Absorption of solar radiation

Jayaraman et al. (1998) measured the aerosol optical depth, aerosol size distribution, and the solar flux close to the coast of India, over the Arabian Sea, and then 

FIGURE 14-33 Calculated direct radiative forcing for the combination of black carbon and organic carbon from fossil fuel combustion. The numbers shown are the lower limits of the ranges included in each area. The boundaries of the regions are +10, +5, 2, 1, 0.5, +0.2, +0.1, and 0. Thus -5 represents the -5 to -10 W m 2 region, -2 represents the -2 to -5 W m 2 region, etc. (adapted from Penner el al., 1998). 

The presence of clouds can also affect the net light absorption by black carbon, indeed even more than for sulfate (Haywood and Shine, 1997 Haywood and Ra-maswamy, 1998 Liao and Seinfeld, 1998). For example, Liao and Seinfeld (1998) calculate that the net heating 

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In 1817, Josef Fraunhofer (1787-1826) studied the spectrum of solar radiation, observing a continuous spectrum with numerous dark lines. Fraunhofer labeled the most prominent of the dark lines with letters. In 1859, Gustav Kirchhoff (1824-1887) showed that the D line in the solar spectrum was due to the absorption of solar radiation by sodium atoms. The wavelength of the sodium D line is 589 nm. What are the frequency and the wavenumber for this line ... 

Most ozone is formed near the equator, where solar radiation is greatest, and transported toward the poles by normal circulation patterns in the stratosphere. Consequendy, the concentration is minimum at the equator and maximum for most of the year at the north pole and about 60°S latitude. The equihbrium ozone concentration also varies with altitude the maximum occurs at about 25 km at the equator and 15—20 km at or near the poles. It also varies seasonally, daily, as well as interaimuaHy. Absorption of solar radiation (200—300 nm) by ozone and heat Hberated in ozone formation and destmction together create a warm layer in the upper atmosphere at 40—50 km, which helps to maintain thermal equihbrium on earth. 

Obtain an expression for the absorptivity of solar radiation as a function of surface temperature and compare the absorptivity and emissivity at 300, 400, and 1000 K. 

The total emissivity of concrete a( 330 K is 0.89, whilst the total absorptivity of solar radiation (sun temperature --- 5500 K) at this temperature is 0.60. Use the data of Problem 9.31 for aluminium. 

Another family of feedbacks arises because the radical differences in the albedo (reflectivity) of ice, snow, and clouds compared to the rest of the planetary surface, which causes a loss of the absorption of solar radiation and thereby cools the planet. Indeed, the high albedo of snow and ice cover may be a factor that hastens the transition into ice ages once they have been initiated. Of course, the opposite holds due to decreasing albedo at the end of an ice age. As simple as this concept may appear to be, the cloud-albedo feedback is not easy to quantify because clouds reflect solar radiation (albedo effect) but absorb... 

In the mesosphere, from 50 to 85 km, the temperature again falls with altitude and vertical mixing within the region occurs. This temperature trend is due to the decrease in the CL concentration with altitude. At about 85 km the temperature starts to rise again because of increased absorption of solar radiation of wavelengths < 200 nm by 02 and N2 as well as by atomic species. This region is known as the thermosphere. 

FIGURE 3.13 Approximate regions of maximum light absorption of solar radiation in the atmosphere by various atomic and molecular species as a function of altitude and wavelength with the sun overhead (from Friedman, 1960). 

Solomon, S., R. W. Portmann, R. W. Sanders, and J. S. Daniel, Absorption of Solar Radiation by Water Vapor, Oxygen, and Related Collision Pairs in the Earth s Atmosphere, . /. Geophys. Res., 103, 3847-3858 (1998). 

There is also a significant correlation between temperature fluctuations in the lower stratosphere and fluctuations in total ozone. There are two sources of this correlation, radiative and dynamical (McCormack and Hood, 1994). Thus, increased ozone leads to increased absorption of solar radiation and increased heating. In addition, dynamical effects associated with vertical and meridional air motions also give a positive correlation between ozone and stratospheric temperature. For example, Randel and Cobb (1994) analyzed total column 03 and temperatures in the lower stratosphere from 1979 to 1992. Correlations between 03... 

While there thus appears to be evidence for apparent excess absorption of solar radiation by clouds, there is substantial controversy over whether this is indeed true absorption or whether there is some other explanation for the discrepancies (e.g., see Stephens and... 

If this excess absorption by clouds is ultimately shown to be a real phenomenon, then an increased cloud formation and extent due to anthropogenic emissions may alter the radiative balance of the atmosphere not only through increased reflectance but also through increased absorption of solar radiation. Such an effect could impact atmospheric temperatures, their vertical distribution, and circulation, as well as surface wind speeds and the surface latent heat flux (Kiehl et al., 1995). Hence establishing if this is truly excess absorption, and if so, its origins, is a critical issue that remains to be resolved. 

Y. Zhou, Absorption of Solar Radiation by Clouds Observations versus Models, Science, 267, 496-503 (1995). 

Cess, R. D., M. H. Zhang, Y. Zhou, X. Jing, and V. Dvortsov, Absorption of Solar Radiation by Clouds Interpretations of Satellite, Surface, and Aircraft Measurements, J. Geophys. Res., 101, 23299-23309 (1996b). 

Chylek, P., and J. Hallett, Enhanced Absorption of Solar Radiation by Cloud Droplets Containing Soot Particles in Their Surface, Q. J. R. Meteorol. Soc., 118, 167-172 (1992). 

King, M. D., L. F. Radke, and P. V. Hobbs, Determination of the Spectral Absorption of Solar Radiation by Marine Stratocumulus Clouds from Airborne Measurements within Clouds, J. Atmos. Sci, 47, 894-907 (1990). 

Kondrat ev, K. Y V. I. Binenko, and I. N. Melnikova, Absorption of Solar Radiation by Cloudy and Cloudless Atmosphere, Russ. Meteorol Hydro , No. 2, 8-15 (1996a). 

The photochemistry of halogenated methanes has been of great interest recently ever since it was recognized that chloromethancs in the stratosphere may release Cl atoms upon absorption of solar radiation and that Cl atoms so produced may catalytically decompose 03. 

Because the stratospheric temperature will most likely be affected by changes in 03 through changes in absorption of solar radiation and by the increase of C02 through... 

The necessary starting point for any study of the chemistry of a planetary atmosphere is the dissociation of molecules, which results from the absorption of solar ultraviolet radiation. This atmospheric chemistry must take into account not only the general characteristics of the atmosphere (constitution), but also its particular chemical constituents (composition). The absorption of solar radiation can be attributed to carbon dioxide (C02) for Mars and Venus, to molecular oxygen (02) for the Earth, and to methane (CH4) and ammonia (NH3) for Jupiter and the outer planets. 

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