Global Drifter Program
   HOME

TheInfoList



OR:

The Global Drifter Program (GDP) (formerly known as the Surface Velocity Program (SVP)) was conceived by Prof. Peter Niiler, with the objective of collecting measurements of surface ocean currents, sea surface temperature and sea-level atmospheric pressure using drifters. It is the principal component of the Global Surface Drifting Buoy Array, a branch of NOAA's Global Ocean Observations and a scientific project of the Data Buoy Cooperation Panel (DBCP). The project originated in February 1979 as part of the TOGA/Equatorial Pacific Ocean Circulation Experiment (EPOCS) and the first large-scale deployment of
drifter A drifter is a vagrant who moves from place to place without a fixed home or employment. Drifter(s) or The Drifter(s) may also refer to: Films and television Films * ''The Drifter'' (1917 film), an American film directed by Fred Kelsey * ''Th ...
s was in 1988 with the goal of mapping the tropical Pacific Ocean's surface circulation. The current goal of the project is to use 1250 satellite-tracked surface drifting buoys to make accurate and globally dense in-situ observations of mixed layer currents, sea surface temperature, atmospheric pressure, winds and
salinity Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
, and to create a system to process the data. Horizontal transports in the oceanic mixed layer measured by the GDP are relevant to
biological Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary in ...
and chemical processes as well as physical ones.Grodsky, Semyon A., Rick Lumpkin, and James A. Carton. "Spurious trends in global surface drifter currents." ''Geophysical Research Letters'' 38.10 (2011).


Drifters

SVP project drifter deployments began in 1979; the design continued to develop until reaching its current form in 1992.Lumpkin, R. and M. Pazos, 2006: Measuring surface currents with Surface Velocity Program drifters: the instrument, its data, and some recent results. Chapter two of Lagrangian Analysis and Prediction of Coastal and Ocean Dynamics (LAPCOD) ed. A. Griffa, A. D. Kirwan, A. J. Mariano, T. Ozgokmen, and T. Rossby. Each drifter consists of a spherical surface buoy tethered to a weighted nylon drogue that allows it to track the horizontal motion of water at a depth of 15 meters. If the drogue breaks off, the wind pushes the surface buoy through the water, creating erroneous current observations. A tether strain gauge has been added to monitor tension of the buoy-drogue connection to resolve this issue. The original drifters are heavy, bulky (40 cm diameter), and expensive relative to the newer "mini" drifters that are smaller, (30.5 cm diameter) cheaper, and lighter because the hull contains fewer batteries. The surface float contains alkaline batteries, a satellite transmitter, a thermistor for sub-skin sea surface temperature, and sometimes other instruments that measure pressure, wind speed and direction, or salinity. The drifters are deployed from research vessels, volunteer ships, and through air deployment. They typically transmit their data hourly and had an average lifetime of ~485 days in 2001. Presently, enough data is gathered to observe currents at a horizontal resolution of one degree (~100 km). Single drifters can b
tracked
with the name of the drifter.


Applications

The data from the GDP have been used by oceanographers to derive maps of lateral diffusivity and Lagrangian length- and time-scales across the Pacific. Other uses include studies of plastic accumulation the ocean, and climatological models that simulate equatorial ocean currents, as well as many others.


Organization and collaborators

The GDP consists of three components. The component at NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) manages deployments, processes and archives the data, maintains META files describing each drifter deployed, develops and distributes data-based products, and updates th
GDP website
The Lagrangian Drifter Laboratory at the Scripps Institution of Oceanography (SIO) leads the engineering aspects of the Lagrangian drifter technology, improves the existing designs, develops new drifters, manages the real-time data stream, including posting the drifter data to the Global Telecommunication System, supervises the industry, purchases and fabricates most drifters, and develops enhanced data sets. The third component is the manufacturers in private industry, who build drifters according to specifications. The GDP collaborates with partners from numerous countries including Argentina, Australia, Brazil, Canada, France, India, Italy, Republic of Korea, Mexico, New Zealand, South Africa, Spain, United Kingdom, and the United States.


References

{{Reflist Oceanography