Engineering topics
Publications and source records attributed to Murcray, D. G..
Solar irradiance measurements made from a balloon on January 27, 1978 and February 10, 1980 show a change of 0.4% over similar measurements made in 1968. This change is greater than the uncertainty of the measurement and is felt to be the result of a change in the solar constant.
The photochemistry of the stratospheric ozone layer was studied as the result of predictions that trace amounts of pollutants can significantly affect the layer. One of the key species in the determination of the effects of these pollutants is the OH radical. A balloon flight was made to determine whether data on atmospheric OH could be obtained from lower resolution solar spectra obtained from high altitude during sunset.
High-resolution (0.02/cm) infrared solar spectra obtained with a balloon-borne interferometer reveal new solar absorption features, which appear as regularly spaced quartets, in the 825-960/cm region. The lines are interpreted as high N-double-prime (25-33) pure rotation lines of solar OH. An effective amount of approximately 8 x 10 to the 15th molecules/sq cm of OH is estimated from the spectra.
Long path atmospheric infrared spectra at 0.02 per cm resolution, as obtained by the University of Denver from balloon experiments will be presented. The spectra will be analysed in terms of quantifying atmospheric trace constituents. Identification of new atmospheric spectral lines will be demonstrated. Spectral regions which require further experimental and theoretical work for more accurate modeling of atmospheric transmission will be discussed.
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Ballon-borne infrared solar spectra at about 0.02/cm resolution show a number of atmospheric NO lines isolated from other atmospheric and solar lines in the 1830-1930/cm region. Typical spectra are presented and NO total column values are derived.
Nonlinear least squares spectral curve fitting has been used to derive vertical mixing ratio profiles for NO2 and H2O above 16 km from high resolution (0.2/cm) solar spectra collected during sunset with a balloon borne interferometer. The NO2 profile shows a sharp peak of 8 ppbv at 32 km falling rapidly to less than 0.5 ppbv at 17 km. The H2O profile shows a broad peak of 6.5 ppmv at 30 km falling to less than 4 ppmv at 17 km.
Over 4500 absorption lines have been marked on the spectra and the corresponding line positions tabulated. The associated absorbing telluric or solar species for more than 90% of these lines have been identified and only a fraction of the unidentified lines have peak absorptions greater than a few percent. The high resolution and the low Sun spectra greatly enhance the sensitivity limits for identification of trace constituents.
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Infrared heterodyne techniques were considered primarily for detecting molecules predicted to be present but not yet detected in the upper atmosphere.
The use of solar occultation techniques as a means of obtaining data on the photochemistry of the ozone layer was investigated. A spectrometer equipped with a photomultiplier detector and associated electronics necessary to amplify the output of the detector up to a level suitable for on-board recording and also for telemetering to the ground, was packaged with a solar telescope and flown by balloon in order to obtain solar spectra in the region between 3080 A and 3100 A with a resolution of close to 0.05 A. Data reduction techniques required to remove solar OH lines from atmospheric OH line spectra are described as well as the instrument package.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Balloon-borne infrared solar spectra in the 1292/cm region, at 0.02/cm resolution, obtained during sunset, are used to derive a mixing ratio altitude profile of ClONO2. Portions of the spectra covering the 1292/cm region are shown together with a laboratory spectrum of ClONO2 and HNO3 taken with a flight interferometer. The agreement of the atmospheric absorption feature in shape and position with the ClONO2 spectrum, along with the fact that the feature is not due to other known atmospheric compounds, results in the identification of the atmospheric absorption as being due to ClONO2.
Infrared solar spectra in the 850 to 1350/cm region, at 0.02/cm resolution, were obtained during a balloon flight made on 27 October 1978 from Alamogordo, New Mexico. Analysis of the 1275-1290/cm region indicates that the atmospheric absorption lines of CH4, N2O, H2O, HNO3 and CO2 near 1283/cm are super-imposed on a broader absorption feature which we interpret as due to the V3 band of CF4. Fine structure of CF4 is also identified. Preliminary estimates from the sunset spectra show approximately 75 pptv CF4 near 25 km.
The Denver University Infrared Spectrometer (DUIRS) is a liquid-helium-cooled emission radiometer designed to study minor atmospheric constituents. DUIRS flew on 12 data flights during the 1977 Intertropical Convergence Zone experiment. No data were obtained on the flight from Wallops Island to Panama because of a power failure or on the return flight to Wallops Island because of a cryogen line freeze-up. The data coverage on the nine vertical profile flights that were flown before the freeze-up are shown. Typical spectra and variations as a function of U-2 (research aircraft) altitude are also shown. Radio metric data and rawinsonde temperature data were used to perform band model calculations to obtain molecular number densities in the column above the aircraft at each altitude.