Dear Andy

Thanks for these proposals.

> charnock_coefficient_for_surface_roughness_length_for_momentum_in_air
> sea_surface_wave_mean_square_slope

are consistent with existing names and look fine to me.

I don't quite understand these ones.
> magnitude_of_sea_surface_wave_[xy]_mean_square_slope
You are considering the slopes in the x- and y-directions separately i.e.
deta/dx and deta/y, where eta is sea surface height. Maybe _[xy]_slope would
be clearer, if that's right. If it's a mean square, it surely must be positive,
mustn't it? If so, I don't see why it needs magnitude_of.

Best wishes

Jonathan

----- Forwarded message from "Saulter, Andrew" 
<[email protected]> -----

> Date: Fri, 14 Sep 2018 12:20:57 +0000
> From: "Saulter, Andrew" <[email protected]>
> To: "[email protected]" <[email protected]>
> Subject: [CF-metadata] standard names for sea surface roughness variables
> 
> Hello everyone, hope you are all well.
> 
> I'd like to propose some new standard names for variables relating to sea 
> surface roughness please. The v0 suggestions are:
> 
> charnock_coefficient_for_surface_roughness_length_for_momentum_in_air
> Units: 1
> Coefficient value, based on the Charnock (1955) empirical expression for 
> deriving surface_roughness_length_for_momentum_in_air  over the ocean. The 
> surface called "surface" means the lower boundary of the atmosphere.
> 
> [Not for description text, but see also 
> http://glossary.ametsoc.org/wiki/Charnock%27s_relation]
> 
> 
> sea_surface_wave_mean_square_slope
> Units: 1
> Wave slope describes an aspect of sea surface wave geometry related to sea 
> surface roughness. Mean square slope describes a derivation over multiple 
> waves within a sea-state, for example calculated from moments of the wave 
> directional spectrum.
> 
> magnitude_of_sea_surface_wave_x_mean_square_slope
> Units: 1
> Wave slope describes an aspect of sea surface wave geometry related to sea 
> surface roughness. Mean square slope describes a derivation over multiple 
> waves within a sea-state, for example calculated from moments of the wave 
> directional spectrum. Magnitude of "x" indicates that slope values are 
> derived from vector components along the grid x-axis, with slope always 
> taking a positive value.
> 
> magnitude_of_sea_surface_wave_y_mean_square_slope
> Units: 1
> Wave slope describes an aspect of sea surface wave geometry related to sea 
> surface roughness. Mean square slope describes a derivation over multiple 
> waves within a sea-state, for example calculated from moments of the wave 
> directional spectrum. Magnitude of "y" indicates that slope values are 
> derived from vector components along the grid y-axis, with slope always 
> taking a positive value.
> 
> [My main concern with these latter variables, is the use of magnitude and 
> vector x/y descriptors. Hopefully the descriptive text explains this OK; 
> basically a negative slope makes no sense in the context in which the data 
> are derived and used, i.e. for surface roughness estimation]
> 
> Will look forward to the comments :)
> Cheers
> Andy
> 
> 
> Andy Saulter
> Surge, Waves and Metocean Projects Manager
> Met Office  FitzRoy Road  Exeter  Devon EX1 3PB
> Tel: +44 (0)1392 884703  Fax: +44 (0)1392 885681
> [email protected] http://www.metoffice.gov.uk
> 
> 

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