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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 307 records · Page 17
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NASA NTRS1979

Middle atmosphere processes revealed by satellite observations

The present paper deals with satellite measurements carried out over the past decade, which include radiance measurements (closely associated with temperatures in the lower stratosphere), temperature measurements in the mesopause, and ozone distributions. Some information obtained from satellite data on chemical, dynamical, energy-balance, and transport processes is reviewed, and data suitable for testing dynamical and photochemical theories are noted.

Gille, J. C.↗
NASA NTRS1979

Evidence for vertical motions in the equatorial middle atmosphere

The Diurnal Experiment, which took place in March 1974, offers a unique data set for use in studying vertical velocities in the equatorial stratosphere and mesosphere. Application of the standard thermodynamic vertical velocity equation along with a generalized thermal wind relation reveals magnitudes of vertical velocities ranging from 1-2 cm/s in the lower stratosphere to 10-15 cm/s in the lower mesosphere. Diurnal and semidiurnal tidal modes are quite apparent and, in agreement with tidal theory, the amplitudes of the oscillations increase with height. Inspection of time cross sections and use of Fourier analysis indicates vertical wavelengths on the order of 8-16 km. These results suggest that modification of temperature and wind profiles in the stratosphere and lower mesosphere on an hourly basis can be quite significant. The analysis also suggests the presence of unresolved vertical winds on both longer and shorter time scales than the principal tidal components.

Weisman, M. L.↗
NASA NTRS1980

Trace constituents in the middle atmosphere by high resolution UV spectroscopy

An array of 5 autonomous spectrometers, the imaging spectrometric observatory covers a broad wavelength range (approximately 200 to 12,000 A), has a resolution selectable down to approximately 0.5 A, and a dynamic range of approximately 10 to the 7th power and is designed to select experiment measurement sequences by software control. Because current models of thermospheric ionic processes produce too much N2(+) ionization, the N2(+) reaction with O and the chemistry of metastable (N(+) ions and of O2(+) ions are objects of study on Spacelab 1.

Torr, D. G.↗
NASA NTRS1981

Middle atmosphere response to measured relativistic electrons

During two independent rocket programs, Aurorozone 1 and 2 at Poker Flat Research Range, Alaska in September 1976 and March 1978 respectively, frequent penetration and absorption of relativistic electrons were observed between 40-70 km altitude. This relativistic electron source was compared with bremsstrahlung X-ray energy deposition in the same altitude domain. Correlated atmospheric electrical response was simultaneously observed. Ozone was also measured following each event to determine its departure from quiet nighttime values. Preliminary results for Aurorozone 1 show that the relativistic electrons observed on September 23, 1976 dominated X-ray bremmstrahlung as an energy source to an atmospheric depth of 55 km. Above this height, the deposition ratio rapidly grew to a value greater than 100, clearly demonstrating the dominant role of relativistic electrons as an important energy source for this lower mesospheric domain.

Barcus, J. R.↗
NASA NTRS1981

Middle atmosphere project: A radiative heating and cooling algorithm for a numerical model of the large scale stratospheric circulation

A Curtis matrix is used to compute cooling by the 15 micron and 10 micron bands of carbon dioxide. Escape of radiation to space and exchange the lower boundary are used for the 9.6 micron band of ozone. Voigt line shape, vibrational relaxation, line overlap, and the temperature dependence of line strength distributions and transmission functions are incorporated into the Curtis matrices. The distributions of the atmospheric constituents included in the algorithm, and the method used to compute the Curtis matrices are discussed as well as cooling or heating by the 9.6 micron band of ozone. The FORTRAN programs and subroutines that were developed are described and listed.

Wehrbein, W. M.↗
NASA NTRS1981

A further study of the annual cycle of the zonal mean circulation in the middle atmosphere

The influence on the stratospheric mean circulation of planetary wavenumber 2 disturbances excited by steady forcing at the 100 mb level is investigated using a global semi-spectral primitive equation model. There exists a critical forcing amplitude below which the waves have little effect on the mean flow, while above which the waves produce subseasonal time scale vacillations in the winter hemisphere, including both major and minor warmings. Wave transience induced by the evolving mean flow distribution is responsible for generating the vacillations, while thermal damping serves to reduce the wave-driven changes in the mean flow.

Holton, J. R.↗
NASA NTRS1980

Environmental effects of SPS: The middle atmosphere

The heavy lift launch vehicle associated with the solar power satellite (SPS) would deposit in the upper atmosphere exhaust and reentry products which could modify the composition of the stratosphere, mesosphere, and lower ionosphere. In order to assess such effects, atmospheric model simulations were performed, especially considering a geographic zone centered at the launch and reentry latitudes.

Whitten, R. C.↗
NASA NTRS1982

The global distribution of water vapor in the middle atmosphere of Venus

Near-IR measurements are presented of the mean vertical and horizontal distribution of water vapor in the Venus clouds as measured by the Pioneer Venus Orbiter IR radiometer, and comparisons are made with previous data. Six thermal channels were used to generate several hundred thousand readings for determination of the mean mixing ratio. Averaging was performed as a function of the solar zenith angle, with profiles retrieved with a relaxation method applied to radiance data at 45 microns. Consideration was given to mean cloud models and temperature profiles obtained from the five temperature sounding channels scanning from 11.5-15 microns. Laboratory tests were effected to validate the transmission functions. The results included a maximum column abundances above the cloud optical depth in the early afternoon in the equatorial regions. Mixing ratio enhancement was highest on the dayside and at high altitudes, with a mean ratio of 0.0001 at a 40% uncertainty level. Day-to-day fluctuations in the pressure level at 11.5 microns was larger than 10%, far below the factors of 2-3 determined by other investigators.

Schofield, J. T.↗
NASA NTRS1983

Eclipse-related measurements of middle-atmosphere electrical parameters

Measurements of electrical conductivity and its constituent parameters, charge density and ion mobility, are presented for the solar eclipse rocket campaign conducted at Red Lake, Ontario, Canada. Three parachute-borne probes (two Gerdien condensers and a blunt probe) were flown during the eclipse which occurred on 26 February 1979. Additional payloads launched at other times provided important supplemental background measurements. The entire launch series occurred during aurorally active conditions, as indicated by the probe measurements. Specifically, positive conductivity enhancements above 45 km demonstrate the dominance of auroral ionization as a source for positive ions in the region. Such effects evidenced during the eclipse make it difficult to determine the extent to which the decrease in positive conductivity above 60 km is eclipse-related. The negative conductivity component associated with free electrons displays solar dependence both during the eclipse and for the other measurement periods. In spite of the aurorally active conditions, rapid electron loss was observed during totality, thus indicating the importance of non-ionizing solar effects on electrons in the region.

Mitchell, J. D.↗
NASA NTRS1983

Middle Atmosphere Program. Handbook for MAP, volume 9

The term Mesosphere-Stratosphere-Troposphere radar (MST) was invented to describe the use of a high power radar transmitter together with a large vertically, or near vertically, pointing antenna to study the dynamics and structure of the atmosphere from about 10 to 100 km, using the very weak coherently scattered radiation returned from small scale irregularities in refractive index. Nine topics were addressed including: meteorological and dynamic requirements for MST radar networks; interpretation of radar returns for clear air; techniques for the measurement of horizontal and vertical velocities; techniques for studying gravity waves and turbulence; capabilities and limitations of existing MST radar; design considerations for high power VHF radar transceivers; optimum radar antenna configurations; and data analysis techniques.

Bowhill, S. A.↗
NASA NTRS1983

Measurement of the horizontal velocity of wind perturbations in the middle atmosphere by spaced MF radar systems

Two remote receiving sites have been set up at a distance of approx 40 km from the main MF radar system. This allows measurement of upper atmosphere winds from 60-120 km (3 km resolution) at the corners of an approximately equilateral triangle of side approx 20 km. Some preliminary data are compared through cross correlation and cross spectral analysis in an attempt to determine the horizontal velocity of wind perturbations and/or the horizontal wavelength and phase velocity of gravity waves.

Meek, C. E.↗
NASA NTRS1982

Middle Atmosphere Program. Handbook for MAP, volume 4

Topics include winter in the Northern Hemisphere, temperature measurement, geopotential heights, wind measurement, atmospheric motions, photochemical reactions, solar spectral irradiance, trace constituents, tides, gravity waves, and turbulence. Highlights from the Map Steering Committee and a Map Open Meeting including organizational structure are also given.

Sechrist, C. F., Jr.↗
NASA NTRS1982

Soviet National Middle Atmosphere Program

Soviet national MAP program comprises seven projects: lower thermosphere (structure and dynamics); high latitude energetic sources and their effect on the structure and dynamics of the upper atmosphere under conditions of the polar night; climate of the stratosphere and mesosphere (effects of various energetic sources on its formation); winter variability in the lower ionosphere; noctilucent clouds (climatology, dynamics, nature, and genesis); wave processes and structure and dynamics of the stratosphere and mesosphere; and dynamics of the ozone layer.

Danilov, A. D.↗
NASA NTRS1982

The Middle Atmosphere Program: Winter In Northern Europe (MAP/WINE)

The goals of map/wind (winter in Northern Europe) are to better understand: (1) the interaction of planetary waves of tropospheric origin; (2) the temporal and spatial development of sudden stratospheric warmings; (3) the temporal and spatial development of mesospheric cooling events in conjunction with stratospheric warmings; (4) the vertical and horizontal transport of minor constituents; (5) the effects on the chemistry of neutral and charged species of the large temperature changes occurring during stratospheric warmings and mesospheric cooling; (6) sources of turbulent energy; (7) the temporal and spatial development of turbulent layers; and (8) the contributions of dynamical processes to the heating and cooling of the mesospheric and turbopause region.

Vonzahn, U.↗
NASA NTRS1982

Middle Atmosphere Program. Handbook for MAP, Volume 5

The variability of the stratosphere during the winter in the Northern Hemisphere is considered. Long term monthly mean 30-mbar maps are presented that include geopotential heights, temperatures, and standard deviations of 15 year averages. Latitudinal profiles of mean zonal winds and temperatures are given along with meridional time sections of derived quantities for the winters 1965/66 to 1980/81.

Sechrist, C. F., Jr.↗