laplacian
- laplacian(fs)
Computes the Laplacian of each field in
fs.The computations for a field f are based on the following formula:
\[\triangle f =\frac{1}{R^2 \ cos^2\phi}\frac{\partial^2 f}{\partial \lambda^2} + \frac{1}{R^2}\frac{\partial^2 f}{\partial \phi^2} - \frac{1}{R^2}tan\phi\frac{\partial f}{\partial \phi}\]where:
R: radius of the Earth
\(\phi\): latitude
\(\lambda\): longitude.
The derivatives are computed with a second order finite-difference approximation. The resulting fields contain missing values on the poles.
Warning
laplacian()is only implemented for regular latitude-longitude grids.