Multi-platform-based operating schemes of DOCARS and the performance in sea trials

A newly developed system called deep ocean compact autonomous Raman spectrometer (DOCARS) can be deployed on various underwater observation platforms. To meet the diversity requirement of the underwater observation platform and solve the matching problem of the working modes of the deployed instrument, two operation schemes were developed for DOCARS on the basis of deployment conditions and specific applications to function as either a benthic instrument node or a chemical sensor. Several peripheral units were operated in the instrument-node scheme. In another scheme, DOCARS operated only as a Raman spectrometry-based sensor. In sea trials in 2009, the first developed DOCARS, which operated as an instrument node, was mounted on the framework of a Seabird water sampler. The Raman spectra from the releasing samples and the monitoring images of performance were obtained. In the summer of 2015, the upgraded DOCARS was deployed on the remotely operated vehicle (ROV) Faxian, performing well as a chemical sensor with a detection rate of 1 Hz. Depth profiles of Raman spectra were received along the ROV's moving path on its four dives. The sea trials prove the effectiveness and stability of the two operation schemes on specific platforms.