Infrared radiance

Infrared radiance is the amount of infrared energy primarily emitted by the quartz envelope of the UV source. This energy is collected and focused with the UV energy on the surface of the substrate to the extent depending on the IR reflectivity and efficiency of the reflector. Infrared radiafion can be expressed in exposure or irradiance units, but most commonly, the surface temperature it generates is of primary interest. The heat it produces may be a benefit or a nuisance. ... 

Hertzberg et al, "The Spectral Growth of Expanding Flames the Infrared Radiance of Methane—Air Ignitions and Coal—Dust—Air , BuMines-R 1-7779 (1973) 45) C.F. Smith,... 

Platt C.M.R. and Austin R.T. (2002). Remotely controlled, continuous observations of infrared radiance with the CSIRO/ARM Mark II radiometer of the SGP CART site. Proceedings of the 12th Atmospheric Radiation Measurement (ARM) Science Team Meeting (St. Petersburg, Florida, April 8-12, 2002), pp. 1-10. 

Pyrotechnical composition which generates smoke that is opaque to infrared radiance and smoke ammunition as obtained. US Patent 4,724,018, France. 

We have already seen that the presence of chemical pollutants causes a characteristic drop in infrared radiance temperatures, and a steep increase in the microwaves. 

The Advanced-Very-High-Resolution Radiometer (AVHRR) carried on board the NOAA-7 satellite has been collecting radiance data from the earth s surface since 1978. The polar-orbiting satellite records global data on a neardaily basis. The 4-kilometer data have been remapped by NO A A into monthly composites. The data are collected in 2 bands-one visible (VIS), the other near infrared (NIR). The Normalized Difference Vegetation Index, or NDVI, defined... 

Radiance - [INFRARED TECHNOLOGY AND RAMAN SPECTROSCOPY - INFRARED TECHNOLOGY] (Vol 14)... 

Both absorption and emission experiments have been made using a number of different instruments. The Limb Radiance Inversion Radiometer (LRIR) and Limb Infrared Monitor of the Stratosphere (LIMS) are both infrared radiometers which were flown aboard Nimbus 6 and 7, respectively, and recorded data in 1978 and 1979 (Gille et al., 1980 Gille and Russell, 1984). The six channels of LIMS observed emission by C02, HN03,03, H20 and N02 from 15-65 km. 

Thomas, RJ., C.A. Barth, D.W. Rusch and R.W. Sanders (1984) Solar mesospheric near-infrared spectrometer measurements of 1.27 mm radiances and inference for mesospheric ozone. Journal of Geophysical Research 89 9569-9580. 

Results of a comprehensive study of the absolute spectral radiance of the infrared emissions from methane—air expins have been reported (Ref 44). The spectral growth of these expanding flames was recorded with a time resolution of one msec in the spectral range 1.7— 5.0 microns. Time resolved spectra were obtained as a function of stoichiometry, nitrogen dilution and Halon dilution. Similar data are also available for coal dust-air explns. Additional applications of rapid scan IR spectroscopy are discussed in Ref 50. In this work, flare spectra (Mk45, LUU-2B and LUU-2B/B) in the 1.7-4.7 and 9—14 micron regions were studied. The Mk-45 and LUU-2B/B showed similar spectral character with Na and C02 emissions superimposed on a gray body continuum, while LUU-2B flares demonstrated variable emittance properties... 

For maximum sensitivity, the wavelength of the infrared pyrometer should also be selected based on where the spectral radiancy changes most rapidly. For example, in the temperature range depicted in Figure 8.3, a frequency of 1.5 x 10u Hz (2 /im) will permit more precise temperature measurement than a frequency of 0.4 x 1014 Hz (7.5 /im). 

Fig. 15. Spectral response of thermopile pyranometer measuring total solar radiation is shown with thick black line. Spectral radiance (brightness) of the sky dome (blue line). The cut-off at 3000 nm means the radiometer will not respond to the infrared sky radiation that peaks at 7000...

Fig. 3.4-3 shows the infrared emission spectrum (the spectral radiance) of a sample of butadiene gas alp = 107 mbar in a cuvette v, th a thickness of 10 cm at 800 K, compared to the emi.ssion spectrum of a black body at the same temperature. It is interesting to note that - as theory predicts - the percentage emission of butadiene compared to that of a black body almost equals the percentage absorption of the same gas at room temperature as recorded with an ordinary spectrometer. 

A typical 500 W tungsten lamp operates at 3000 K with an emissivity of 0.4. If the spectral radiance is plotted against wavelength, the spectral radiance will have a maximum at approximately 1000 nm and swiftly drops at approximately 300 and 5000 nm, so that the tungsten lamp is most useful in the visible and near-infrared range. 

The method presented here is based off previous research into the use of physics-based target signatures in a scheme where detection is performed in the native image radiance space. Healey Slater (1999) and Thai Healy (2002) first presented the method as a way to overcome deficiencies in atmospheric compensation of visible / near infrared / shortwave infrared (Vis / NIR / SWIR) hyperspectral imagery. In this case, variability in the at-sensor target signature manifestations is modeled through variability in properties... 

By measuring the spectral distribution of the upwelling infrared radiation emitted by the Earth and its atmosphere, spaceborne sensors can provide information on the vertical temperature profile and on the atmospheric abundance of radiatively active trace gases. When local thermodynamic equilibrium conditions apply, the radiance received by a detector with spectral response function y> over frequency interval Av and viewing vertically downwards is given by (see Eq. 4.69a)... 

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