Re: U,V at the Mixed Layer Depth

[Jonathan Callahan <callahan@xxxxxxxxxxxxx>]

Lars,

The relevant part of the on-line documentation is:

http://ferret.wrc.noaa.gov/Ferret/Documentation/Users_Guide/v50/chapter3.html#_1_96

Look at the examples there to understand what follows.

You need to use the @WEQ transform to create an "integration kernel" but
the @WEQ transform expects an axis (Z) where you have only a value.  So
we need to create a field on which the @WEQ transform can work.

The following should solve your problem

let depth = z[g=u]
let zero_at_mixed_layer = depth - mixed_layer_depth
let u_integrand = u * zero_at_mixed_layer[k=@weq]
let u_at_mixed_layer = u_integrand[k=@sum]

Notes:

1) Get the depth values associated with the grid of u
2) 'mixed_layer_depth' is 2D but will be automatically 'promoted' to 3D
(replicated along the Z axis of 'depth') to yield a 3D result
3) 'u_integrand' is a 3D field with missing values everywhere except
where 'zero_at_mixed_layer' = 0
4) We integrate because @WEQ does interpolation and can return 2 non-bad
flags (see the documentation).

I hope that solves your problem.


-- Jonathan Callahan


> Hello, everybody,
> 
> In my netcdf-file i have 3d fields of u,v and the 2d variable of the
> mixed layer depth.How can I get u,v at the mixed layer depth,
> without temerature and salinity fields.
> 
> Thanks for any answers.
> 
> Lars