SUMMARY:
Data from the Surface Wave Instrument Float with Tracking (SWIFT) are calculated as 10-minute ensembles, every 12 minutes. All SWIFT results here have been reprocessed and averaged into 30 min intervals for wave comparison with British and WII wave buoys. The majority of SWIFT structures are processed into 30 min intervals (name followed by “_30min”) except for where only telemetry files were available, in which 10-min ensemble are sent at the top of each hour (these structure names are followed with “_reprocessed”)

30-minute intervals are made by processing into standard half-hourly bins (i.e. centered at :15 and :45) by averaging the 1st-3rd bursts of each each hour, and then the 3rd-5th of the hour (due to the original 12-minute sampling interval). I only include half-hourly averages where all 3 bursts are available, such that all resulting spectra have the same degrees of freedom.

DATA DESCRIPTION:
Data are stored in a single structure in Matlab.  The structure is a collection of individual structures, with data for each 30-minute ensemble.  Use square brackets to index all ensembles, i.e.: 

>> plot([SWIFT.time],[SWIFT.sigwaveheight],'x')

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.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.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.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

CODE:
Use plotSWIFT.m to plot time series and spectra for an entire SWIFT record

More code and documentation can be found in CruiseShare/SWIFTdata_processed/Code_and_documentation