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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Atmospheric temperature sounding from space

The physical principles underlying thermal radiation are reviewed. The main factors complicating the interpretation of observations in the infrared are clouds, precipitation, scattered solar radiation, and various atmospheric constituents. At microwave wavelengths, the principal factors complicating propagation are precipitation and variable surface emissivity. The devices that have been used since the Nimbus-5 Microwave Spectrometer are surveyed. The rms accuracies of retrieved temperature profiles are at present approximately 1-3 K under favorable cloudless circumstances. Attention is also given to improvements expected in the 1990s.

Staelin, D. H.↗
NASA NTRS1991

The inflatable sphere - A technique for the accurate measurement of middle atmosphere temperatures

The present study illustrates the inflatable sphere's capability to produce accurate temperatures up to 85 km and higher, given that the necessary reduction initialization conditions are met. At heights below 60 km, comparison of sphere temperatures with in situ thermistor measurements obtained close in space and time shows good agreement. Comparison with OH-radical rotational temperatures also confirms excellent agreement at 86 km. It is concluded that the sphere technique is an independent and highly accurate source of temperature measurement, is unique in being the only low-cost source of in situ measurement of temperature throughout the mesosphere and lower thermosphere, and qualifies as an intrinsic method to establish the accuracy of other atmosphere measurement systems.

Schmidlin, F. J.↗
NASA NTRS1992

Intensity and linewidth measurements in the 13.7-micron fundamental bands of (C-12)2H2 and (C-12)(C-13)H2 at planetary atmospheric temperatures

The absolute intensities and collision-broadened half-widths of several lines in the P-,Q-, and R-branches of the nu5-fundamental band of (C-12)2H2 have been measured at various temperatures between 147 and 295 K employing the Doppler-limited spectral resolution (about 10 exp -4/cm) of a tunable diode laser spectrometer. The absolute intensities of R(5), R(7), R(9), and R(20) in the same fundamental belonging to (C-12)(C-13)H2 have also been measured at 294 K. The temperature dependence of the collision-broadened half-width has been determined for some of the lines broadened by planetary atmospheric gases, namely, He, Ar, H2, and N2. Four self-broadened linewidths of (C-12)2H2, as well as three H2-broadened linewidths and a self-broadened half-width of (C-12)(C-13)H2, have also been retrieved from the measurements.

Varanasi, Prasad↗
NASA NTRS2010

Temporal Variations of Titan's Middle-Atmospheric Temperatures From 2004-2009 Observed by Cassini/CIRS

We use five and one-half years of limb- and nadir-viewing temperature mapping observations by the Composite Infrared Radiometer-Spectrometer (CIRS) on the Cassini Saturn orbiter, taken between July 2004 and December 2009 (Ls from 293deg to 4deg; northern mid-winter to just after northern spring equinox), to monitor temperature changes in the upper stratosphere and lower mesosphere of Titan. The largest changes are in the northern (winter) polar stratopause, which has declined in temperature by over 20 K between 2005 and 2009. Throughout the rest of the mid to upper stratosphere and lower mesosphere, temperature changes are less than 5 K. In the southern hemisphere, temperatures in the middle stratosphere near 1 mbar increased by 1 to 2K from 2004 through early 2007, then declined by 2 to 4K throughout 2008 and 2009, with the changes, being larger at more, polar latitudes. Middle stratospheric temperatures at mid-northern latitudes show a small 1 to 2K increase, from 2005 through 2009. At north polar latitudes within the polar vortex, temperatures in the middle stratosphe=re show a approx. 4 K increase during 2007, followed by a comparable decrease in temperatures in 2008 and into early 2009. The observed temperature. changes in the north polar region are consistent with a weakening of the subsidence within the descending branch of the middle atmosphere meridional circulation.

Achterberg, Richard K.↗
NASA NTRS2011

Temporal Variations of Titan's Middle-Atmospheric Temperatures from 2004 to 2009 Observed by Cassini/CIRS

We use five and one-half years of limb- and nadir-viewing temperature mapping observations by the Composite Infrared Radiometer-Spectrometer (CIRS) on the Cassini Saturn orbiter, taken between July 2004 and December 2009 (Ls from 293 deg. to 48 deg.; northern mid-winter to just after northern spring equinox), to monitor temperature changes in the upper stratosphere and lower mesosphere of Titan. The largest changes are in the northern (winter) polar stratopause, which has declined in temperature by over 20 K between 2005 and 2009. Throughout the rest of the mid to upper stratosphere and lower mesosphere, temperature changes are less than 5 K. In the southern hemisphere, temperatures in the middle stratosphere near 1 mbar increased by 1-2 K from 2004 through early 2007, then declined by 2-4 K throughout 2008 and 2009, with the changes being larger at more polar latitudes. Middle stratospheric temperatures at mid-northern latitudes show a small 1-2 K increase from 2005 through 2009, at north polar latitudes within the polar vortex, temperatures in the middle stratosphere show an approximately 4 K increase during 2007, followed by a comparable decrease in temperatures in 2008 and into early 2009. The observed temperature changes in the north polar region are consistent with a weakening of the subsidence within the descending branch of the middle atmosphere meridional circulation.

Achterberg, Richard K.↗
NASA NTRS2010

Improved Determination of Surface and Atmospheric Temperatures Using Only Shortwave AIRS Channels: The AIRS Version 6 Retrieval Algorithm

AIRS was launched on EOS Aqua on May 4, 2002 together with ASMU-A and HSB to form a next generation polar orbiting infrared and microwave atmosphere sounding system (Pagano et al 2003). The theoretical approach used to analyze AIRS/AMSU/HSB data in the presence of clouds in the AIRS Science Team Version 3 at-launch algorithm, and that used in the Version 4 post-launch algorithm, have been published previously. Significant theoretical and practical improvements have been made in the analysis of AIRS/AMSU data since the Version 4 algorithm. Most of these have already been incorporated in the AIRS Science Team Version 5 algorithm (Susskind et al 2010), now being used operationally at the Goddard DISC. The AIRS Version 5 retrieval algorithm contains three significant improvements over Version 4. Improved physics in Version 5 allowed for use of AIRS clear column radiances (R(sub i)) in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations were used primarily in the generation of clear column radiances (R(sub i)) for all channels. This new approach allowed for the generation of accurate Quality Controlled values of R(sub i) and T(p) under more stressing cloud conditions. Secondly, Version 5 contained a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 contained for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Susskind et al 2010 shows that Version 5 AIRS Only sounding are only slightly degraded from the AIRS/AMSU soundings, even at large fractional cloud cover.

Susskind, Joel↗
NASA NTRS1979

The influence of ozone on Martian atmospheric temperature

Radiative equilibrium temperature calculations for Mars are presented, using the model of Kuhn et al. (1978). The maximum amount of ozone measured was 57 microns over the polar hood during winter. Results indicate that, although a minor constituent in the Martian atmosphere, ozone may play a significant role in controlling the rate of carbon dioxide deposition and thus the atmospheric pressure.

Kuhn, W. R.↗
NASA NTRS1972

Microwave radiometric measurements of atmospheric temperature and water from an aircraft.

A five-channel microwave spectrometer operating near the 1.35-cm wavelength water vapor and the 5-mm wavelength oxygen resonances was flown in the NASA Convair 990 aircraft at altitudes near 12 km and used to infer layer thicknesses and water vapor and liquid water abundances in the troposphere. The calibration of the spectrometer and a multiple regression method of interpretation of the data obtained from the flights are described. Possible errors from clouds and from the terrestrial surface are discussed. Values of atmospheric layer thicknesses, water vapor content, and liquid water content inferred from microwave data obtained over two frontal systems are presented. The inferred values of 1000- to 500-mb and 500- to 250-mb thicknesses agree with directly measured values to within 15 meters at the places where the direct measurements were made. This agreement is equivalent to errors of less than 1 K in mean temperature.

Rosenkranz, P. W.↗
NASA NTRS2002

Middle Atmosphere Temperature Trends from Small Rocketsondes

Stratospheric temperature trends derived from United States meteorological rocketsonde measurements obtained between the late 1960's and mid 1990's are examined at the 50-, 40-, and 25-km altitude levels. Although the trends are different at each of the launch locations there is an unequivocal downward slope of about -0.1 K to -0.3K per year at many of the launch sites. Distances between launch sites and, in some cases unequal data-record lengths, inhibit determination of trend inter-relationship among the various sites. Although the data only provide a 'snapshot' of atmospheric behavior for the specific location, a particular advantage resulting from using these particular rocketsonde observations is their consistency over time. Thus, using the same rocketsonde type over the data period, i.e., Datasonde insures a significant reduction of instrument induced anomalies in the temperature profiles. Trends at the 25-km altitude level, approximately 30 hPa, are compared with trends from radiosonde observations. Both rocketsonde and radiosonde measurements were obtained at approximately the same local times and within less than 100 km of each other. Rocketsonde temperatures from the Former Soviet Union are also used and often complement trends from US data.

Schmidlin, F. J.↗
NASA NTRS1973

The neutral-atmosphere temperature instrument.

The determination of the temperature of the neutral gas at the location of the satellite is based on measurement of the velocity distribution of the molecular nitrogen. Measurement of the thermal-velocity component in the presence of the free-stream velocity will be obtained through application of the velocity-scan technique and, independently, through use of a baffle technique. A 3-cm diameter spherical sampling chamber with a 0.5-cm diameter precisely knife-edged orifice is located at the satellite equator to permit free diffusion of atmosphere gases between the chamber interior and the atmosphere. The spherical chamber is connected through a high-conductance tube to a quadrupole mass-spectrometer sensor to permit accurate quantitative evaluation of the density of the gas.

Spencer, N. W.↗
DOE OSTI2023

OH density, flux and loss probability measurements in a room temperature atmospheric pressure surface discharge by microscopic laser induced fluorescence

Many applications involving atmospheric pressure plasma-substrate interactions are enabled by the large fluxes of short-lived reactive species such as OH radicals to the substrate, nonetheless, the accurate measurement of radical densities and fluxes at substrates at atmospheric pressure has received little attention to date, particularly for surface ionization waves. We report the measurement of the OH density distribution in a surface discharge on a fused silica (quartz) substrate generated by an impinging atmospheric pressure plasma jet in dry and humid helium. The OH density is measured by microscopic laser induced fluorescence with a spatial resolution of 10 µm in the direction perpendicular to the quartz substrate. The measured OH diffusive flux varied for the investigated experimental conditions by almost three orders of magnitude and had a maximum value of 1.7 × 10 15 cm -2 s -1 . The corresponding surface loss probability of OH on the quartz surface was determined to be ~0.01. The high spatial resolution was required to accurately resolve the near surface gradient of OH radicals.

plasma-surface interactions↗
NASA NTRS1973

Atmospheric temperature measurements by Raman laser scattering

System makes continuous synoptic measurement of air temperatures and temperature profiles from the ground in real time. Development is based on principle that intensity distribution of Raman scattered laser light is a function of temperature and it is theoretically possible to measure air temperature by analyzing its Raman spectrum.

Masica, W. J.↗