Physical oceanographic instrumentation falls into five broad categories:

1. measurement systems tied to ships

2. anchored to the sea floor

3. propelled by ocean currents

4. based in space or on land

5. autonomously propelled

Lagrangian instruments (drifters and floats) generally depend on a ship (in some cases an aircraft) for transit to a study region. Moored instruments likewise require ships for transit.

Anchored measurementsMuch of the temporal structure of the ocean has been studied with instruments anchored to the sea floor recording physical variables at regular intervals over durations (most profitably) long compared to time scales of variability. The virtue of such measurements is that they describe purely temporal variability. Their drawback is that they are poor at resolving spatial variations unless they are sufficiently numerous, tambien el costo de transportarlo (por su naturaleza son masivas).

Subsurface moorings have routinely been set for periods as long as two years,

while wear on mooring components due to surface wave action have limited the reliable life of surface moorings to 6 months.

Problemas:

Arrastre a profundidades diferentes (errores de medicion, perdida de equipo)

Deterioro de los equipos

(6 meses a 5 m en el Mar Arabico)

(9 meses cerca superficie en el Pacifico)