Transmittance (Sea-Bird)

RBR standard instruments support the Sea-Bird transmissometers (C-Star).

sea bird
Fig. 78.    Transmissometers (Sea-Bird)

These sensors measure underwater light transmittance by projecting a collimated beam through an optical flow tube and quantifying its attenuation. As the loss of light occurs due to scattering and absorption, the resulting value reflects the concentration of organic matter suspended and dissolved in seawater.

Parameter Value

Wavelengths

410 / 465 / 520 / 650nm

Bandwidth

~10-12nm for 370nm
~20nm for all other wavelengths

Pathlength

25 or 10cm

Acceptance angle

~1°

Bandwidth

~10-12nm for 370nm
~20nm for all other wavelengths

Linearity

99% R2

Depth rating

600m (plastic), 6000m (aluminium)