[{"title":"Micrometeorological data from icebreaker Oden\u2019s foremast during the Arctic Ocean 2016 expedition","summary":"Air-sea fluxes and other micrometeorological variables derived from fast response (20 Hz) measurements of the 3-dimensional wind vector, temperature and humidity, and mean meteorological measurements using eddy covariance.\r\n \r\nThese are rare, direct measurements of the air sea exchange of momentum, sensible and latent heat from open water and sea-ice regions of the Arctic Ocean. They are key parameters in numerous processes, for example, determination of the surface energy balance.\r\n \r\nThe measurements are from instrumentation mounted on icebreaker Oden\u2019s foremast at approximately 20 m above sea level during the Arctic Ocean 2016 (AO2016) expedition to the central Arctic Ocean in August and September 2016. Eddy covariance fluxes are determined on 30-minute intervals.","citations":"","comments":"The instrumentation on the foremast consisted of a Gill R3 sonic anemometer, a LI-COR 7500 infrared gas analyser, an aspirated TRH sensor, an XSENS MTiG 3-axis inertial motion unit (managed by ICAS, University of Leeds). Other instrumentation included an LGR fast response greenhouse gas analyser installed at the base of the mast with an inlet drawing air at the top of the mast (managed by Department of Geological Sciences, Stockholm University).\r\n\r\nWind measurements were corrected for platform motion following Edson et al. (1998; Direct covariance flux estimates from mobile platforms at sea. J. Atmos. Ocean. Tech, 15, 547-562) and Prytherch et al. (2015: Motion-correlated flow distortion and wave-induced biases in air-sea flux measurements from ships. Atmos. Chem. Phys., 15, 10619\u201310629).\r\n\r\nWinds are measured relative to the ship. The ship acts to distort the wind speed and direction, increasingly so for winds away from bow-on. A computational fluid dynamics (CFD) model of airflow over Oden is used to correct the measured winds for wind directions within 150\u00b0 of bow on (Yelland et al. (2002) CFD model estimates of the airflow distortion over research ships and the impact on momentum flux measurements, J. Atmos. Ocean. Technol., 19, 1477\u20131499; Moat et al. (2015) Airflow distortion at instrument sites on the ODEN during the ACSE project, National Oceanography Centre, Southampton, UK, 114 pp., National Oceanography Centre Internal Document, 17). Winds are then adjusted to Earth frame using GPS measurements.\r\n\r\nThe majority of the fast-response instrumentation is measured at 20 Hz. Atmosphere-surface fluxes were determined from the fast-response measurements using eddy covariance.\r\n\r\nCO\u2082 and CH\u2084 flux and atmospheric concentrations will be published in separate data sets and are not included here.\r\n\r\nQuality control flagging follows Foken et al. (2012): Chapter 4 in Eddy Covariance: A practical guide to measurement and data analysis (eds. M. Aubinet, T. Vesala, D. Papale), Springer Atmospheric Sciences, and references therein: Foken and Wichura (1996) and Vickers and Mahrt (1997). Some of the code implementing these was adapted from the [Eddycalc](http:\/\/www.swissfluxnet.ch\/eddycalc\/html\/Eddycalc_LI7200.html) suite.\r\n\r\nData from the foremast are combined into a cruise-length file. The data are time-averaged to both 1-minute and 30-minute intervals. Flux data are not included in the 1-minute files.\r\n\r\nCoordinates (lat, lon) for the observations are not included in this dataset, but they are the same as in the [Weather data from MISU weather station during the Arctic Ocean 2016 expedition](https:\/\/bolin.su.se\/data\/ao2016-misu-weather).\r\n\r\nMore information about the Canadian-Swedish [Arctic Ocean 2016 expedition](https:\/\/polarforskningsportalen.se\/en\/arctic\/expeditions\/arctic-ocean-2016) is available from the Swedish Polar Research Secretariat.\r\n\r\n#### Version history\r\n\r\n##### Version 4.0\r\nCorrected error in the Monin Obukhov (MO) stability calculation where complex numbers had been introduced by bad wind data, resulting from icing.\r\n\r\n##### Version 3.0\r\nAll wind speeds and directions in processing and final data are now strict vector averages.\r\n\r\n##### Version 2.0\r\nInitial release.\r\n\r\n##### Version 1.0\r\nNot published.","category":"Atmosphere","subcategory":"Micrometeorology","keywords":"Micrometeorological data; Meteorology; Air-sea interaction; Eddy covariance; Arctic boundary layer; Arctic clouds; High Arctic; Arctic Ocean 2016; AO2016; AO16; ACAS; Oden","scientist":"John Prytherch, Michael Tjernstr\u00f6m, Ian Brooks","firstname":"John","lastname":"Prytherch","address":"Department of Meteorology (MISU); Stockholm University","postalcode":"SE-106 91","city":"Stockholm","province":"","country":"Sweden","parameters":"Earth science > Atmosphere","location":"Ocean > Arctic Ocean","progress":"Completed","language":"English","project":"Arctic Ocean 2016 expedition. These data were processed as part of the Arctic Climate Across Scales (ACAS) project, funded by the Knut and Alice Wallenberg Foundation. Project PI Michael Tjernstr\u00f6m (MISU).","publisher":"Bolin Centre Database","version":"4.0","constrains":"None","access":"Free"}]