Ocean Heat Content variable names

At this point, we are calculating three variables related to the ocean heat content:

• ohc: 2d ocean heat content. Units: J

• ohcsum Total Ocean heat content Units: J

• ohcvmean Average Ocean heat content Units: J m-3

While working on issue #8 (closed) I have found that a0al provides an ocean heat content 2D variable in J m-2 that is not compatible with the one that we are computing. I assume that this version is more interesting in some cases (i.e plotting) while ours is more convenient for other uses (i.e compute totals or averages over basins).

Should we store both using different names or change the way we are calculating ours? Should we compute both versions (that will be quite inexpensive)?

What do you think @fmassonnet , @eexarchou?