Albedo, particle

Self-Feedback Effect Photochemistry Effect Smudge-Pot Effect Daytime Stability Effect Particle Effect through Surface Albedo Particle Effect through Large-Scale Meteorology Indirect Effect Semi-direct Effect... 

Clouds of Nonblack Particles The correction for nonblackness of the particles is complicated by multiple scatter of the radiation reflected by each particle. The emissivity . of a cloud of gray particles of individual surface emissivity 1 can be estimated by the use of Eq. (5-151), with its exponent multiplied by 1, if the optical thickness alv)L does not exceed about 2. Modified Eq. (5-151) would predict an approach of . to 1 as L 0°, an impossibihty in a scattering system the asymptotic value of . can be read from Fig. 5-14 as /, with albedo (0 given by particle-surface refleclance 1 — 1. Particles with a perimeter lying between 0.5 and 5 times the wavelength of interest can be handledwith difficulty by use of the Mie equations (see Hottel and Sarofim, op. cit., chaps. 12 and 13). 

Climate is often viewed as the aggregate of all of the elements of weather, with quantitative definitions being purely physical. However, because of couplings of carbon dioxide and many other atmospheric species to both physical climate and to the biosphere, the stability of the climate system depends in principle on the nature of feedbacks involving the biosphere. For example, the notion that sulfate particles originating from the oxidation of dimethylsulfide emitted by marine phytoplankton can affect the albedo (reflectivity) of clouds (Charlson et ai, 1987). At this point these feedbacks are mostly unidentified, and poorly quantified. 

Cloud albedo is calculated to be sensitive to the droplet population. Twomey (1977) showed theoretically that albedo is enhanced by the addition of particles to the atmosphere. 

To remove the essential oil from the peel of citrus fruits, the oil glands, which are located in the flavedo (the outer coloured portion of the peel), are ruptured by mechanical systems. The oil is washed away with a spray of water to produce an oil-in-water emulsion with small peel particles. To prevent absorption of the essential oil by the spongy albedo (the iimer white portion of the peel), this emulsion is passed through a screening device (finisher) of 0.5 to 0.7 mm in diameter, which removes the coarsest particles of the fruit peels [12]. 

The reflection spectrum of the atmosphere is a measure of the albedo of the planet (Figure 10.4) and, despite the strong methane absorption in the red, Titan s disc looks orange principally due to scatter from the surface of dense methane-hydrocarbon clouds. Scatter from aerosol particles within the thick clouds obscures the surface of the moon although the radar analysis reveals considerable Chapman layer structure within the atmosphere and some interesting surface features. 

Whether or not simultaneous changes in aerosol particles and clouds have indeed altered UV at the earth s surface is not clear. For example, Herman et al. (1996) have analyzed satellite data for ozone and reflectivity from 1979 to 1992 and conclude that over this period of time there was no significant trend in the UV albedo due to changes in clouds or aerosols. 

Because the single-scattering albedo depends sensitively on the imaginary part of the refractive index there has been keen interest in determining optical constants of atmospheric particles. These are used to calculate the important parameters in the heat balance problem for present and predicted aerosol... 

Comparison of telescopic spectra of asteroids (shown by dots and black curves) with meteorite spectra measured in the laboratory (gray curves). Spectral similarities can be used to estimate the compositions of asteroids and infer correlations. Because absolute reflectance (albedo) depends on particle sizes and packing in surface regoliths, it is permissible to translate asteroid spectra up or down in the diagram to obtain a match. 

Understanding the physical and chemical properties of marine aerosol particles is crucial because of the role these particles play in a number of atmospheric processes. Marine aerosols affect climate directly through scattering and absorption of radiation and indirectly as they can act as cloud condensation nuclei and thus influence the albedo of clouds. In addition, marine aerosol particles play an important role in the cycling of various elements through the atmosphere. 

The indirect climatic impact of aerosol at the ABL is determined by numerous interactions between aerosol and the dynamics of the microphysical and optical properties of clouds. The input to the atmosphere of anthropogenic aerosol particles functioning as CCN favors an increase in cloud droplet number density. As mentioned above, the related increase in the optical thickness and albedo of clouds, with their constant water content, was called the first indirect effect , which characterizes the climatic impact of aerosol. 

CCN). Changes in the concentrations of CCN may alter the cloud droplet concentration, the droplet surface reflectivity, the radiative properties of clouds (cloud albedo) (2), and hence, the earth s climate (8-101. This mechanism has been proposed for the remote atmosphere, where the radiative properties of clouds are theoretically predicted to be extremely sensitive to the number of CCN present (ID). Additionally, these sulfate particles enhance the acidity of precipitation due to the formation of sulfuric acid after cloud water dissolution (11). The importance of sulfate aerosol particles to both radiative climate and rainwater acidity illustrates the need to document the sources of sulfur to the remote atmosphere. 

Water balance models have frequently been used to examine the surface runoff from watersheds. Some of these models, focused more on climate change, are called Soil-Vegetation-Atmosphere Transfer Schemes (SVATs) (Vordsmarty and Peterson, 2000). These model simulations use different parameters such as vegetation cover, soil texture (different sizes of mineral particles), water-holding capacity of soils, surface roughness, and albedo (the fraction of light reflected by a body or surface), to make predictions on... 

Reflection phenomena in the atmosphere occur for wavelengths less than the particle size and are fairly independent of wavelength in this region. The term albedo is used to describe the reflective properties of surfaces and is defined by... 

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