Six-Hourly Interpolated Data


Please cite the following if you use these data: Lumpkin, Rick; Centurioni, Luca (2019). Global Drifter Program quality-controlled 6-hour interpolated data from ocean surface drifting buoys. [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/7ntx-z961. Accessed [date].



AOML receives position data computed from Doppler measurements from Argos-tracked drifters or from GPS installed in all Iridium and some Argos drifters. Historically, these data are irregularly distributed in time and they also contain erroneous positions and/or bad Sea Surface Temperature values, therefore not suited for many kinds of analysis or displays. The Drifter Data Assembly Center (DAC) at AOML applies quality control procedures to edit these data (position and temperature) and interpolates them to 6-hour intervals using an optimum interpolation procedure called kriging, which is commonly used for two and three-dimensional analyses. Some drifters have other sensors attached such as barometric pressure, salinity, wind speed and direction, but these data are stored in their raw form and kept in the archives, with no further editing done at the present time. See Hansen, D.V. and Poulain, P.M., 1996, [PDF] for a complete description of the quality controlled and interpolation procedures applied to the drifter data in this database. Hourly interpolated data is also available for a subset of the drifters.

Instructions for Dowloading the Entire Data Set

To access all data files (ASCII text ASCII compressed format):

Visit www.aoml.noaa.gov/ftp/phod/buoydata/ and select the desired file(s).


Or, using a secure FTP client, such as FileZilla, go directly to:

ftp://ftp.aoml.noaa.gov/pub/phod/buoydata/ and download the desired file(s).


Drifter data is broken into four smaller files for easy download.
Choose the desired file:

These data files are accompanied by Metadata Files (sometimes referred to as the "directory file") containing the initial transmission time and position, drogue off date, final time and position, death code, etc. for each drifter. The directory file for each dataset can be found below, using a secure FTP client, such as FileZilla.

buoydata_1_5000.dat.gz -- dirfl_1_5000.dat
buoydata_5001_10000.dat.gz -- dirfl_5001_10000.dat
buoydata_10001_15000.dat.gz -- dirfl_10001_15000.dat
buoydata_15001_MMMYY.dat.gz -- dirfl_15001_mmmyy.dat

Ragged Array files

The 6-hourly dataset through July 2022 is also available through FTP as single files containing contiguous ragged arrays, one for each data variable, as well as all metadata.
Two file formats are available, NetCDF and Apache Parquet.


Visit www.aoml.noaa.gov/ftp/pub/phod/buoydata/gdp_jul22_ragged_6h.nc for the NetCDF file.

Or, using a secure FTP client, such as FileZilla, go directly to:

ftp://ftp.aoml.noaa.gov/pub/phod/buoydata/gdp_jul22_ragged_6h.nc.


Visit www.aoml.noaa.gov/ftp/pub/phod/buoydata/gdp_jul22_ragged_6h.parquet for the parquet file.

Or, using a secure FTP client, such as FileZilla, go directly to:

ftp://ftp.aoml.noaa.gov/pub/phod/buoydata/gdp_jul22_ragged_6h.parquet.


Interpolated ERDDAP Database