geocat.comp.gradient._rad_lat_wgs84#
- geocat.comp.gradient._rad_lat_wgs84(lat)#
The radius calculation for the wgs84 ellipsoid at a latitude uses a taylor series from.
\[radius = \sqrt{a^2 \cdot cos(lat)^2+b^2 \cdot sin(lat)^2}\]This returns the radius of the ellipsoid for a given latitude This is accurate to within floating point error.
Note
This doesn’t need to be a taylor series, though the taylor series is faster and a needed step for the _arc_lat_wgs84 function to avoid the elliptic integral
- Parameters:
lat (
numpy.ndarray
,xarray.DataArray
) – 2-dimensional dataset, of orthographic latitude coordinates- Returns:
gradients (
list
ofnumpy.ndarray
,list
ofxarray.DataArray
) – latitudinal radii calculated using th WGS84 geoid.
See also
Related NCL Functions: grad_latlon_cfd, gradsf, gradsg