In a scientific context, the zenith is the direction of reference for measuring the "'zenith angle "', the angle between a direction of interest ( e . g ., a star ) and the local zenith.
22.
In contrast to solar radiation management techniques, which would be most effective during the day time at lower latitudes, cirrus cloud thinning would be most effective at high latitudes and high solar zenith angles, where the background concentrations of aerosol are low.
23.
This is similar in operation to the zenith angle of 37 degrees, optimised for the Magellanic clouds, but because of the full range of azimuths and the celestial rotation, SALT has access to a good fraction of the sky available at the Sutherland site.
24.
Note that this function returns complex values and uses the physics convention for spherical coordinates where \ theta is the zenith angle ( angle from the positive Z-axis ) and \ phi is the azimuth ( counter-clockwise angle around the positive Z-axis ).
25.
Where \ widehat { \ mathbf { z } } is the axis of symmetry and \ theta is the angle between the position of the observer and the \ widehat { \ mathbf { z } } axis ( the zenith angle ), the solution for the potential will be
26.
With the assistance of a resident mathematician ( Dr . John Schell ), they studied solutions to this dilemma and subsequently developed the ratio of the difference of the red and infrared radiances over their sum as a means to adjust for or normalize the effects of the solar zenith angle.
27.
With \ zeta the zenith angle, v _ { \ mathrm { Wind } } ( z ) the windspeed as function of height and C _ n ^ 2 ( z ) the so-called atmospheric turbulence constant structure function, a measure of the turbulence strength as function of height.
28.
It was found that the ratio of calibration coefficients derived by Loeb [ 1997 ] and Rao and Chen [ 1995 ] are independent of solar zenith angle, thus implying that the NOAA-9-derived calibration curves provide an accurate relation between the solar zenith angle and observed reflectance over Greenland and Antarctica.
29.
It was found that the ratio of calibration coefficients derived by Loeb [ 1997 ] and Rao and Chen [ 1995 ] are independent of solar zenith angle, thus implying that the NOAA-9-derived calibration curves provide an accurate relation between the solar zenith angle and observed reflectance over Greenland and Antarctica.
30.
This ensures a full response when the solar radiation hits the sensor perpendicularly ( normal to the surface, sun at zenith, 0?angle of incidence ), zero response when the sun is at the horizon ( 90?angle of incidence, 90?zenith angle ), and 0.5 at a 60?angle of incidence.
