pyart.core.antenna_to_cartesian#

pyart.core.antenna_to_cartesian(ranges, azimuths, elevations, ke=None)[source]#

Return Cartesian coordinates from antenna coordinates.

Parameters:

• ranges (array) – Distances to the center of the radar gates (bins) in kilometers.

• azimuths (array) – Azimuth angle of the radar in degrees.

• elevations (array) – Elevation angle of the radar in degrees.

• ke (float, optional) – Effective radius scale factor

Returns:

x, y, z (array) – Cartesian coordinates in meters from the radar.

Notes

The calculation for Cartesian coordinate is adapted from equations 2.28(b) and 2.28(c) of Doviak and Zrnic [1] assuming a standard atmosphere (4/3 Earth’s radius model).

$$\begin{array}{r}\begin{array}{c}z=\sqrt{r^2+R^2+2\ast r\ast R\ast sin({\theta }_e)}-R\\ s=R\ast arcsin(\frac{r\ast cos({\theta }_e)}{R+z})\\ x=s\ast sin({\theta }_a)\\ y=s\ast cos({\theta }_a)\end{array}\end{array}$$

Where r is the distance from the radar to the center of the gate, ${\theta }_a$ is the azimuth angle, ${\theta }_e$ is the elevation angle, s is the arc length, and R is the effective radius of the earth, taken to be 4/3 the mean radius of earth (6371 km).

References