Surface, solar

Chou, M. D., and W. Zhou, Estimation and Model Validation of the Surface Solar Radiation and Cloud Radiative Forcing Using TOGA COARE Measurements, J. Clim., 10, 610-620 (1997). 

Figurel. Ratio of surface solar radiation for 15 km visual range to that for 95 km visual range as a function of wavelength the 1 and 2 km labels indicate boundary layer heights (from figure 1 in Liu et. al. 1991)...

Censolar atlas, Mean values of solar irradiation on horizontal surface, Solar International H-World-Edition Progensa, 1993. 

Perez R., Seals R., Ineichen P., Stewart R., Meniccucci D., A New Simplified version of the Perez diffuse irradiance model for tilted surfaces. Solar Energy 1987 39 221-231. 

The absorption cross section of BrO is represented by a banded spectrum in the 290-380 nm range with the strongest absorption feature around 338 nm (Wahner et al., 4988). Values are temperature dependent. The lifetime associated with the photodecomposition of BrO is of the order of 20 seconds at the Earth s surface (solar zenith angle of 30°) (Cox et al., 1982). 

Fig. 2. The sea surface solar energy distribution and typical energies for bond dissociation.

Compounds that do not absorb light within the surface solar spectrum are also subject to photochemical modification through indirect or sensitized photoreactions. In this case, the ROS or intermediates produced by direct photoreactions of a lightabsorbing constituent such as CDOM can react secondarily with the nonabsorbing compounds. DMS and COS, two trace gases of some importance to the atmosphere, are thought to be destroyed and created, respectively, by sensitized photoreactions in marine surface waters. 

Figure 4 Spectral dependence of CO photoproduction rates with depth, plotted on a linear (B) and logarithmic (C) scale. Depths in (B) are (from top to bottom) surface, 0.5, 1, 1.5, and 2 m. Depths in (C) are (from top to bottom) surface, 0.5, 1, 1.5, 2, 4, 6, 8, and 10 m. These spectral dependencies were calculated using eqn [7], the wavelength dependence of the quantum yield for CO shown in Figure 3, and the CDOM absorption spectrum and surface solar irradiance shown in (A). The attenuation of irradiance down the water column in this spectral region was assumed to be only due to CDOM absorption, a reasonable assumption for coastal waters (see Figure 1). Note the rapid attenuation in production rates with depth in the UV-B, due to the greater light absorption by CDOM in this spectral region.

Figure 5 Spectral dependence of the photochemical flux with depth for CO2, CO, and COS. Fluxes with depth are from the surface to 0.25, 0.5, 1.0, 2.0, and 4 m, respectively (bottom spectrum to top spectrum). Below 4 m, increases in the flux are nominal. These spectral dependencies were calculated using eqn [10], the wavelength dependence of the quantum yields for CO2, CO and COS shown in Figure 3, and the surface solar irradiance shown in Figure 4A. CDOM is assumed to absorb all photons in this spectral region (see Figures 1 and 4).

A wide variety of substances with active chromophores at wavelengths found In the surface solar spectrum occur in natural waters. Some of these substances undergo direct photolysis, that Is a chemical change that results as a direct consequence of the absorption of photons by the substance. Conceptually, direct photoreactions are the simplest and usually the easiest type of process to study In natural waters. Since the reaction proceeds rapidly to products from the primary excited state manifold, the physical characteristics of the reactant s environment usually have only small effects on the reaction. Such reactions can often be studied In pure and/or relatively high concentrations of the reactant. 

Thus, the nature of solar radiation has innate problems that require means (heat stores, auxiliary energy source, control system, and large-surface solar collectors) for their solution, and so the investment costs are considerable. Obviously, a prerequisite to utilizing solar energy is economics and the need to achieve an acceptable rate of return. 

PM Driver. An electrochemical approach to the characterisation of black chrome selective surfaces. Solar Energy Mater 4 179, 1981. 

Energy from the Sun is absorbed both in Earth s atmosphere (see Fig. 2.37) and at Earth s surface. Solar heating is greatest near the equator, in the tropics, where the Sun s rays are nearly vertically incident. Tropical air becomes buoyant due to solar warming, rises, and spreads poleward as cooler air from the direction of the poles flows imder the warmer air toward the equator, in a manner analogous to large-scale ocean circulation (Section 2.2.5). Planetary-scale convection cells thus are created in each hemisphere, in both the atmosphere and the oceans, and serve to transport heat toward the poles. If Earth did not rotate, one might expect relatively simple convective flow of fluids to occur, as shown in Fig. 4.11. 

Most organic contaminants are capable of undergoing photolytic decomposition. Although the atmosphere attenuates solar radiation before it reaches the Earth s surface, solar radiation is generally sufficient to break bonds in many compounds at this surface. Phototransformation in soil impacts only those contaminants on the soil surface. However, in agricultural lands that are tilled, contaminants in the tilling horizon ( 15-20 cm) can be brought to the surface where photo-transformation can occur. Photo-transformations can result in relatively short half-lives (e.g., hours to days) for contaminants such as pesticides that are applied directly to crops or soil surfaces. 

Pinker, R.T. Zhang, B. Dutton, E.G., 2005 Do Satelhtes Detect Trends in Surface Solar Radiation , in Science 308 850-854. 

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