Backward particle trajectories used to estimate the pathways of settling aggregates measured at stations N, HG and EG in Fram Strait

To investigate the pathways of settling aggregates in ice-covered and ice-free regions in Fram Strait, we used a Lagrangian particle tracking algorithm and computed backward particle trajectories. Particles were advected with daily averaged model velocities from the ocean-sea ice model FESOM. The computation of backward particle trajectories was performed for three stations, N, HG and EG. Experiments with three different sinking velocities per station were conducted (N: 20, 52 and 60 m/day; HG: 20, 29 and 60 m/day; EG: 20, 52, 60 m/day). In each of the experiments, particles were released once per day during the year 2016 above the sea floor and tracked until they reached the surface. Considering the 9 experiments (three stations and three settling velocities), altogether 3285 trajectories were calculated. A time step of 30 min was used for the trajectory calculation, and thus 48 positions per day and corresponding temperature and salinity values were stored.