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Grose, W. L.

Publications and source records attributed to Grose, W. L..

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Numerical experiments with a general circulation model concerning the distribution of ozone in the stratosphere

The distribution of ozone below 60 km altitude has been simulated in two experiments employing a nine-layer quasi-geostrophic spectral model and linear parameterization of ozone photochemistry, the first of which included thermal and orographic forcing of the planetary scale waves, while the second omitted it. The first experiment exhibited a high latitude winter ozone buildup which was due to a Brewer-Dodson circulation forced by large amplitude (planetary scale) waves in the winter lower stratosphere. Photochemistry was also found to be important down to lower altitudes (20 km) in the summer stratosphere than had previously been supposed.

Kurzeja, R. J.↗
NASA NTRS1984

Recent advances in understanding stratospheric dynamics and transport processes - Application of satellite data to their interpretation

The present paper discusses the use of the transformed Eulerian (or 'residual') mean-flow formulation, the Eliassen-Palm flux, and Ertel's potential vorticity to provide an increased understanding of wave, mean-flow interactions, and constituent transport processes in the stratosphere. Temperature and ozone data retrieved from radiance profiles obtained by the LIMS instrument on the Nimbus 7 satellite are utilized in conjunction with these theoretical concepts for the interpretation of phenomena that occurred during the major and minor warmings of January-February 1979. The results illustrate the insight provided by these concepts and demonstrate that useful diagnostic quantities can be derived from global satellite temperature fields.

Grose, W. L.↗
NASA NTRS1981

Numerical simulation of a sudden stratospheric warming with a three-dimensional, spectral, quasi-geostrophic model

An analysis of a sudden stratospheric warming which developed spontaneously during a winter simulation with a three-dimensional quasi-geostrophic model is described. Changes in the circulation and thermal structure of the winter polar stratosphere that occurred during the warming are shown to be in close agreement with observed behavior: enhanced vertical flux of eddy energy into the stratosphere, rapid temperature increase in high latitudes with a reversal of the zonal mean temperature gradient between midlatitude and pole, destruction of the circumpolar cyclonic vortex, and a marked deceleration of the westerly jet and the appearance of zonal mean easterlies. Energies of the warming are also consistent with observed characteristics. Many aspects of the dynamical development of the present model simulation are shown to agree with a previous model simulation, but there are also areas of disagreement.

Grose, W. L.↗
NASA NTRS1981

Energetics of a sudden stratospheric warming simulated with a three-dimensional, spectral, quasi-geostrophic model

The energetics of a three dimensional, quasi-geostrophic simulation of a sudden stratospheric warming which developed spontaneously during an annual cycle simulation are described. Daily values of the stratospheric temperatures, zonal winds, heating rates, energies, and energy conversions are discussed and compared with those for observed warmings. It is shown that, like observed warmings, the simulated warming was preceded by an increased vertical flux of eddy kinetic energy from the troposphere and the polar heating resulted because of the strong convergence of the horizontal, eddy heat flux which was only partially balanced by adiabatic and diabatic cooling. There is a significant similarity between the energetics of the simulated and observed warmings. In addition, the warming was spontaneous and the model did not develop a major warming in each winter of the simulation. These facts suggest that this model may be useful for studying not only the warming process but also the conditions that favor its development.

Haggard, K. V.↗
NASA NTRS1981

Numerical experiments with a general circulation model concerning the stratospheric distribution of ozone

Three experiments have been performed using a three-dimensional, spectral quasi-geostrophic model in order to investigate the sensitivity of ozone transport to tropospheric orographic and thermal effects and to the zonal wind distribution. In the first experiment, the ozone distribution averaged over the last 30 days of a 60 day transport simulation was determined; in the second experiment, the transport simulation was repeated, but nonzonal orographic and thermal forcing was omitted; and in the final experiment, the simulation was conducted with the intensity and position of the stratospheric jets altered by addition of a Newtonian cooling term to the zonal-mean diabatic heating rate. Results of the three experiments are summarized by comparing the zonal-mean ozone distribution, the amplitude of eddy geopotential height, the zonal winds, and zonal-mean diabatic heating.

Kurzeja, R. J.↗
NASA NTRS1980

The coupled effects of chemistry and diffusion on the stratospheric ozone reduction

The effect of diffusive-mixing on O3-depletion is estimated using the five-step chemistry model. The coupled treatment uses an equilibrium turbulence field and retains the key features of the kinetics while keeping the chemistry simple. Results indicate that those calculations of Hilst and Donaldson (1973) employing the conservation of NO2/NO will yield erroneous results, and it is found that any significant level of turbulence will reduce the severity of the NOx catalytic cycle for O3 destruction.

Gupta, R. N.↗
NASA NTRS1979

On the influence of orography on large-scale atmospheric flow

The steady response to orography as described by shallow-water equations on the sphere is examined in an attempt to provide insight into the dynamical effects of large-scale orographic features on atmospheric motion. The model equations and the zonal flows and orography used in the study are described. The results for simple mountains and for the earth orography are given. The two-dimensional nature of the horizontal propagation on the sphere is emphasized. The results give interesting indications of the regions of influence of mountains and suggest that quantitative theories of the stationary waves must involve a full representation of the spherical domain.

Grose, W. L.↗
NASA NTRS1978

A numerical simulation of seasonal stratospheric climate. I - Zonal temperatures and winds

Two numerical experiments were designed to isolate the effects of seasonal and latitudinal variations in longwave radiative transfer processes. The first experiment aimed at computing the rate of temperature change in the stratosphere due to longwave radiative transfer by CO2, H2O and O3 from Ramanathan's (1976) radiative-convective model applied to the troposphere-stratosphere circulation. The second experiment employs the Newtonian cooling approximation in which the rate of temperature change in the stratosphere by longwave radiative transfer is set equal to the product of the Newtonian cooling coefficient 'h' and the departure of the local temperature from a reference temperature. It is shown that the latitudinal temperature distribution of the lower stratosphere is maintained by the combined effects of dynamics, O3 solar heating and the longwave radiative coupling between troposphere and stratosphere. The latitudinal gradient in the troposphere-stratosphere longwave radiative coupling is maximum during winter and spring. The radiative response time (1/h) of the middle and upper stratosphere undergoes significant latitudinal and seasonal variations, largely due to the temperature dependence of h.

Ramanathan, V.↗
NASA NTRS1977

A three-D circulation model study of the radiative-dynamic coupling within the stratosphere

The role of radiative transfer processes in the general circulation of the stratosphere was studied by comparing the thermal and dynamical structure of the stratosphere as simulated by two controlled numerical experiments performed with the aid of a spectral 3-dimensional quasi-geostrophic circulation model. In the first experiment, a detailed radiative transfer model is employed to treat the longwave radiative transfer in the stratosphere. In the second experiment, longwave radiative transfer is accounted for by employing the Newtonian cooling approximation. It is found that the exchange of longwave radiation between the troposphere and lower stratosphere has a net heating effect on the lower stratosphere. It is shown that this heating effect contributes partly to the maintenance of the warm high-latitude belt in the lower stratosphere during winter and spring seasons. The strong temperature dependence of the Newtonian cooling coefficient plays an important role in determining the zonal temperatures and has a significant influence on the transmissivity of stratosphere to propagating planetary scale waves.

Ramanathan, V.↗
NASA NTRS1975

Some aspects of the ozone-depletion problem in the stratosphere

A preliminary investigation of O3 depletion by NOx in the exhaust of an SST wake is presented. Initial calculations were made using a model employing a two-step chemistry mechanism consisting of an NOx catalytic cycle and assuming total NOx and the ratio NO/NO2 to be conserved. The results indicate O3 depletion in the wake much less severe than reported in earlier investigations which used a much larger reaction rate constant. Subsequent investigation revealed, however, that even the current O3 depletion rates appear too large. Because of the apparent deficiencies in the two-step chemical model, a model is presented with a more realistic chemical mechanism without the requirement for NO conservation. Results indicate that total NOx and initial NO/NO2 ratio play an important role in determining O3 depletion. Furthermore, only in the case of rather extreme concentrations of water vapor or unrealistically large photolysis rates is there any significant conversion of NOx to HNO3.

Gupta, R. N.↗
NASA NTRS1975

Parametric studies with an atmospheric diffusion model that assesses toxic fuel hazards due to the ground clouds generated by rocket launches

Parametric studies were made with a multilayer atmospheric diffusion model to place quantitative limits on the uncertainty of predicting ground-level toxic rocket-fuel concentrations. Exhaust distributions in the ground cloud, cloud stabilized geometry, atmospheric coefficients, the effects of exhaust plume afterburning of carbon monoxide CO, assumed surface mixing-layer division in the model, and model sensitivity to different meteorological regimes were studied. Large-scale differences in ground-level predictions are quantitatively described. Cloud alongwind growth for several meteorological conditions is shown to be in error because of incorrect application of previous diffusion theory. In addition, rocket-plume calculations indicate that almost all of the rocket-motor carbon monoxide is afterburned to carbon dioxide CO2, thus reducing toxic hazards due to CO. The afterburning is also shown to have a significant effect on cloud stabilization height and on ground-level concentrations of exhaust products.

Stewart, R. B.↗
NASA NTRS1975

Estimates of nonequilibrium radiation for Venus entry

The present investigation is an analysis of the radiation from the chemical nonequilibrium region in the shock layer about a vehicle during Venus entry. The radiation and the flow were assumed to be uncoupled. An inviscid, nonequilibrium flowfield was calculated and an effective electronic temperature was determined for the predominant radiating species. Species concentrations and electronic temperature were then input into a radiation transport code to calculate heating rates. The present results confirm earlier investigations which indicate that the radiation should be calculated using electronic temperatures for the radiating species. These temperatures are not related in a simple way to the local translational temperature. For the described mission, the nonequilibrium radiative heating rate is approximately twice the corresponding equilibrium value at peak heating.

Grose, W. L.↗
NASA NTRS1975

An analysis of communications blackout for Pioneer Venus entry probes

Estimates of the maximum duration of communications blackout are presented for a proposed Pioneer Venus mission involving a multiprobe entry targeted to individual impact sites. Calculations of the inviscid flow about the probes have been made using both finite-rate chemistry and equilibrium chemistry computer codes. Equilibrium boundary-layer calculations including ablation are also presented both with and without the presence of alkali metal contaminants from the heat shield. Methods are described for estimating maximum electron density in the inviscid wake and the recirculation region at the base of the probes. The results presented provide a conservative basis for planning for storage and subsequent telemetry of data during the entry phase of the mission.

Grose, W. L.↗
NASA NTRS1973

Combustion detector

A device has been developed for generating a rapid response signal upon the radiation-emitting combustion reaction of certain gases in order to provide a means for the detection and identification of such reaction and concurrently discriminate against spurious signals. This combustion might be the first stage of a coal mine explosion process, and thereby this device could provide a warning of the impending explosion in time to initiate quenching action. This device has the capability of distinguishing between the light emitted from a combustion reaction and the light emitted by miners' lamps, electric lamps, welding sparks or other spurious events so that the quenching mechanism is triggered only when an explosion-initiating combustion occurs.

Trimpi, R. L.↗