Engineering topics

Pyle, John A.

Publications and source records attributed to Pyle, John A..

4 records

NASA NTRS1991

Ozone depletion and chlorine loading potentials

The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

Pyle, John A.↗

NASA NTRS1991

Predicted rocket and shuttle effects on stratospheric ozone

The major chemical effluents of either solid- or liquid-fueled rockets that can potentially perturb stratospheric ozone include chlorine compounds (HCl), nitrogen compounds (NO(x)), and hydrogen compounds (H2 and H2O). Radicals (Cl, ClO, H, OH, HO2, NO, and NO2) formed directly or indirectly from rocket exhaust can cause the catalytic destruction of ozone. Other exhaust compounds that could presumably lead to ozone destruction either by direct reaction with ozone or by providing a surface for heterogeneous processes include the particulates Al2O3, ice, and soot. These topics are discussed in terms of the possible effects of rocket exhausts on stratospheric ozone.

Harwood, Robert S.↗

NASA NTRS1990

Active nitrogen partitioning and the nighttime formation of N2O5 in the stratosphere - Simultaneous in situ measurements of NO, NO2, HNO3, O3, and N2O using the BLISS diode laser spectrometer

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Webster, Christopher R.↗

NASA NTRS1987

Odd nitrogen during the MAP/GLOBUS 1983 campaign - Theoretical considerations

The paper reviews the chemical processes involved in the formation and destruction of active nitrogen in the stratosphere and indicates that transport processes play an important role in the behavior of these species. Vertical profiles measured during the MAP/GLOBUS 1983 campaign are compared to distributions calculated by a number of one-dimensional models. An intercomparison between six of these models shows that, if some quantitative differences attributed to different model input are noticeable, the same type of behavior is predicted for NO and NO2 by all models. Although the observed concentration of species belonging to the odd nitrogen family should be highly variable, as a result of dynamical disturbances, most data obtained during the campaign appear to be consistent with the chemical scheme currently used in photochemical models.

Brasseur, Guy↗