Dear Ethan You are right, boundary variables are associated with coordinate variables. That is because you need to supply point coordinates as well as cell bounds. I think it is usually natural to regard both the extent of a cell and the coordinate of the point as aspects of the definition of the cell. Of course for extensive quantities, like accumulated precipitation, the cell bounds are more important, and the coordinate value is more arbitrary. I would argue that it is helpful to have different time coordinate variables for each of your data variables. They happen to have the same-size dimension in your example, but the bounds and coordinates don't correspond, and it could be confusing to share the time axes, when really they are not the same. If the time-coordinate is taken to be the middle of the interval, as people often do, the 3-h bounds have coordinates 1.5, 4.5, 7.5, ..., while the 6-h bounds have coordinates 3, 6, 9, ... These should not share a coordinate variable.
Best wishes Jonathan _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
