Limb emission

Lopez-Puertas, M., G. Zaragoza, M. A. Lopez-Valverde, and F. W. Taylor, Nonlocal Thermodynamic Equilibrium (LTE) Atmospheric Limb Emission at 4.6 /urn. 1. An Update of the C02 Non-LTE Radiative Transfer Model, J. Geophys. Res., 103, 8499-8513 (1998a). 

Oelhaf, H., T.V. Clarmann, H. Fischer, F. Friedl-Vallon, C. Fritzsche, A. Linden, C. Piesch, M. Seefeldner, and W. Volker, Stratospheric CIONO2 and HNO3 profiles inside the Arctic vortex from MIPAS-B limb emission spectra obtained during EASOE. Geophys Res Lett 21, 1263, 1994. 

To develop an emission inventory for an area, one must (1) list the types of sources for the area, such as cupolas, automobiles, and home fireplaces (2) determine the type of air pollutant emission from each of the listed sources, such as particulates and SO2 (3) examine the literature (9) to find valid emission factors for each of the pollutants of concern (e.g., "particulate emissions for open burning of tree limbs and brush are 10 kg per ton of residue consumed") (4) through an actual count, or by means of some estimating technique, determine the number and size of specific sources in the area (the number of steelmaking furnaces can be counted, but the number of home fireplaces will probably have to be estimated) and (5) multiply the appropriate numbers from (3) and (4) to obtain the total emissions and then sum the similar emissions to obtain the total for the area. 

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. 

Starting with the selective chopper radiometers (SCR) on Nimbus 4 and 5, the Department of Physics at the University of Oxford developed a series of instruments observing infrared emission from the atmosphere. A pressure modulated instrument flew on Nimbus 6 and the Stratospheric and Mesospheric Sounder (SAMS) flew on Nimbus 7 (Table 1). SAMS measured in limb viewing geometry the gases C02, H20, CO, N20, CR, and NO in the stratosphere and mesosphere. An improved version of ISAMS flew aboard the UARS and added channels for N02, N205, HN03, 03, and H20 (e.g. Barnet et al., 1992) (Table 1). 

MPAS (Michelson Interferometer for Passive Atmospheric Sounding) is an ESA developed instrument to be operated on board ENVISAT-1 satellite. It will perform limb sounding observations of the atmospheric emission spectrum in the middle infrared region, from which concentration profiles of atmospheric constituents will be derived on a global scale over a period of several years. Since atmospheric emission... 

In emission spectrography35 the sample is dissolved in a suitable solvent, together with a known weight of zinc chloride. The sample is placed in a U-shaped fulgurator, one limb of which consists of a hollow graphite electrode. The test solution slowly passes to the top of this electrode and forms a film during a spark discharge between the end and a copper counter electrode. The lines of silicon (634.701 nm) and zinc (636.235 nm) are measured. 

Figure Bl.4.1. Top schematic illustration of the observing geometry used for limb sounding of the Earth s atmosphere. Bottom illustrative stratospheric OH emission spectra acquired by the SAO FIRS-2 far-infiared balloon-borne FTS in autumn 1989. The spectra are from a range of tangent heights h = tangent height in the drawing), increasing toward the bottom, where the data are represented by solid curves nonlinear least-square fits to the measurements, based on a combination of laboratory data, the physical structure of the stratosphere and a detailed radiative transfer calculation, are included as dashed curves. The OH lines are Fj 7/2 ...

The emission of forbidden lines in the solar chromosphere and corona has been studied by DE BDER et al (1972), which predicts the wavelength and intensities of these lines when the transition region between the chromosphere and the corona is seen edgewise above the solar limb. Intensities comparable to the continuum with linewidth of the order of AX/A v. 10"5 are... 

Fig. 6.4.4 Top panel / (57.2°), the average of 29 spectra near Titan s daytime east limb (average emission angle is 57.2°). Bottom panel spectral limb function A/// = [7 (57.2°) - 7 (7.3°)]// (52.7°), where 7 (7.3°) is the average of 10 spectra near the center of the disk with an average emission angle of 7.3° (after Samuelson et al 1981).

---