Loading effect of a grid cell on itself, type scalar
(potential-like):
Approximation: Assuming a circular disk of the same size as a
spherical quadrangle.
Interpolation: Polynomial of order 4 to Greens function, applied on
logarithmic distance interval 0.003 to 1 degrees.
The assumed ocean grid resolution is 1o/16 × 1o/16.
Ordinate value is to be multiplied with tide height in metre.
Horizontal displacement derives from gradient operation on complete
field, d/dɸ, whence the ordinate's unit "radian".
Thus, the final, dimensioned result will be in metre units.