Solar azimuth

Azimuth (Solar) - The angle between true south and the point on the horizon directly below the sun. 

The solar azimuth to is the angle between south and the direction toward the sun in a horizontal plane ... 

Figure 9 Aerosol attenuation factor I) (A)= 1- F er (A)/ Fckjr (A) at 325 nm for nonabsorbing (triangles) and absorbing (diamonds) aerosols as a function of the TOMS Lambert-equivallent reflectivity (R-0.05)/0.9 (the true surface reflectivity Rj= 0.05). Solar zenith angle is 50°, satellite zenith angle 32° and azimuth 90°...

Figure 9.14. The hourly scan pattern of COBE, WMAP and Planck from left to right. In each panel the anti-solar direction is in the center, and plus signs denote the North and South ecliptic poles. An equiangular azimuthal projection is used. COBE scanned this area in one orbit of about 103 minutes, WMAP scans its pattern every hour, while Planck spends several hours integrating on one scan circle of radius 70° radius shown offset from anti-Sun by a 15° precession angle.

Solar geometry mode (2 = Air Mass) IMASS (zenith and azimuth, date/time/lat/long available)... 

In Section III the solar-radiation intensity and its transmission through the troposphere are discussed. The solar flux is tabulated as a function of wavelength, and its dependence on azimuthal angle and total ozone column density is discussed. 

FIGURE 3.5 Horizontal coordinates of the Sun 0Q = solar zenith angle h = altitude angle 0o = azimuthal angle. 

Based on spherical trigonometry, a relationship can be derived connecting the solar zenith angle and the azimuthal angle 0o to the sun declination A, the latitude , and the hour angle H ... 

Solar Azimuth - The angle between the sun s apparent position in the sky and true south, as measured on a horizontal plane. 

Fig. 2.11 Scheme of the geometry of irradiation 9 solar zenith angle, 2 solid angle, azimuth direction angle. 

Solar radiation has an uneven geographic and chronological distribution throughout the world due to solar azimuth, which varies with latitude and season, elevation and atmospheric conditions including cloud cover and pollution. 

In the temperate latitudes of 35 45°, scattering of solar radiation increases significantly due to the longer atmospheric path length resulting from latitude and lower solar azimuth. Clouds and atmospheric pollution and particulates result in decreased incident radiation. Above 45° latitude almost half of the incident solar radiation is diffuse scattered sky and not direct beam. 

Fig. 10.115. Relationship between the three principal methods of measuring the illuminance due to sunlight, skylight and daylight on the horizontal plane (H), the perpendicular plane (P) and the normal incident plane (N). Part (a) represents a perpendicular plane through a line OS, which is drawn from a point O on the earth s surface to the sun (S), intersecting the horizontal plane along a line CB. Part (b) represents the three-dimensional relationship and defines the terms solar azimuth (A), solar altitude (b) and solar zenith distance [2293].

As mentioned in Subsection 8.6.a, a determination of the emitted planetary power requires measurements of the spectrally integrated disk intensity over all directions, that is, over 47T steradians. Since thermal emission does not directly depend on the solar flux, calculations of the total thermal emission are simpler than those required to find the Bond albedo. It is sufficient to use the conventional latitude-longitude system. The coordinates of the direction towards the observer are 9 and (f>o, and those of the area element, da, are a and . However, to save ourselves cumbersome trigonometric transformations, we use the emission angle s and the azimuth angle t/r with reference to the subobserver point as coordinates of da. The full disk intensity at wavenumber v, which can be measured by a distant observer, is then... 

The solar flux crossing a horizontal plane depends on the Sun s elevation angle but is independent of azimuth. The infrared radiation held is always azimuthally symmetric. Therefore, because only fluxes contribute to heating rates, we are interested solely in azimuth-independent radiation fields in our analysis. By analogy with Eq. (2.5.10), the appropriate equation for describing the transfer of radiation in the visible channel is... 

---