Reflection, radiation scattering

The portion of the incoming radiation reflected and scattered back to space is the albedo. The albedo of clouds, snow, and ice-covered surfaces... 

This interaction leads to at least four (4) components, namely R- the radiation reflected, A- the radiation absoit>ed, T- the radiation transmitted, and S - the radiation scattered. A depiction of these interactions is given in the following diagram ... 

Complex processes are involved in transmittance and reflectance of scattered radiation, which are theoretically described by Schuster [4]. In an ideal scattering medium all fluxes of light can be summed up as components of two vectors. Vector I stands for the light flux in the direction of the incident light, and the vector J describes the light intensity in the antiparallel direction. With k, the absorption coefficient, and 5", the scattering coefficient, the two Schuster equations are as follows ... 

Sunblocks are opaque substances such as zinc oxide, titanium dioxide, and iron oxide that protect by forming a shield on the skin, which reflects and scatters incident radiation. In essence, sunblocks provide physical protection against sun exposure, including both visible and ultraviolet light. Sunscreens are substances that chemically absorb ultraviolet light in the top layer of the epidermis, protecting the underlying layers. 

The beam of the radiation passing through the studied object interact with the material that induces a certain scattering pattern of the reflected radiation detectable by the radiation sensors. This scattering is caused by the... 

Experimental spectra are usually presented as plots of the intensity of (absorbed, emitted, reflected, or scattered) radiation versus the photon energy (in eV), the wavelength (in nm) or the wavenumber (in cm ). Using Equation (1.1), useful interconversion equations between these different units can be obtained ... 

Spectra of solid samples are usually recorded in the units of reflectance (R) or percent reflectance (%/ ), which is analogous to percent transmittance in that reflectance equals the ratio of the reflected radiation to the incident radiation. With diffuse reflectance, the reflected signal is attenuated by two phenomena absorption (coefficient k) and scattering (coefficient s). Lollowing the Kubelka-Munk theory, these two coefficients are related to the reflectance of an infinitely thick sample, by... 

In diffuse reflection spectroscopy, the spectrometer beam is reflected from, scattered by, or transmitted through the sample, whereas the diffusely scattered light is reflected back and directed to the detector. The other part of the electromagnetic radiation is absorbed or scattered by the sample [124,125]. Changes in band shapes or intensity as well as signal shifts can be affected by morphological and physicochemical properties of the sample or combinations thereof (e.g., chemical absorptions, particle size, refractive index, surface area, crystallinity, porosity, pore size, hardness, and packing density [126]). Therefore, NIR diffuse reflection spectra can be interpreted in dependence of various physical parameters [127]. 

One can thus estimate the total light intensity incident on a given volume of air in the troposphere due to direct solar radiation, scattering, and reflection. The light absorbed in that volume can then be calculated... 

These sources are direction radiation from the sun, radiation scattered by gases and particles, and radiation reflected from the earth s surface. 

The light available to a molecule in air for absorption and photodissociation includes both direct and scattered and reflected radiation coming from all directions as described earlier and depicted in Fig. 3.16. The term actinic flux or spherically integrated actinic flux, denoted by F( A), is used to describe the total intensity of this light and is the quantity of interest in calculating kp. 

Backscatter Reflected or scattered radiation in the general direction of the source after it strikes matter (gas, liquid, or solid). 

B. Dimensional Stability Boroscope Miniaturized T.V. Microscope Radiation Reflectance or Diffraction Photocell (visible) X-ray diffraction U.V. reflectance spectroscope y-Ray back-scatter Scintillation read out Infrared reflectance Radiation emission Infrared scan Profilometer... 

How are the Laue condition and the Bragg condition connected In Fig. A.3 the wave vectors of the incident and outgoing radiation and the scattering vector are drawn for the Bragg reflection of Fig. A.l. We can conclude that for specular reflection, the scattering vector lattice plane. Its length is given by... 

Solids. Conventional near-infrared reflectance analyzers use a variety of methods to position the sample into the incident collimated beam and collect reproducibly the diffusely reflected radiation to measure the absorption which takes place in the body of the sample traversed. Solid samples are ground with care to achieve reproducible and reasonably uniform granulation for calibration and analysis measurements. The overall scattering characteristics of the sample which shift the reflectance baseline and control the depth of sample penetration and opportunity for absorption become a part of the method and the empirical analytical equation (6,9). Solid sampling is summarized on the following table. 

The remote sounding of land covers is based on recording the properties of reflected and scattered electromagnetic radiation. Such a possibility to obtain information about land cover properties is connected here with the facts that the character of proper (thermal) radiation, and the mechanisms of scattering and reflection are closely connected with the physical and geometrical properties of the surface, inadequate knowledge of which can also lead to erroneous conclusions and, hence, is a source of controversy in the information space. 

As the reflected radiation is emitted from the sample in a random direction, diffusely reflected radiation can be separated from, potentially sensor-blinding, specular reflections. Common techniques are off-angle positioning of the sensor with respect to the position(s) of the illumination source(s) and the use of polarisation filters. Application restrictions apply to optically clear samples with little to no scattering centres, thin samples on an absorbing background and dark samples. In either of these cases, the intensity of radiation diffusely reflected off such samples is frequently insufficient for spectral analysis. While dark objectives remain a problem, thin and/or transparent samples can be measured in transmission or in transflectance. 

For a diffuse sphere, each surface element that intercepts incident radiation will reflect the energy into the entire 2ir solid angle above that element. Thus, the radiation scattered into a specified direction will arise from the entire region of the sphere that receives radiation and is also visible from this specified direction. Consequently, the phase function for a diffuse sphere can be obtained as [Siegel and Howell, 1981]... 

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