN_3 (/cc) 11 SS_3 (%) 12 Amb_Press_3 (mbar) 13 Int_Press_3 (mbar) Data Frequency - 3 second averages (0.333 Hz) Data Spatial Type - The preliminary data files are in ASCII space delimited format. File Names - RF01_CPC_CCN_ESCAPE_2022.DAT RF02_CPC_CCN_ESCAPE_2022.DAT RF03_CPC_CCN_ESCAPE_2022.DAT RF04_CPC_CCN_ESCAPE_2022.DAT RF05_CPC_CCN_ESCAPE_2022.DAT RF06_CPC_CCN_ESCAPE_2022.DAT RF07_CPC_CCN_ESCAPE_2022.DAT RF08_CPC_CCN_ESCAPE_2022.DAT RF09_CPC_CCN_ESCAPE_2022.DAT RF10_CPC_CCN_ESCAPE_2022.DAT RF11_CPC_CCN_ESCAPE_2022.DAT RF12_CPC_CCN_ESCAPE_2022.DAT RF13_CPC_CCN_ESCAPE_2022.DAT 5.0 Data Remarks - AS the CCN instruments have been installed behind the CVI, the data has been filtered (NaN) for periods when the CVI was turned on. Also, the data has been filtered for periods of the flight that are less than the internal pressure setpoint (either 400 or 600 mbar). \ Operating conditions for the CCN instruments during the campaign CCN (SIO) dT13,F220,P600 : 0.91 % SS dT13,F220,P400 : 0.73 % SS CCN (SIO) dT6.4,F100,P600 : 0.048 % SS dT5.3,F100,P600 : 0.035 % SS CCN (NRC) dT10.05,F500,P600 : 0.23 % SS dT5.9,F500,P600 : 0.12 % SS dT12.81,F685,P600 : 0.41 % SS Note that the data is preliminary and will be updated until the final data set is published (June 2023). Data restrictions - The CCN data will be available for public use when at the same time the rest of the ESCAPE data is available, though we request users contact: Greg Roberts (gcroberts@ucsd.edu; roberts.gregc@gmail.com). Digital Object Identifier (DOI) - T o be generated. GCMD Keywords - Cloud Condensation Nuclei (CCN), Condensation Nuclei (CN), Aerosol Clouds, ESCAPE 6.0 References - Roberts, G. C. and Nenes, A.: A continuous-flow streamwise thermal-gradient CCN chamber for atmospheric measurements, Aerosol Sci. Technol., 39, 206 221, https://doi.org/10.1080/027868290913988, 2005