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	Lagrangians analys av drifter	Akustisk Dopplerströmningsmätare	Geostrofisk hastighet
Ämnesområde	Oceanografi	Oceanografi	Oceanografi
Familj	Process / pipeline	Process / pipeline	Process / pipeline
Ursprungsår	1985	1983	1942
Upphovsperson	Robert Davis	RD Instruments	Harald Sverdrup
Typ	instrumental	instrumental	theoretical-method
Ursprungskälla	Davis, R. E. (1985). Drifter observations of coastal surface currents during CODE: The method and descriptive view. Journal of Geophysical Research, 90(C3), 4741-4755.	RD Instruments. (1996). Acoustic Doppler Current Profiler Principles of Operation. A Practical Primer. RD Instruments Technical Note.	Sverdrup, H. U., Johnson, M. W., & Fleming, R. H. (1942). The Oceans: Their Physics, Chemistry, and General Biology. Prentice-Hall.
Alias	Lagrangian Tracking, Drifter Analysis	ADCP	Geostrophic Current, Thermal Wind Equation
Närliggande	3	3	3
Sammanfattning	Drifter Lagrangian analysis tracks the motion of water parcels using surface drifters (buoys with attached drogues) to measure ocean currents directly. Developed by Robert Davis in the 1980s, this method provides direct observation of water parcel trajectories and enables estimation of eddy diffusivity, transport pathways, and mixing. Drifter data complement Eulerian (fixed-point) observations by capturing the Lagrangian perspective of fluid motion.	The Acoustic Doppler Current Profiler (ADCP) is an instrument that uses Doppler-shifted acoustic backscatter to measure water velocity profiles along a vertical profile. Developed by RD Instruments in the 1980s, it has become the standard method for high-resolution current profiling in oceanographic research. ADCPs provide unprecedented spatial and temporal resolution of ocean circulation patterns.	Geostrophic velocity is the current driven by balance between the pressure gradient force and the Coriolis force, derived from the thermal wind equation. In most of the ocean away from the equator and coastal boundaries, geostrophic balance is an excellent approximation to the actual flow. Developed by Harald Sverdrup and colleagues in the 1940s, geostrophic velocity calculation from hydrographic data enables estimation of ocean currents without direct current measurements.