Account for bottom depth in mode calculation.
Account for bottom depth in mode calculation.

Use WOA'13 depth mask for consistency. ETOPO values seem to be deeper
than what WOA uses.

Some water depths are deeper than woa.Z (this has been checked with
documentation, climatology is only available for 102 depth levels,
whereas there are 138 standard depth levels). In this case, I say that
all data is valid and assume ocean bottom is at bottom of profile.

dcherian/eq_waves,dcherian/eq_waves