Read me file for .mat file of SWIFT data used in Smith et al., 2018, JGR-Oceans (Smith_et_al_2018_SWIFTdata.mat). File includes processed data from all SWIFT buoys deployed during the 10-14 Oct, also known as Wave Array 3. 
Contact for question: M. Smith mmsmith@uw.edu

SUMMARY:
Data from the Surface Wave Instrument Float with Tracking (SWIFT) v3 are calculated as 10-minute ensembles, every 12 minutes. SWIFTs 08 and 10 only have one 10-minute burst per hour, transmitted via Iridium, as the raw data was not recovered from the buoys. 

SWIFT measurements include either up or downlooking ADCP (measuring tke dissipation rate or velocity profiles, respectively), basic meteorological measurements, wave spectra and parameters, 0.5-m subsurface temperature and salinity. Also included are collocated measurements from the ship, as described in Smith et al., 2018, JGR-Oceans, including calculated variables. 

More documentation regarding SWIFTs can be found at http://faculty.washington.edu/jmt3rd/SWIFTdata/DynamicDataLinks.html

DATA DESCRIPTION:
Data are stored in a single structure in Matlab.  The structure is a collection of structures for each SWIFT, containing individual structures with data for each 3burst.  Use square brackets to index all ensembles for a SWIFT, i.e.: 

>> [SWIFT(1).SWIFT.sigwaveheight] to get all waves heights from the first SWIFT

The full variable list and units are as follows: 

SWIFT.uplooking.tkedissipationrate: vertical profiles of turbulent dissipation rate in W/kg (= m^2 / s^3) beneath the wave-following free surface.

SWIFT.uplooking.z: depth bins, in meters, for the tke dissipation rate profiles

SWIFT.downlooking.velocityprofile: vertical profiles of horizontal velocity magnitude, in m/s, relative to the float (not corrected for drift)

SWIFT.downlooking.z: depth bins, in meters, for the velocity profiles

SWIFT.winddirT: true wind direction, in degrees FROM North

SWIFT.winddirTstddev: standard deviation of true wind direction, in degrees

SWIFT.windspd: wind speed, in m/s, at 1 m height above the wave-following surface

SWIFT.windspdstddev: standard deviation, in m/s, of wind speed

SWIFT.time: UTC timestamp in MATLAB datenum format (serial days since 0 Jan 0000)

SWIFT.airtemp: air temperature, in deg C, at 1 m height above the wave-following surface

SWIFT.airtempstddev: standard deviation of air temperature, in deg C

SWIFT.airpres: air pressure, in atm

SWIFT.airpresstddev: standard deviation of air pressure, in atm

SWIFT.driftdirT: drift direction TOWARDS, in degrees True (equivalent to "course over ground")

SWIFT.driftdirTstddev: standard deviation of direction of SWIFT drift, in degrees True

SWIFT.driftspd: speed of SWIFT drift, in m/s (equivalent to "speed over ground")

SWIFT.driftspdstddev: standard deviation of speed of SWIFT drift, in m/s

SWIFT.sigwaveheight: significant wave height, in meters

SWIFT.peakwaveperiod: peak of period orbital velocity spectra (note convention is usually wave height spectrum)

SWIFT.peakwavedirT: wave direction at energy peak, in degrees FROM North

SWIFT.wavespectra.energy: wave energy spectral density, in m^2/Hz, as a function of frequency.  Note that this is derived from orbital motions and is thus insensitive to low-energy swell conditions.  The technique is best suited to measuring short wind waves. 

SWIFT.wavespectra.freq: spectral frequencies, in Hz

SWIFT.wavespectra.a1: normalized spectral directional moments

SWIFT.wavespectra.b1: normalized spectral directional moment

SWIFT.wavespectra.a2: normalized spectral directional moment

SWIFT.wavespectra.b2: normalized spectral directional moment

SWIFT.wavespectra.check: spectral check factor (the ratio of vertical to horizontal variance in buoy motion)

SWIFT.lat: latitude in decimal degrees

SWIFT.lon: longitude in decimal degrees

SWIFT.watertemp: water temperature, in deg C, at 0.5 m below the surface

SWIFT.salinity: water salinity, in PSU, at 0.5 m below the surface

SWIFT.puck: three color channels of a WetLabs puck flourometer (not used on these deployments)

SWIFT.ki: dissipation rate calculated using exponential decay of amplitude in space, see Rogers et al., 2016 JGR-Oceans for details

SWIFT.icecode: ice code based on images from SWIFT camera, see Rogers et al., 2016 JGR-Oceans for details and definitions

SWIFT.shipwindspd: collocated wind speed from ship, corrected to 10-m height [m/s]. see Persson et al., 2018 for details 

SWIFT.shipwinddirT: collocated wind direction from ship [degrees], see Persson et al., 2018 for details 

SWIFT.shipwatertemp: collocated composite water skin temperature from ship [deg C], see Persson et al., 2018 for details

SWIFT.shipsalinity: collocated salinity at ship intake (6.5 m depth), [PSU]

SWIFT.shipustar: collocated bulk friction velocity from ship [m/s], see Persson et al., 2018 for details

SWIFT.shipsensible: collocated sensible heat flux estimated from ship, see Persson et al., 2018 for details [W/m2]

SWIFT.shiplatent: collocated latent heat flux estimated from ship, see Persson et al., 2018 for details [W/m2]

SWIFT.shipnetflux: collocated net atmospheric flux estimated from ship, see Persson et al., 2018 for details [W/m2]

SWIFT.sw: collocated shortwave radiation estimated from ship, see Persson et al., 2018 for details [W/m2]

SWIFT.lw: collocated longwave radiation estimated from ship, see Persson et al., 2018 for details [W/m2]

SWIFT.shipiceconc: collocated visual estimate of sea ice concentration from ship [tenths]

SWIFT.shipicez: collocated visual estimate of sea ice thickness from ship [cm]

SWIFT.uCTD.tempprofile: collocated uCTD temperature profile from ship [deg C]

SWIFT.uCTD.salrofile: collocated uCTD salinity profile from ship [psu]

SWIFT.uCTD.potdensity: collocated uCTD potential density profile from ship 

SWIFT.uCTD.z: depth bins [m] for collocated uCTD profiles

SWIFT.MLD: depth of mixed layer [m] determined from collocated uCTD, as defined in Peralta-Ferriz and Woodgate, 2015

SWIFT.NSTM: depth of near-surface temperature maximum [m] determined from collocated uCTD, as defined in Jackson et al., 2010

SWIFT.OHC: upper ocean salt content determined from collocated uCTD, as defined in Smith et al., 2018, Eq.1

SWIFTS.S: upper ocean salt content determined from collocated uCTD, as defined in Smith et al., 2018, Eq.2
