Page 147 - Design of Solar Thermal Power Plants

132 3. GENERAL DESIGN OF A SOLAR THERMAL POWER PLANT

In addition, as the scattering effect of blue light is the strongest, a
clear sky is normally blue-colored.
3. Attenuation of atmospheric aerosols. Definition of atmospheric
aerosols: There is a large amount of solid and liquid particles in
the atmosphere with the size between 0.001 and 10 mm. They are
mostly dusts, soot deposits, water droplets, sized salts, organic
microbes, etc. As they are suspended in a gel state in the
atmosphere, these particles are normally called atmospheric
aerosols. As a major factor for influencing climate change,
atmospheric aerosols have aroused widespread attention from the
world scientific circle, which mainly include six categories of seven
types of aerosol particles. Sand dust aerosols or so-called mineral
aerosols are the main components of troposphere aerosols. China’s
sand dust aerosols mainly come from deserts in Xinjiang, Gansu,
Inner Mongolia, Loess Plateau and other arid and semiarid areas.
Recently, frequent sandstorms in North China have aroused broad
attention from both home and abroad. Sandstorm has turned into a
major environmental problem of the Earth. Sizes of atmospheric
aerosol particles are distributed on a very complex basis, and are
greatly influenced by climate variation as well. Maximum values of
concentration and dimension (diameter) of atmospheric aerosol
particles corresponding to different types of weather have been
listed in Table 3.2.
Optical wave attenuation of atmospheric aerosols includes
aerosol scattering and absorption (refer to Fig. 3.5). Sizes of the

TABLE 3.2 Physical Parameters of Haze, Cloud, and Precipitation

Type of Atmospheric
L3
Weather Type N/cm a max /mm Aerosols
Haze, M 100 3 Maritime or coastal
aerosols
Haze, L 100 2 Territorial aerosols
Haze, H 100 0.6 High-altitude or
stratosphere aerosols
Rain, M 100 3000 Drizzle or moderate rain
Rain, L 100 2000 Heavy rain
Hail, H 10 6000 Hail containing a large
number of small particles
Cumulus cloud, C.1 100 15 Cumulus cloud or stratus
cloud, mist

N refers to particle concentration, a max represents the maximum diameter of particle.