Collocations of surface drifter and GlobCurrent (centered five-day) 15-m zonal and meridional velocity estimates

Date 2017-07-07
Temporal extent 1993-01-08 -2015-12-29
Author(s) Rick DanielsonORCID1
Affiliation(s) 1 : Nansen Environmental and Remote Sensing Center, Norway
DOI 10.17882/50225
Publisher SEANOE
Keyword(s) collocation, ocean current, drifter, GlobCurrent

GlobCurrent is an analysis that linearly combines the geostrophic and Ekman components. Drifters respond locally to a combination of geostrophic, Ekman, tidal, inertial, Stokes, and wind drift processes, including processes on scales smaller and faster than the GlobCurrent grid can resolve. Collocations of drifters (whose drogues move roughly with the 15-m current) and GlobCurrent (also at 15 m, with additional samples at daily intervals from two days before to two days after collocation) are included in this dataset.  Six-hourly drifter velocity has been estimated following Hansen and Poulain (1996). We restrict attention to drifters whose continuous drogue presence was confirmed by objective or subjective means (Rio et al. 2012, Lumpkin et al. 2013). The resulting geographic distribution for 1993-2015 (Fig. 1) yields more than eleven million drifter and GlobCurrent zonal and meridional velocity estimates. (A comparable number of drifters lost their drogues and, being more responsive to surface wind forcing, are omitted.)

Licence CC-BY
Utilisation Data are published without any warranty, express or implied. The user assumes all risk arising from his/her use of data. Data are intended to be research-quality and include estimates of data quality and accuracy, but it is possible that these estimates or the data themselves contain errors. It is the sole responsibility of the user to assess if the data are appropriate for his/her use, and to interpret the data, data quality, and data accuracy accordingly. Authors welcome users to address questions and report problems via the GlobCurrent website ( or directly to
Acknowledgments Data compilation was performed with funding from ESA. GlobCurrent data were obtained from and quality-controlled interpolated drifter observations from the NOAA AOML global drifter program website at
Sensor metadata

Collocations are of drifters and GlobCurrent zonal and meridional 15-m current components.  Data are 11519358 collocations between 1993 and 2015.  Data are written in the gzipped file as one collocation per line using the format statement "%10d %7.3f %8.3f %9.4f %9.4f %4d %4d %9.4f %9.4f %9.4f %9.4f %9.4f %9.4f %9.4f %9.4f %9.4f %9.4f".  The entries are, respectively,

date (yyyymmddhh)
T0      drifter     zonal      current (m/s)
T0      drifter     meridional current (m/s)
lat index on GlobCurrent grid  (-89.875:0.25:89.875)
lon index on GlobCurrent grid (-179.875:0.25:179.875)
T0-2day GlobCurrent zonal      current (m/s)
T0-2day GlobCurrent meridional current (m/s)
T0-1day GlobCurrent zonal      current (m/s)
T0-1day GlobCurrent meridional current (m/s)
T0      GlobCurrent zonal      current (m/s)
T0      GlobCurrent meridional current (m/s)
T0+1day GlobCurrent zonal      current (m/s)
T0+1day GlobCurrent meridional current (m/s)
T0+2day GlobCurrent zonal      current (m/s)
T0+2day GlobCurrent meridional current (m/s)

File Size Format Processing Access
Collocations of drifter and GlobCurrent (five-day centered) 15-m ocean current velocity components (1993-2015) 387 MB TEXTE Processed data Open access
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How to cite 

Rick Danielson (2017). Collocations of surface drifter and GlobCurrent (centered five-day) 15-m zonal and meridional velocity estimates. SEANOE.