  Ship emissions can form linear cloud structures, or ship tracks, when
atmospheric water vapor condenses on aerosols in the ship exhaust. These
structures are of interest because they are observable and traceable examples
of marine cloud brightening, a mechanism that has been studied as a potential
approach for solar climate intervention. Ship tracks can be observed throughout
the diurnal cycle via space-borne assets like the Advanced Baseline Imagers on
the National Oceanic and Atmospheric Administration Geostationary Operational
Environmental Satellites, the GOES-R series. Due to complex atmospheric
dynamics, it can be difficult to track these aerosol perturbations over space
and time to precisely characterize how long a single emission source can
significantly contribute to indirect radiative forcing. We propose an optical
flow approach to estimate the trajectories of ship-emitted aerosols after they
begin mixing with low boundary layer clouds using GOES-17 satellite imagery.
Most optical flow estimation methods have only been used to estimate large
scale atmospheric motion. We demonstrate the ability of our approach to
precisely isolate the movement of ship tracks in low-lying clouds from the
movement of large swaths of high clouds that often dominate the scene. This
efficient approach shows that ship tracks persist as visible, linear features
beyond 9 hours and sometimes longer than 24 hours.
