This field type is a special version of the Drift output and is only available in case you have two or more cross-shore profiles in your simulation. The output file is typically used to assess the annual Q-a curve.
The number of time steps in the output file corresponds to the number of cross-shore profiles. Each time step in the time series file contains the time-integrated values for the entire simulation period along with the coastline orientation for the individual cross-shore profile.