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Boughner, R. E.

Publications and source records attributed to Boughner, R. E..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Impact of stratospheric aircraft emissions on ozone: A two dimensional model study

Atmospheric perturbations caused by the emission of nitrogen oxides from a projected fleet of stratospheric aircraft are studied with a two dimensional chemistry, transport model. Photochemistry of the lower stratosphere, the region where these aircraft may fly, is now known to be influenced by heterogeneous reactions involving sulfuric acid aerosols. This study examines the sensitivity of the atmospheric effects of aircraft to heterogeneous reactions. Information of background aerosols based on the SAGE 2 measurements have been used in the parameterization of the heterogeneous conversion rates. It is found that heterogeneous reactions make the lower stratospheric ozone less sensitive to perturbations in the odd nitrogen level. The calculated reduction in global ozone due to NO(x) injection from a fleet of Mach 2.4 aircraft is 1.28 percent if gas phase reactions only are considered in the model, and 0.06 percent if heterogeneous reactions are included.

Natarajan, M.↗
NASA NTRS1991

Sensitivity of calculated odd nitrogen distributions to the diabatic wind fields

This paper compares atmospheric total odd nitrogen and ozone computed with two different advective wind fields, one using climatological averages of ozone and temperature to obtain monthly averaged horizontal and vertical winds and the other using measurements from the LIMS instrument. Calculations using the former data show stronger poleward and downward motion in the winter season compared to those using the LIMS data. This leads to NO(y) mixing ratios in the lower stratosphere that are about 20 percent larger in the polar regions of both hemispheres and about 40 percent higher in the equatorial region for climatological transport fields compared to those derived from LIMS data. Consequently, the NO(y) distributions calculated with the LIMS advective field show worse agreement with the NO(y) values inferred from the LIMS measurements than similar results obtained with the climatological wind field.

Boughner, R. E.↗
NASA NTRS1986

Stratospheric photochemical studies using Nimbus 7 data. I - Ozone photochemistry. II - Development of inferred trace specie distributions

The present investigation has the objective to make use of the limb infrared monitor of the stratosphere (LIMS) data set in conducting stratospheric photochemical studies. A description of the data is provided. The data are utilized in a zero-dimensional model incorporating the relevant chemistry. The chemical reaction scheme considered is a subset of the scheme used in the Langley one-dimensional model discussed by Callis et al. (1983). Attention is given to a comparison of model results and data, a model uncertainty analysis, model response to modifications in rate data, the ozone-temperature relationship, and the diurnal variation in the upper stratospheric ozone.

Natarajan, M.↗
NASA NTRS1985

Comparison of band model calculations of upper atmospheric cooling rates for the 15-micrometer carbon dioxide band

Within the atmosphere of the earth, absorption and emission of thermal radiation by the 15-micron CO2 bands are the largest contributors to infrared cooling rates in the stratosphere. Various techniques for calculating cooling rates due to these bands have been described. These techniques can be classified into one of two categories, including 'exact' or line-by-line calculations and other methods. The latter methods are based on broad band emissivity and band absorptance formulations. The present paper has the objective to present comparisons of the considered computational approaches. It was found that the best agreement with the exact line-by-line calculations of Fels and Schwarzkopf (1981) could be obtained by making use of a new Doppler band model which is described in the appendix of the paper.

Boughner, R. E.↗
NASA NTRS1985

A study of the ozone photochemistry in the upper stratosphere using LIMS data

LIMS data at vernal equinox conditions are used to study the photochemistry of the upper stratosphere. The results indicate, and it has been recently reported, that with the use of recommended reaction rates, current models underestimate ozone mixing ratio by 20-40 percent. For ozone, good agreement with data is realized with the modification of six key reaction rates within the published limits of uncertainty. These modifications also yield better agreement with data for daytime NO2. Model results for other parameters such as the ratio HNO3/NO2, OH mixing ratio, and the temperature sensitivity of O3 are compared with data.

Natarajan, M.↗
NASA NTRS1985

LIMS data - Inferred stratospheric distribution of NOx and HOx trace constituents and the calculated odd nitrogen budget

LIMS, SAMS, SBUV and in-situ data have been used to infer species not measured but which are of photochemical interest, e.g., O(3P), O(1D), NO, N2O5, OH, HO2, ClO and HCl. (LIMS = limb infrared monitor of the stratosphere; SAMS = stratospheric and mesospheric sounder; and SBUV = solar backscattered ultraviolet instrument.) Production and loss of odd nitrogen have been calculated and estimates have been made of the odd nitrogen transport due to adiabatically driven circulation derived from LIMS data. Data used from LIMS include O3, NO2, HNO3, H2O and T. CH4 and N2O were taken from SAMS and the UV solar flux from the SBUV instrument. Species were inferred for periods in October, December, March and May. Results for December are discussed. Results indicate: (1) maximum stratospheric odd nitrogen levels of 25 ppbv; (2) evidence of odd nitrogen transport from the mesosphere appearing at 25 km in the wintertime polar latitudes; (3) the polar night build-up of high levels of N2O5 beginning after the autumnal equinox; and (4) the possibility of large downward fluxes of odd nitrogen into the troposphere during the winter at latitudes poleward of 60 degrees.

Callis, L. B.↗
NASA NTRS1984

Diurnal variations of atmospheric nitric oxide - Ground-based infrared spectroscopic measurements and their interpretation with time-dependent photochemical model calculations

Total vertical column amounts of NO have been derived from infrared solar absorption spectra recorded near sunrise and sunset with the 0.01 per cm resolution Fourier transform interferometer at the national Solar Observatory on Kitt peak (elevation 2095 m, latitude 31.9 degrees N) on February 23, 1981. The results show an increase in NO concentration in the morning, late afternoon values about 40 percent higher than in the morning, and a decrease in NO concentration prior to sunset. The measured diurnal changes in the total vertical column amount are compared with values obtained from time-dependent photochemical calculations.

Rinsland, C. P.↗
NASA NTRS1984

Stratospheric NO and NO2 profiles at sunset from analysis of high-resolution balloon-borne infrared solar absorption spectra obtained at 33 deg N and calculations with a time-dependent photochemical model

Simultaneous stratospheric vertical profiles of NO and NO2 at sunset were derived from an analysis of infrared solar absorption spectra recorded from a float altitude of 33 km with an interferometer system during a balloon flight. A nonlinear least squares procedure was used to analyze the spectral data in regions of absorption by NO and NO2 lines. Normalized factors, determined from calculations of time dependent altitude profiles with a detailed photochemical model, were included in the onion peeling analysis to correct for the rapid diurnal changes in NO and NO2 concentrations with time near sunset. The CO2 profile was also derived from the analysis and is reported.

Rinsland, C. P.↗
NASA NTRS1983

On the relationship between the greenhouse effect, atmospheric photochemistry, and species distribution

The coupling that exists between infrared opacity changes and tropospheric (and to a lesser extent stratospheric) chemistry is explored in considerable detail, and the effects arising from various perturbations are examined. The studies are carried out with a fully coupled one-dimensional radiative-convective-photochemical model (RCP) that extends from the surface to 53.5 km and has the capability of calculating surface temperature changes due to both chemical and radiative perturbations. The model encompasses contemporary atmospheric chemistry and photochemistry involving the O(x), HO(x), NO(x), and Cl(x) species.

Callis, L. B.↗
NASA NTRS1981

Comets and the photochemistry of the paleoatmosphere

Ozone (O3) is a key atmospheric gas in considerations of the photochemistry/chemistry of the paleoatmosphere, chemical evolution, and the origin and evolution of life. The photochemistry/chemistry of atmospheric O3 in the paleoatmosphere is investigated using a one-dimensional photochemical model that includes the chemistry of oxygen, nitrogen, hydrogen, carbon, and chlorine gases. The role of cometary influx of H2O on the photochemistry of the paleoatmosphere is also examined. Recently, it has been suggested that the planet received a significant portion of the volatiles presently in the atmospheric/oceanic/biospheric system from cometary volatile influx. Several consequences of a cometary H2O influx on the photochemistry and structure of the paleoatmosphere are presented.

Levine, J. S.↗
NASA NTRS1981

The feasibility of using time-dependent photochemical calculations to infer radical species concentrations from solar occultation absorption measurements

In connection with fast chemical reactions, short-lived stratospheric species experience rapid concentration variations at sunset and sunrise. For solar occultation absorption measurements, these rapid concentration variations may introduce significant errors with respect to the inference of atmospheric abundances for some species due to asymmetrical concentration distributions. Most retrieval algorithms assume that concentration distributions are spherically symmetric. The effect of this assumption on the accuracy of inferred concentrations has been studied by Kerr et al. (1977). The present investigation considers the feasibility of using a time-dependent one-dimensional photochemical model to provide detailed information about the asymmetrical distribution for use in the retrieval procedure. As shown by Boughner et al. (1980), diurnal effects can be represented by an inhomogeneity factor. It is found that the NO retrieval improves considerably with the inclusion of a correction factor containing the asymmetrical variations.

Larsen, J. C.↗
NASA NTRS1980

Ozone, ultraviolet flux and temperature of the paleoatmosphere

The development of surface and atmospheric levels of paleoatmospheric ozone is calculated by means of a detailed photochemical model and used to determine the levels of ultraviolet flux to the surface and the surface and atmospheric temperatures of the primitive earth. The model takes into account the chemistry of oxygen, nitrogen and hydrogen species and the effects of vertical transport in an atmosphere originally composed of as much N2, H2O and CO2 as the present atmosphere to which O2 is added to calculate the vertical profiles of O3 and nitrogen oxides as a function of O2 content. Calculations show that as oxygen content increases from 0.0001 to 1 times its present value, the height of the ozone peak moves from 5 to 25 km, and that maximum ozone densities are achieved for an O2 level of 0.1 times the present. Calculations of solar UV absorption by atmospheric species indicate the presence of a UV window between 200 and 220 nm that closed only when O2 reached 0.01 times its present level. Finally, calculations made using a radiative-convective model reveal that O3 levels corresponding to an O2 level of 0.1 times the present result in a globally averaged surface temperature increase of about 4.5 K for the present solar constant.

Levine, J. S.↗
NASA NTRS1980

A simplified method for the calculation of diurnally averaged photodissociation rates

Expressions are given for the calculation of the diurnally averaged transmission of solar flux from a series summation involving relatively few terms and readily available mathematical functions. It is shown that these expressions can be scaled to remove much of the dependence on latitude and solar declination so that at large optical depth, they become asymptotic to a function which depends only on the optical depth at noon and displays an inverse-square-root variation. From this variation, a simple analytic form containing one adjustable parameter is proposed. The functional dependence of this parameter on latitude and solar declination is determined by numerical fitting procedures. The accuracy of the analytic approximation is better than 4.5% for all altitudes, latitudes and seasons of the year.

Boughner, R. E.↗
NASA NTRS1979

The effect of paleoatmospheric ozone on surface temperature

Photochemical and radiative-convective calculations are performed to evaluate the influence of ozone in determining the surface temperature of the paleoatmosphere prior to the buildup of molecular oxygen to its present atmospheric level. Possible effects of atmospheric dynamics on the photochemistry and thermal structure of the paleoatmosphere are neglected, and the present atmospheric values are assumed for the tropospheric water-vapor relative-humidity distribution and lapse rate as well as for the fractional cloud amount and cloud reflectivity. It is found that the radiative effects (at IR and solar wavelengths) of ozone for a molecular oxygen level of one-tenth the present atmospheric level resulted in a globally averaged surface-temperature increase of about 4.5 K for the present solar constant. Implications of the results for paleoclimate are briefly considered.

Levine, J. S.↗
NASA NTRS1979

A coupled radiative-convective-photochemical model of the stratosphere

A one-dimensional atmospheric model is described. The neutral photochemical processes of the troposphere and stratosphere are presented by a reaction set of 87 kinetic processes and 28 photolytic reactions, with vertical transport being taken into account by an eddy diffusion parameter. The vertical temperature profiles are coupled with the chemical calculations by means of a radiative-convective code. The model has the capability of including effects of multiple scattering and diurnal variations in species concentrations. The numerical solution methodology is described in detail, and current input data are given along with results obtained in a sample calculation.

Boughner, R. E.↗