A vertical profile is obtained by moving an instrument vertically through the water while recording data as a function of depth. For measurements of light, the instrument type and deployment method will determine whether the recorded data will be optimal for the science goal when the instrument is raised (the “upcast”) or lowered (the “downcast”). For example, with C-OPS and XRR profiling systems, the downcast will almost always yield superior data, and with sufficient data density that the upcast is often de-selected during data processing.