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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Temperature, N2, and N density profiles of Triton's atmosphere - Observations and model

Improved analysis of the Voyager Ultraviolet Spectrometer observations of the solar occultation by Triton yields the isothermal temperature and N2 number densities in the altitude range 475-675 km. The signature of atomic nitrogen in the occultation spectra is identified, its density profile is derived, and an experimental value of the escape rate of N atoms is given. The one-dimensional thermal conductivity equation for a spherical atmosphere is solved, taking into account CO heating and cooling and heating by precipitating electrons, solar radiation, and chemical effects. Finally, profiles of number densities of N, H2, and H are calculated.

Krasnopolsky, V. A.↗
NASA NTRS1984

Observing atmospheric water in storms with the Nimbus 7 scanning multichannel microwave radiometer

Employing data on integrated atmospheric water vapor, total cloud liquid water and rain rate obtainable from the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR), we study the frontal structure of several mid-latitude cyclones over the North Pacific Ocean as they approach the West Coast of North America in the winter of 1979. The fronts, analyzed with all available independent data, are consistently located at the leading edge of the strongest gradient in integrated water vapor. The cloud liquid water content, which unfortunately has received very little in situ verification, has patterns which are consistent with the structure seen in visible and infrared imagery. The rain distribution is also a good indicator of frontal location and rain amounts are generally within a factor of two of what is observed with rain gauges on the coast. Furthermore, the onset of rain on the coast can often be accurately forecast by simple advection of the SMMR observed rain areas.

Katsaros, K. B.↗
NASA NTRS1978

Jupiter's atmosphere - Observations and interpretation of the microwave spectrum near 1.25-cm wavelength

Measurements of Jupiter's disk-temperature spectrum in the 20- to 24-GHz (1.5 cm less than lambda less than 1.25 cm) region are reported. These data are combined with previously published data to produce a uniformly calibrated thermal spectrum of Jupiter in the wavelength interval 0.85 to 2.1 cm. Model studies are carried out to determine optimum pressure-temperature profiles for an assumed radiative-convective temperature structure. It is found that the temperature at the 1-bar total effective pressure level is between 140 and 165 K, with a most probable value of 153 K, provided that NH3 is uniformly saturated in the clouds on a global scale. We show that the temperature profile for the microwave model is approximately 20 K cooler than the profiles derived from infrared data. An explanation of this discrepancy is discussed in terms of a model which invokes different NH3 distributions in the belts and zones.

Klein, M. J.↗
NASA NTRS1987

Nitrous oxide in the tropical middle atmosphere, observed by ground-based mm-wave spectrometry

Measurements of stratospheric N2O were made from Mauna Kea in Hawaii in June 1983, and in May and June 1986, by observing thermal emission of the molecule in a rotational transition at about 1 mm wavelength. Analyses of the data yield altitude profiles in the middle and upper stratosphere. Useful measurements of N2O may be made in one to two hours. The N2O profiles agree reasonably well with model predictions and with published satellite data, though significantly more N2O is reported near the stratopause than shown by the satellite measurement, and significantly more N2O in the middle stratosphere than in one of the models. The discrepancy between these data and the satellite measurement may be due in part to variations induced by the solar cycle.

Connor, Brian J.↗
NASA NTRS1989

Wind and waves in the middle atmosphere observed with the MU radar

The VHF band MU radar at Shigaraki, Japan, has been in full operation successfully since April 1985. Dynamical features found primarily in the data obtained by the radar during a one year period from December 1985 to November 1986 are examined. These include: basic wind observations, quasi-monochromatic gravity waves generated by the jet stream or through a geostrophic adjustment process, seasonal variation of the mesoscale wind variability, the momentum flux due to gravity wave motions, and saturated gravity wave spectrum. A short discussion is added to the relationship between turbulent layers and ambient wind field in the mesosphere.

Fukao, S.↗
NASA NTRS1993

Line widths of (N-14)H3 and (N-15)H3 applicable to planetary atmospheric observations

The collision-broadened half-widths of sP(1,0), sP(3,2), sP(4,1), sP(4,2), and sP(4,3) in the v2 sup s-fundamental bands of (N-14)H3 and (N-15)H3 have been measured at 198, 245, and 295 K employing the Doppler-limited spectral resolution of a tunable diode laser spectrometer. The temperature dependence of the collision-broadened half-widths of these lines broadened by H2 and N2 has been determined. In addition, we have also measured the air-broadened line widths of all of these lines at 295 K and the half-width of the sP(3,2) line of (N-15)H3 broadened by (N-14)H3 at 198, 245, and 295 K.

Varanasi, Prasad↗
NASA NTRS1999

Mars Global Surveyor Thermal Emission Spectrometer (TES) Observations: Atmospheric Temperatures During Aerobraking and Science Phasing

Between September 1997, when the Mars Global Surveyor spacecraft arrived at Mars, and September 1998 when the final aerobraking phase of the mission began, the Thermal Emission Spectrometer (TES) has acquired an extensive data set spanning approximately half of a Martian year. Nadir-viewing spectral measurements from this data set within the 15-micrometers CO2 absorption band are inverted to obtain atmospheric temperature profiles from the surface up to about the 0.1 mbar level. The computational procedure used to retrieve the temperatures is presented. Mean meridional cross sections of thermal structure are calculated for periods of time near northern hemisphere fall equinox, winter solstice, and spring equinox, as well as for a time interval immediately following the onset of the Noachis Terra dust storm. Gradient thermal wind cross sections are calculated from the thermal structure. Regions of possible wave activity are identified using cross sections of rms temperature deviations from the mean. Results from both near-equinox periods show some hemispheric asymmetry with peak eastward thermal winds in the north about twice the magnitude of those in the south. The results near solstice show an intense circumpolar vortex at high northern latitudes and waves associated with the vortex jet core. Warming of the atmosphere aloft at mid-northern latitudes suggests the presence of a strong cross-equatorial Hadley circulation. Although the Noachis dust storm did not become global in scale, strong perturbations to the atmospheric structure are found, including an enhanced temperature maximum aloft at high northern latitudes resulting from intensification of the Hadley circulation. TES results for the various seasonal conditions are compared with published results from Mars general circulation models, and generally good qualitative agreement is found.

Conrath, Barney J.↗