second_derivative_y
- second_derivative_y(fs, mode='fdiff', poles_missing_values=False)
Computes the second meridional (from South to North) partial derivative of each field in
fs
in */m2 units.- Parameters
fs (
Fieldset
) – input fieldsetmode ({"fdiff", "felem"}, default: "fdiff") – specifies the computation mode (see below)
poles_missing_values (bool, default: False) – puts missing values at the poles when
mode
is “felem”.
- Return type
The numerical method to compute the derivative is based on the value of
mode
.When
mode
is “fdiff”:a second order finite-difference approximation is used
the output fields contain missing values at the poles
only works for regular latitude-longitude grids
the computations for a field f are based on the following formula:
\[\frac {\partial^2 f}{\partial y^2} = \frac{1}{R^2}\frac{\partial^2 f}{\partial \phi^2}\]where:
R is the radius of the Earth in m
\(\phi\) is the latitude
When
mode
is “felem”:a finite-element technique is used, and the first derivative operator is invoked twice
works with (regular and reduced) latitude-longitude and Gaussian grids
no missing values are allowed in
fs
!the computations are performed by using
regrid()
with the nabla=”scalar_gradient” option twice in a row
Note
See also
second_derivative_x()
,first_derivative_x()
,first_derivative_y()
andgradient()
.