Satellite instrumentation

Measurements either from the ground or from satellites have been a major contribution to this effort, and satellite instruments such as LIMS (Limb Infrared Monitor of the Stratosphere) on the Nimbus 7 satellite (I) in 1979 and ATMOS (Atmospheric Trace Molecular Spectroscopy instrument), a Fourier transform infrared spectrometer aboard Spacelab 3 (2) in 1987, have produced valuable data sets that still challenge our models. But these remote techniques are not always adequate for resolving photochemistry on the small scale, particularly in the lower stratosphere. In some cases, the altitude resolution provided by remote techniques has been insufficient to provide unambiguous concentrations of trace gas species at specific altitudes. Insufficient altitude resolution is a handicap particularly for those trace species with large gradients in either altitude or latitude. Often only the most abundant species can be measured. Many of the reactive trace gases, the key species in most chemical transformations, have small abundances that are difficult to detect accurately from remote platforms. 

An alternative strategy is to make a large number of in situ measurements and examine how the balance between production and loss changes for different conditions. Particularly important are variations with altitude, because the relative importance of the various chemical families to ozone loss changes between 20 and 45 km. Seasonal and latitudinal effects are important for testing both the production and the transport of ozone. At present, the main source of data for these variations comes from satellite instruments, although in situ instruments have been used for several altitudinal studies, primarily by balloon-borne instruments, and some limited seasonal and latitudinal studies. 

Satellite instrumentation orbiting the earth view the stratosphere in limb and nadir viewing geometries. In addition both solar, lunar and stellar occulation have also been exploited very successfully. 

Altitude-resolved measurements of ozone and other constituents are necessary for improving our knowledge of physical and chemical processes in the stratosphere. Limbviewing satellite instruments can measure density profiles of stratospheric constituents at a good altitude resolution (1-3 km). In addition, satellite-based measurements have a global geographical coverage. 

Ultraviolet) instrument and from SAGE II (Stratospheric Aerosol and Gas Experiment II), together with supporting data from ozonesondes and satellite instruments such as SME (Solar Mesosphere Explorer) and TOMS (Total Ozone Mapping Spectrometer). The model interpolates monthly ozone values to its timestep and this time-varying ozone repeats every simulation year. The model currently does not allow the ozone to become interactive, neither does it represent any change in ozone due to chemical processes, although work is underway to incorporate these features. 

Global climatologies of stratospheric aerosols have been produced from observations by satellite instruments. Hitchman et al. (1994), for example, have provided meridional distributions of measured extinction ratios based on 9 years of data from the Stratospheric Aerosol and Gas Experiment (SAGE I and II) and the Stratospheric Aerosol... 

Operational satellite instruments based on the principles of geometrical optics include SIGMA, OSSE and BATSE (Paul et al. 1991, Johnson et al. 1993, and Fishman et al. 1989). While the detection plane of all three of them is based on scintillators AEfE 10), different aperture systems are used. Whereas OSSE and BATSE perform temporal modulation with collimators and the earth (an anticollimator ) respectively, SIGMA is a multiplexing device using spatial modulation with a coded mask. 

Ultimately however, the concept should be put to use in space where longer exposures and steady pointing would result in outstanding sensitivities. Yet, as a satellite instrument, a monochromatic lens would clearly be a handicap since its scientific objectives are too exclusive - already e.g. the possible annihilation line of most extragalactic sources (AGN s, quasars) would be inaccessible because of cosmological redshift. 

Figure 4.27 The phosphatidylcholine (PC) region of the NMR spectrum of (a) bovine heart phospholipids (b) bovine lung surfactant. PC phosphatidylcholine. = signals caused by C satellites. Instrument details are given in text, Section 4.10.

Total Ozone Mapping Spectrometers (TOMS) measure solar irradiance and radiance backscattered by the earth s atmosphere at six wavelengths extending from approximately 310 to 380 nm. TOMS measurements can be used to estimate the tropospheric ozone amount by the calculation of the difference of total ozone minus stratospheric ozone amount measmed by another satellite instrument (SAGE Stratospheric Aerosol and Gas Experiment), in particular when stratospheric ozone variations are small, usually over the tropics. However, the residual tropospheric ozone calculation has some limitation in accuracy because the tropospheric ozone amount is calculated as a small difference of two large numbers (total and stratospheric ozone). Measurements of the TOMS instra-ment on Nimbus 7 satellite have been used to estimate tropical tropospheric ozone trends from 1978 to 1992. 

Kidder, Stanley Q., and Thomas H. Yonder Haar. Satellite Meteorology. 1995. Reprint. San Diego Academic Press, 2008. Covers ways in which satellite instruments can monitor meteorological phenomena at several levels of the atmosphere. 

Satellite Instrument in orbit around the Earth that is used to amplify, receive, or transmit electromagnetic signals over a wide geographic area. 

Calibration of aero-transported VIS/NIRS and hyperspecttal satellite instruments with data obtained at field levels. 

Dufour, G, S. Szopa, M.P. Barkley, C.D. Boone, A. Perrin, PI. Palmer, and P.F. Bernath (2009), Global upper-tropospheric formaldehyde seasonal cycles observed by the ACE-FTS satellite instrument, Atmos. Chem. Phys. Disc., 9, 1051-1095... 

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