The UiB Optics group participated with one instructor (Daniel Koestner) and one master student (Ole Høydal) in the Fram Strait 2024 cruise (13–28 August) led by the Norwegian Polar Institute. This cruise was part of a long term (~30 year) monitoring program along the Fram Strait and typically includes the deployment and retrieval of moorings, and sea ice stations. This is a dynamic and hydrographically interesting region where the eastern portion includes warm Atlantic water feeding into the Arctic Ocean and the western portion contains south-flowing cold polar water.
The Optics group is involved in development and application of tools to study organic carbon production and export through analysis of particle concentration, composition, and size distribution. Besides the training and collection of data for master Student Ole Høydal, the work had three main objectives: (1) Measure optical properties, (2) Measure particulate properties, and (3) To build and validate inverse-optical algorithms aimed at estimating biogeochemically relevant parameters from optical measurements.
In preparation for the cruise, Ole designed, troubleshooted, improved, and built an instrument cage to contain and safely deploy necessary optical instruments up to 500 m depth. The optical package consisted of an RBR Concerto CTD.PAR.Tridente (temperature, salinity, depth, photosythentically available radiation, backscattering at 700 nm and ~120º, and chlorophyll-a and DOM fluoresence) and a LISST-200X (near-forward scattering with 36 detectors ~0.04–12º and narrow beam transmission at 660 nm). Sensors were placed appropriately in cage so that down and upcasts would be free from obstruction.
