Shipboard radiometer with a PAR spectral response (400-700nm) designed to monitor surface irradiance during underwater light profile measurement. Hemispherical collector measuring 2-pi scalar irradiance.
For hydrocasts less than 1000m deep, a Biospherical Instruments QSP-200L4S underwater PAR sensor was attached to the CTD rosette. This sensor was linked to a surface PAR sensor on the ship (QSR-240).