Good morning/afternoon/evening, Using R, I am trying to calculate stream function (psi) and velocity potential (phi) from both 2D zonal (u) and meridional wind (v). I Stream function The stream function can be obtained from the vorticity (vorticity): vorticity = curl(u,v) or in other terms:? vorticity?= dv/dx - du/dy + u tan(th)/rad? This second approach is easily done using the function 'grad' in 'oce' package. Thus, the stream fuction is obtained solving the following Poisson equation (1): laplacian(psi) =?vorticity (1) or: div grad (psi) =?vorticity II Vorticity The vorticity can be obtained from the divergence (divergence): divergence?= div(u,v) or in other terms:? divergence?= du/dx + dv/dy - v tan(th)/rad? This second approach is also easily done using the function 'grad' in 'oce' package. Thus, the vorticity is obtained solving the following Poisson equation (2): laplacian(phi) =?divergence (2) or: div grad (phi) =?divergence Is there a way to solve both Poisson equations (1) and (2) in R? Best Regards, Pascal Oettli