Instrument: AC 9
"The WET Labs AC-9 is a type of in-situ spectrophotometer that simultaneously determines the spectral transmittance and spectral absorption of water over nine wavelengths. The unit offers compact size, high precision, and excellent stability in providing a method for determining the absorption (a(l)) and beam attenuation (c(l)) coefficients. The AC-9 employs a 25-cm pathlength for effective measurement of the cleanest natural waters. The unit is also available in a 10-cm pathlength configuration." (more from WET Labs)
The WetLabs ac-9 instrument was part of the flow-through system for gathering a continuous record of phytoplankton in vivo fluorescence, variable flourescences and water absorption and attenuation. (from cruise W0005 cruise report)