Angle between a line of sight and the solar beam

The angle \(\Theta\) between two directions given as (zenith, azimuth): $$\cos\Theta = \cos\theta_1\cos\theta_2 + \sin\theta_1\sin\theta_2\cos(\phi_1 - \phi_2).$$ For the single-scattering polarization model this is the relevant scattering angle (the degree of polarization peaks near \(\Theta = 90^\circ\)).

Usage

scattering_angle(view_zenith, view_azimuth, sun_zenith, sun_azimuth)

Arguments

view_zenith, view_azimuth

Viewing direction in degrees.

sun_zenith, sun_azimuth

Solar-beam direction in degrees (use refracted_solar_angle for the in-water zenith).

Value

Angle in degrees, [0, 180]. Vectorised over its arguments.

See also

underwater_polarization

Examples

scattering_angle(view_zenith = 90, view_azimuth = 0,
                 sun_zenith = 0,  sun_azimuth = 0)   # 90
#> [1] 90