In spherical coordinates on the sphere ( with the zenith angle,, and the azimuth, ) and polar coordinates on the plane, the projection and its inverse are
12.
The angle of a celestial body with the zenith is the " zenith angle " ( in astronomy, commonly referred to as the " zenith distance " ).
13.
When observing at a zenith angle \ zeta, the line of sight passes through an air column which is \ sec \ zeta times longer, producing a greater disturbance in the wavefront quality.
14.
A body s angular position can also be given in terms of " altitude ", the angle above the geometric horizon; the altitude h and the zenith angle z are thus related by
15.
The counts for AVHRR observations at a given solar zenith angle and corresponding MODIS reflectance, corrected for TWP, are then used to determine what AVHRR value would be provided it had the MODIS calibration.
16.
Cloud albedo varies from less than 10 % to more than 90 % and depends on drop sizes, liquid water or ice content, thickness of the cloud, and the sun's zenith angle.
17.
Excess light occurs at the top of canopies and on open ground when cloud cover is low and the sun's zenith angle is low, typically this occurs in the tropics and at high altitudes.
18.
The LP-80 calculates LAI by means of measuring the difference between light levels above the canopy and at ground level, and factoring in the leaf angle distribution, solar zenith angle, and plant extinction coefficient.
19.
An 8 mm fisheye lens, also made by Nikon, has proven useful for scientific purposes because of its equidistant ( equiangular ) projection, in which distance along the radius of the circular image is proportional to zenith angle.
20.
""'The Zenith Angle " "'is a science fiction novel by Bruce Sterling, first published in 2004, about a pioneering expert in computer and network security with a traditional World Trade Center.
