[CF-metadata] Sea water velocity

From: Jonathan Gregory <j.m.gregory>
Date: Fri, 2 Oct 2009 17:26:23 +0100

Dear St?phane

> Which standard name could we use for :
> - The direction of the radial sea water velocity
> - The radial-component of sea water velocity ?

What do mean by "direction"? Is that just a sign - inward or outward? We
don't currently have a standard name for this, but we do have many standard
names for Xward_sea_water_velocity, and also
  radial_velocity_of_scatterers_away_from_instrument:m s-1
so by analogy with these I would propose
  radial_sea_water_velocity_away_from_instrument:m s-1
which specifies the sign convention. If you prefer the opposite convention,
it could be
  radial_sea_water_velocity_towards_instrument:m s-1

> We also have an associated aproximation error for each sea water
> velocity measurement. Is there a suffix for that (eg.
> eastward_sea_water_velocity_error) ?

This is done by adding a modifier to the standard name. See CF 3.3, Appendix C
and 3.4.

> In our files, we also have a mask of valid data. Do we also need a
> standard name for that variable ?

Standard name are always optional, so you don't have to assign one. They are
useful if you want to identify the data for other users, of course. Possibly
you could do this by labelling the mask as a status_flag variable (App C).
A more usual way to supply the valid data mask is of course to use missing
data values in the data variable.

> And then, a filter is applied to the eastward and northword sea water
> velocity to remove the effect of the tide. It produces a residual
> nortward and eastward sea water velocity.
> How can we distinguish in the standard name that residual velocity
> from the previous one ?

We would need a new standard name for those, I think. Would
  east|northward_sea_water_velocity_assuming_no_tide:m s-1
indicate what you meant? We often using assuming_X to indicate a recalculation
without some effect e.g. assuming_clear_sky.

Cheers

Jonathan
Received on Fri Oct 02 2009 - 10:26:23 BST