Cross-polarized photon yield, beam attenuation coefficient, and fluorescence data derived from optical particle sensors deployed during casts of the GTC rosette on the GP17-OCE R/V Roger Revelle (RR2214) cruise Dec 2022 - Jan 2023

This data set was derived from optical particle sensors deployed during casts of the GEOTRACES Trace Metal Carousel (GTC) as part of the GEOTRACES GP17-OCE Expedition from the south Pacific gyre to Southern Ocean (R/V Roger Revelle RR2214). Data files are provided containing data for the 0-500 meter depth interval and also for the full water column. Data include measures of particle birefringence photon yield (units of parts per million per meter) and particle beam attenuation coefficient (units of per meter). 

The two PIC sensors (PIC010, and PIC011) used in this study have been extensively documented (Bishop et al. 2022). Briefly, the sensors are built on a digital WETLabs C-star 25-centimeter pathlength 6000-meter rated transmissometer. A 660-nanometer laser replaced the transmissometer's LED light source. High crossing efficiency polarizers were externally mounted to both source and receiver windows; the source polarizer is aligned with the plane of polarization of the laser and the receiver polarizer is crossed to minimize transmission of the direct beam. As light from the primary beam encounters birefringent particles, its plane of polarization is rotated and the sensor receives a signal. Details of methodology are included in Bishop et al., 2022 (doi: 10.3389/frsen.2022.837938).