Re: [ferret_users] Using xbox and zbox to find total transport

[Ryo Furue <furue@xxxxxxxxxx>]

Hi James and Russ,

I think the version of SODA you are using is based on POP and grid cell centres are at the middle of the cell. So let Z(k) be the centre of cell k and ZB(k) be the base of the cell. We have all the Z(k) and set ZB(0) to zero

ZB(0) = 0
Z(k)=0.5*(ZB(k-1)+ZB(k))

=> ZB(k) = 2*Z(k)-ZB(k-1) for k=1...

Same answer from me. Although I don't know the SODA grid, ZB(0) = 0 is most likely correct. If so, you can solve our coupled equations as Russ shows above.

Note there may be partial cells involved which complicates transport calculations. There's also the free surface to consider. Also I think the results are interpolated from a mercator grid to evenly spaced in latitude so beware. I'd suggest contacting the original providers for further info.

I second. (In so doing, you can ask them to include the cell boundary information in the netCDF files they provide.)

I hope the SODA people interpolated the velocity field considering volume conservation. The free surface and partial cells can be a problem depending on the accuracy you pursue.

Cheers,

Ryo