[{"name":"oden-ascos-2008-aerosol-stratification-1","title":"Vertical stratification of submicrometer aerosol particles measured during the high-Arctic ASCOS expedition 2008","summary":"The atmospheric thermodynamic structure and aerosol particle concentrations, in several size ranges, across a multitude of surface conditions over the Arctic Ocean pack ice, was profiled using a helicopter based onboard Swedish icebreaker Oden during the Arctic Summer Cloud Ocean Study (ASCOS) expedition in summer 2008.\r\n\r\nAerosol sources are known to be few in summer high Arctic while the cloud cover is generally at a maximum during this season. Until now, a large deficiency has been an inability to relate Arctic aerosol and cloud properties because of the difficulties in performing in situ measurements within the harsh Arctic environment.\r\n\r\nThe ultrafine particle (diameters between 3\u2060\u200a\u2013\u200a\u206015 nm) concentrations were typically a few hundred per cm\u00b3, but reached as high as 1500 cm\u207b\u00b3 and were often found within the shallow Arctic boundary layer, while occasional elevated concentrations were measured at higher altitudes. The accumulation mode particle concentrations were generally less than 1 cm\u207b\u00b3 within the well-mixed boundary layer. Such low levels can be explained by the presence of a moist boundary layer combined with in general weak local sources. In addition, largest accumulation mode numbers were found at and above former cloud tops.\r\n","citations":"Kupiszewski P, Leck C, Tjernstr\u00f6m M, Sjogren S, Sedlar J, Graus M, M\u00fcller M, Brooks B, Swietlicki E, Norris S, Hansel A (2013) Vertical profiling of aerosol particles and tracer gases over the central Arctic Ocean during summer. Atm Chem Phys 13: 12405\u2060\u200a\u2013\u200a\u206012431. doi:10.5194\/acp-13-12405-2013","comments":"##### Details of the measurements\r\nFor 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.\r\n\r\nThe 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.\r\n\r\nFlights 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.\r\n\r\nA 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.\r\nFirst hand draft graphs of each of the Quality Controlled flights together with real time photos, when available, are also attached.\r\n\r\nAll flights (#70)  \r\nFlight0804nr1, 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\r\n\r\nFlights Quality Insured (#45)  \r\nFlight0810nr3, 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\r\n\r\n##### Roles of data creators\r\nCaroline 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 Sj\u00f6gren 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.\r\n\r\n##### Related study\r\nThe [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\u00b0.\r\n\r\n##### Origin of the dataset\r\nThe 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.\r\n\r\nOriginal address: http:\/\/www.ascos.se\/index.php?q=node\/393","category":"Atmosphere","subcategory":"Aerosols","keywords":"Aerosol vertical profiling; High Arctic; Summer; ASCOS; Arctic boundary layer; Arctic clouds; Icebreaker Oden","scientist":"Caroline Leck, Joseph Sedlar, Erik Swietlicki, Staffan Sj\u00f6gren, Barbara Brooks, Sarah Norris","firstname":"Caroline","lastname":"Leck","address":"Department of Meteorology; Stockholm University\r\n","postalcode":"SE-106 91 ","city":"Stockholm","province":"","country":"Sweden","parameters":"Earth science > Atmosphere","location":"Ocean > Arctic Ocean","progress":"Completed","language":"English","project":"Arctic Summer Cloud-Ocean Study 2008 (Ascos). Support for this work was provided by the Swedish Research Council (VR) and the Knut and Alice Wallenberg Foundation and the DAMOCLES European Union 6th Framework Program Integrated Research Project. We also gratefully acknowledge the support from the Nordic Council of Ministers through their Arctic Cooperation Programme as well as the Nordic Top-level Research Initiative CRAICC (Cryosphere-atmosphere interactions in a changing Arctic climate). The Swedish Polar Research Secretariat (SPRS) provided access to the icebreaker Oden and logistical support.","publisher":"Bolin Centre Database","version":"1","constrains":"","access":""}]