DOI: 10.5061/dryad.jdfn2z3j1
title: microSWIFT ocean surface wave data

description: Measurements of ocean surface waves are provided from microSWIFT buoys.
 Measurements include both bulk parameters (significant wave height, peak
 wave period, dominant wave direction) and spectral parameters (scalar
 spectra and normalized directional moments). Ancillary measurements, such
 as ocean temperature and salinity, are included when available. This
 dataset combines measurements from microSWIFT buoys deployed across many
 projects, spanning many times and locations. This unified dataset is
 intended to provide an ongoing single location for microSWIFT buoy data
 that has passed quality control and quality assurance.  
description: The microSWIFT buoys are deployed to the ocean surface from
 vessels and aircraft. The buoys freely drift and record GPS velocity data
 at 4 Hz, which is then processed onboard to make standard wave data
 products (see related works). The processed results are transmitted to a
 shore-side server every hour using Iridium satellite network. The
 processed results are reviewed for non-physical wave results and to assure
 only in-water measurements are retained (as opposed to measurements on
 land, on the deck of a vessel, or inside an aircraft). 
description: # microSWIFT buoy data
 [https://doi.org/10.5061/dryad.jdfn2z3j1](https://doi.org/10.5061/dryad.jdfn2z3j1) microSWIFT buoys measure waves and other ocean surface parameters. Raw data are collected in "bursts" which are processed onboard the buoy to produce standard wave products. An overview of the SWIFT program is at [http://www.apl.washington.edu/SWIFT ](http://www.apl.washington.edu/SWIFT) The buoys are described in the following publication:   Thomson, J., P. Bush, V. C. Contreras, N. Clemett, J. Davis, A. de Klerk, E. Iseley, E. J. Rainville, B. Salmi, and J. Talbert,  Development and testing of microSWIFT expendable wave buoys,** ***Coastal Engineering Journal*, 2023.  [https://doi.org/10.1080/21664250.2023.2283325](https://doi.org/10.1080/21664250.2023.2283325)   ## Description of the data and file structure There is a separate data file for each buoy and for each mission, with a naming convention "buoyID_missionname_missiondate" Date files are provided in both netCDF and Matlab format.\ The netCDF files use WMO standard variable names. The matlab files use data structures with the same results as following fields: SWIFT.CTdepth: depth below the ocean surface of the conductivity and temperature sensor (relates to SWIFT.watertemp and SWIFT.salinity) SWIFT.ID: buoy serial number SWIFT.lat: latitude in decimal degrees. This is the postition at the end of the wave burst. SWIFT.lon: longitude in decimal degrees. This is the postition at the end of the wave burst. SWIFT.peakwavedirT: wind direction, in degrees FROM North SWIFT.peakwaveperiod: peak of period of wave spectra SWIFT.replacedvalues: number of raw data points (out of 8192) that were removed by onboard despiking before calculating wave statistics. SWIFT.salinity: water salinity, in PSU, at 0.2 m below the surface. This is the average of 10 samples at the end of the wave burst. SWIFT.sigwaveheight: significant wave height, in meters SWIFT.time: UTC timestamp in MATLAB datenum format (serial days since 0 Jan 0000). This is the time at the end of the wave burst. SWIFT.watertemp: water temperature, in deg C, at 0.2 m below the surface. This is the average of 10 samples at the end of the wave burst. SWIFT.wavespectra.energy: wave energy spectral density, in m^2/Hz, as a function of frequency. SWIFT.wavespectra.freq: spectral frequencies, in Hz SWIFT.wavespectra.a1: normalized spectral directional moment (positive east) SWIFT.wavespectra.b1: normalized spectral directional moment (positive north) SWIFT.wavespectra.a2: normalized spectral directional moment (east-west) SWIFT.wavespectra.b2: normalized spectral directional moment (north-south) SWIFT.driftspd: speed in m/s that the buoy is drifting SWIFT.driftdirT: direction that the buoy is drifting, relative to true North The data should be viewed as time series.  In matlab  \&gt;&gt; plot([SWIFT.time],[SWIFT.sigwaveheight])  The linked codes on GitHub include plotSWIFT.m, which has more comprehensive data visualization for the .mat files.   The .nc  files can be viewed with Panoply.   ## Sharing/Access information Realtime and past telemetry from microSWIFT buoys is publically available via http queries to swiftserver.apl.washington.edu. Users are warned that telemetry data accessed directly are provisional and have not passed quality control / quality assurance. The http query syntax is described here: [https://github.com/SASlabgroup/SWIFT-codes/blob/master/Documents/SWIFT_telemetry_access.pdf](https://github.com/SASlabgroup/SWIFT-codes/blob/master/Documents/SWIFT_telemetry_access.pdf) And python package is available here:\ [https://github.com/SASlabgroup/microSWIFTtelemetry](https://github.com/SASlabgroup/microSWIFTtelemetry)\ There is also a Matlab function to pull telemetry directly in this repo \ [https://github.com/SASlabgroup/SWIFT-codes](https://github.com/SASlabgroup/SWIFT-codes)\ which requires the Matlab fixed-point designer toolbox to read half-float precision values.