[ncl-talk] rotation angle attributes

[maxpalma at fastwebnet.it]

Hi, 

my problem is:

I have "surface_downward_y_stress" and "surface_downward_x_stress", components (
v and u) 

I know that u and v must be rotated together, and I usually write commands like 
these:

  SENO   = grid->AngleSN
  COSENO = grid->AngleCS	

  U  = UU(0,0,:,:) *COSENO(:,:) - VV(0,0,:,:)*SENO(:,:)  
  V  = UU(0,0,:,:) *SENO(:,:)   + VV(0,0,:,:)*COSENO(:,:)

because in the file "grid" I have the variables:

"AngleCS(Y, X) ;
  AngleCS:description = "Cos of grid orientation angle at cell center" ;

and 

"AngleSN(Y, X) ;
AngleSN:description = "Sin of grid orientation angle at cell center" ;


Well, now I don't have this kind of variable in the "coordinates" file.

How can I rotate the vectors without the variable that contains the rotation ang
les associated with the grid?

How can I rotate u,v components, from a grid, to earth coordinates?

I would be most grateful if you could give me also a practical examples

Best regards, 

Massimiliano