Calculation of Gradient on ROMS data

[anurag.kumar]

Hi All,

I am doing some calculation to compute the geostrophic/thermal wind velocities but not able to get it correctly. I have the ROMS actual data on xi_rho and eta_rho grid. Can any one have idea how I can calculate it correctly? I need to calculate it on every vertical levels. For the information I have the actual ROMS data on sigma grid as well as on Z level (after converted it) both. I try to did some calculation from both data but not able to get it well. More specific I need to know the exact way to calculate the gradient on non-orthogonal curvilinear coordinate.

Thank you.

Anurag