Solar radiation atmospheric effects

The negative temperature anomaly in the 1992-93 has been explained as that the massive aerosol loading in the atmosphere due to the eruption of the Pinatubo Mountain in July 1991 causes the worldwide cooling at the sxrrface by strong reflectance of solar radiation. This effect could induce the ocean sirrface temperatxure drop, which in turn help uptake of the CO2 [1]. However,... 

The sun radiates approximately as a blackbody, with an effective temperature of about 6000 K. The total solar flux is 3.9 x 10 W. Using Wien s law, it has been found that the frequency of maximum solar radiation intensity is 6.3 x 10 s (X = 0.48 /rm), which is in the visible part of the spectrum 99% of solar radiation occurs between the frequencies of 7.5 X 10 s (X = 4/um) and 2 x 10 s (X = 0.15/um) and about 50% in the visible region between 4.3 x 10 s (X = 0.7 /rm) and 7.5 X 10 s (X = 0.4 /Ltm). The intensity of this energy flux at the distance of the earth is about 1400 W m on an area normal to a beam of solar radiation. This value is called the solar constant. Due to the eccentricity of the earth s orbit as it revolves around the sun once a year, the earth is closer to the sun in January (perihelion) than in July (aphelion). This results in about a 7% difference in radiant flux at the outer limits of the atmosphere between these two times. 

Greenhouse effect The retention of heat by the earth and the atmosphere due to certain gases being transparent to incoming solar radiation but opaque to the longer-wave radiation back from the earth. 

The density of the atmosphere varies greatly from place to place, as does its composition and temperature. The average composition of dry air (air from which water vapor has been removed) is shown in Table 4.4. One reason for the nonuniformity of air is the effect of solar radiation, which causes different chemical reactions at different altitudes. The density of air also varies with altitude. For example, the air outside an airplane cruising at 10 km is only 25% as dense as air at sea level. 

An allotrope of oxygen, ozone, 03 (8), is formed in the stratosphere by the effect of solar radiation on 02 molecules. Its total abundance in the atmosphere is equivalent to a layer that, at the ordinary conditions of 25°C and 1 bar, would cover the Earth to a thickness of only 3 mm, yet its presence in the stratosphere is vital to the maintenance of life on Earth (see Box 13.3). Ozone can be made in the laboratory by passing an electric discharge through oxygen. It is a blue gas that... 

The greenhouse effect is a natural phenomenon whereby the earth s atmosphere is more transparent to solar radiation than terrestrial infixed radiation (emitted by the earth s surface and atmosphere). Consequently, the planet s mean surface temperature is about 33 K higher than the planet s radiative equilibrium temperature (the temperature at which the earth comes into equilibrium with the energy received from the sun). 

Fig. 17-1 The global climate system, (a) Energy fluxes, including incoming solar radiation, reflected radiation, emitted longwave radiation (from an effective altitude of ca. 6 km), and atmospheric and oceanic heat flux toward the polar regions, (b) The atmospheric circulation corresponding to part (a). Refer back to Fig. 7-4 and associated text for a discussion of the general circulation.

Carbon dioxide does not affect the energy input to the planet because CO2 is transparent to most of the incoming solar radiation. In contrast, CO2 is extremely effective at absorbing infrared radiation, so the energy output from the planet decreases when the amount of carbon dioxide in the atmosphere increases by even a small amount. 

Wood is an anisotropic material that undergoes uneven dimensional changes and, under extreme variations of environmental conditions, becomes distorted and warped (see Chapter 10). Exposed to the atmosphere, wood is also susceptible to the mechanical forces of wind and rain, and the effects of solar radiation the latter, in particular, causes discoloration initially, and then photochemical degradation, which often results in the wood s total decomposition. Wood is also prone to consumption by bacteria, fungi, insects, and rodent animals (Unger et al. 2001). 

The photodissociation of S02 into SO and O atoms is markedly different from the photodissociation of N02. The bond to be broken in the sulfur compound requires about 560kJ/mol. Thus, wavelengths greater than 2180 A do not have sufficient energy to initiate dissociation. This fact is significant in that only solar radiation greater than 2900 A reaches the lower atmosphere. If a photochemical effect is to occur in the S02-02 atmospheric system, it must be that the radiation electronically excites the S02 molecule but does not dissociate it. 

Greenhouse effect The warming of Earth s atmosphere as a result of the retention of solar radiation. This retention is possible because insolation absorbed by the land and ocean is radiated back to the atmosphere as IR energy. This energy is absorbed by atmospheric gases and then radiated from them as heat. 

Several limitations do exist. The mercnry vapor released into the atmosphere conld be transported to aquatic systems, creating problems for fish and ofher wildlife. Phyforemedialion is only effective at shallow depths since root density decreases with depth. The mobihty of contaminants also decreases with depth. In addition, phytoremediation is a slower process than alternative technologies, and cleanup often reqnires several growing seasons. Environmental factors, including soil type, water availability, temperature, nutrients, and solar radiation can also limit the success of phytoremediation. 

Atkinson, R., D. L. Baulch, R. A. Cox, R. F. Hampson, J. A. Kerr, M. J. Rossie, and J. Troe, Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry. Supplement V. IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry, J. Phys. Chem. Ref. Data, 26, 521-1011 (1997). Bordewijk, J. A., H. Slaper, H. A. J. M. Reinen, and E. Schlamann, Total Solar Radiation and the Influence of Clouds and Aerosols on the Biologically Effective UV, Geophys. Res. Lett., 22, 2151-2154 (1995). 

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