http://bolin.su.se/data/oden-ascos-2008-aerosol-stratification-1 Caroline Leck, Joseph Sedlar, Erik Swietlicki, Staffan Sjögren, Barbara Brooks, Sarah Norris Bolin Centre Database 2022 Datafile Atmosphere Aerosols Aerosol vertical profiling High Arctic Summer ASCOS Arctic boundary layer Arctic clouds Icebreaker Oden Earth science > Atmosphere Caroline Leck 2022-12-05T08:35:52+00:00 English 1 The Quality Controlled data are provided in one `xls` spreadsheet file and one matlab `mat` file. Additional material in the form of photographs taken from the helicopter and image files with graphs that illustrate the data is also provided along with a readme file in `pdf` format. The dataset contains the following items: * `ASCOS08_QCdata_072011.xls`: Data from the helicopter flights. See below for details. * `ASCOS08_QCdata_072011_heli.mat`: Data from the helicopter flights. See below for details. * `ASCOS08_Flight_Schedule_QC_072011.xls`: Flight schedule for the Quality Controlled data files. * `ASCOS_QC_Heli_graphs.zip`: Graphical representations (`png` files) of the data in `ASCOS08_QCdata_072011.xls`. * `ASCOS_PhotosHeliFlights.zip`: Photographs (`jpg` files) on ambient sampling conditions during the helicopter flight when available. * `ASCOS_Heli_readme.pdf`: Provides details on the aerosol and meteorological instrumentation and measurements. The files `ASCOS08_QCdata_072011.xls` and `ASCOS08_QCdata_072011_heli.mat` contain data from the helicopter flights during the period 10 Aug⁠ – ⁠7 Sept 2008. All data is given with 1 second time resolution. Columns labeled “mean” or “med” represent 11 seconds running mean/med values. Height was calculated using observed pressure and temperature. Data time is given in MatLab datenum format. Data entries labeled -99999 indicate missing data. The data are provided in two file formats, to enable use in either excel or matlab. The files include the following data columns: 1. time (YY-MM-DD Hour:Min:Sec). 2. lat (°): latitude 3. lon (°): longitude 4. w_e (0=west 1=east) 5. z (m): height 6. P_ptu (hPa): Pressure 7. P_ptu mean (hPa): Pressure 8. P_ptu med (hPa): Pressure 9. T_tc (Celsius): Temperature 10. T_tc mean (Celsius): Temperature 11. T_tc med (Celsius): Temperature 12. RH_ptu (%): Relative humidity 13. RH_ptu mean (%): Relative humidity 14. RH_ptu med (%): Relative humidity 15. WVmr_calc (gkg-1) : Water Vapor mixing ratio 16. WVmr_calc mean (gkg-1) : Water Vapor mixing ratio 17. WVmr_calc med (gkg-1) : Water Vapor mixing ratio 18. ucpc (particles by number per cm3, Diameters > 3nm) 19. ucpc_mean (particles by number per cm3, Diameters > 3nm) 20. ucpc_med (particles by number per cm3, Diameters > 3nm) 21. cpc (particles by number per cm3, Diameters > 14nm) 22. cpc_mean (particles by number per cm3, Diameters > 14nm) 23. cpc_med (particles by number per cm3, Diameters > 14nm) 24. clasp (particles by number per cm3, Diameters > 300nm) 25. clasp_mean (particles by number per cm3, Diameters > 300nm) 26. clasp_med (particles by number per cm3, Diameters > 300nm) ##### Details of the measurements For vertical and horizontal profiling of aerosol, trace gases and meteorological parameters, 70 flights, and about 40 hours of helicopter time, were performed. The aerosol particle size concentrations were measured at 1 Hz in several size ranges using two Condensation Particle Counters ((Ultrafine)UCPC diameters >3nm and CPC diameters >14nm) and an Optical Particle Spectrometer (CLASP): diameters >300nm). The meteorological mapping was performed (logged at 2-3 Hz) with Thermoelements and a T, P and RH sensor PTU300 (Vaisala, Finland). More details concerning the instrumental set up is given below. The helicopter was very successfully deployed but its inability to penetrate cloud meant restricted measurements to clear sky episodes. The ideal solution would have been to use an all-weather (de-iced) helicopter, which was unfortunately not possible. The helicopter was flown perpendicular to the wind direction to the ship, and turned slightly upwind before the return flight. This method was chosen in order to ensure unpolluted air to be sampled, as well as not to disturb the measurements onboard the ship. The air was sampled through an inlet isokinetically at helicopter air speed of 70 km/h, which the pilot maintained manually. Flights are labeled according to date [MMDD] and flight number [nr] for each day. Certain flight numbers for a particular day are not included for use, indicating that these flight data were either: 1) not quality-controlled because the flight was a reconnaissance rather than research flight; 2) instruments were not operational. A data logging system was implemented within the cabin of the helicopter for aerosol and meteorological profiling measurements. Measurements were logged onto the hard disk of a Lenovo Thinkpad X61s PC laptop via National Instruments data acquisition software LabVIEW. First hand draft graphs of each of the Quality Controlled flights together with real time photos, when available, are also attached. All flights (#70) Flight0804nr1, Flight0804nr2, Flight0804nr3, Flight0804nr4, Flight0804nr5, Flight0805nr1, Flight0805nr2, Flight0806nr1, Flight0806nr2, Flight0806nr3, Flight0807nr1, Flight0807nr2, Flight0807nr3, Flight0808nr1, Flight0809nr1, Flight0809nr2, Flight0810nr1, Flight0810nr2, Flight0810nr3, Flight0811nr1, Flight0815nr1, Flight0816nr1, Flight0817nr1, Flight0820nr1, Flight0820nr2, Flight0820nr3, Flight0820nr4, Flight0820nr5, Flight0821nr1, Flight0822nr1, Flight0824nr1, Flight0824nr2, Flight0824nr3, Flight0824nr4, Flight0824nr5, Flight0825nr1, Flight0825nr2, Flight0825nr3, Flight0826nr1, Flight0826nr2, Flight0826nr3, Flight0826nr4, Flight0827nr1, Flight0827nr2, Flight0827nr3, Flight0827nr4, Flight0828nr1, Flight0828nr2, Flight0828nr3, Flight0829nr1, Flight0829nr2, Flight0829nr3, Flight0830nr1, Flight0830nr2, Flight0830nr3, Flight0831nr1, Flight0831nr2, Flight0831nr3, Flight0831nr4, Flight0901nr1, Flight0901nr2, Flight0901nr3, Flight0901nr4, Flight0903nr1, Flight0904nr1, Flight0905nr1, Flight0905nr2, Flight0906nr1, Flight0907nr1, Flight0907nr2 Flights Quality Insured (#45) Flight0810nr3, Flight0815nr1, Flight0816nr1, Flight0817nr1, Flight0820nr1, Flight0820nr3, Flight0820nr4, Flight0820nr5, Flight0821nr1, Flight0822nr1, Flight0824nr1, Flight0824nr3, Flight0824nr4, Flight0824nr5, Flight0825nr1, Flight0825nr2, Flight0825nr3, Flight0826nr1, Flight0826nr2, Flight0826nr3, Flight0826nr4, Flight0827nr3, Flight0827nr4, Flight0828nr1, Flight0828nr3, Flight0829nr1, Flight0829nr2, Flight0829nr3, Flight0830nr1, Flight0830nr2, Flight0830nr3, Flight0831nr1, Flight0831nr2, Flight0831nr3, Flight0831nr4, Flight0901nr1, Flight0901nr2, Flight0901nr3, Flight0901nr4, Flight0903nr1, Flight0905nr1, Flight0905nr2, Flight0906nr1, Flight0907nr1, Flight0907nr2 ##### Roles of data creators Caroline Leck was overall responsible for planning and implementation of the helicopter flights and for the data evaluation and quality ensuarance of the aerosol observations. The meteorological observations were managed, evaluated and quality ensured by Joseph Sedlar. Erik Swietlicki was responsible for designing and setting up the aerosol instrumentation. Staffan Sjögren and Sarah Norris managed the aerosol observations. Barbara Brooks was responsible for one of the instruments that measured particles in the helicopter, but she was not present onboard during the expedition. ##### Related study The [Kupiszewski et al. (2013)](https://doi.org/10.5194/acp-13-12405-2013) study sheds light on the characteristics of Arctic aerosol particles and their vertical distribution throughout the lower atmosphere during a three-week period when the Swedish icebreaker *Oden* was anchored to a drifting ice floe, north of 87°. ##### Origin of the dataset The dataset was originally made available on 12 July 2011, under the title *ASCOS Helicopter profiling of aerosol and meteorological parameters*, to participants in the ASCOS expedition and their collaborators, on a website that is now obsolete. Original address: http://www.ascos.se/index.php?q=node/393