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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Studies in upper and lower atmosphere coupling

The theoretical and data-analytic work on upper and lower atmosphere coupling performed under a NASA Headquarters contract during the period April 1978 to March 1979 are summarized. As such, this report is primarily devoted to an overview of various studies published and to be published under this contract. Individual study reports are collected as exhibits. Work performed under the subject contract are in the following four areas of upper-lower atmosphere coupling: (1) Magnetosphere-ionosphere electrodynamic coupling in the aurora; (2) Troposphere-thermosphere coupling; (3) Ionosphere-neutral-atmosphere coupling; and (4) Planetary wave dynamics in the middle atmosphere.

Chiu, Y. T.↗
NASA NTRS1991

Energy balance and plume dynamics in Triton's lower atmosphere

The present study of the thermal balance-affecting relationships among Triton lower atmosphere thermal conduction, eddy mixing, condensation, and radiative heating indicates that, while the temperature gradient is negative in the lower atmosphere, it becomes positive at higher altitudes due to the downward conduction of ionospheric heat. This temperature profile is essentially consistent with radio-occultation experiment data; the geyser-like plumes observed by Voyager suggest that the Trioton atmosphere's convective and conductive regions join near 10-km altitude, and that the values inferred for the eddy diffusion and heat-transport coefficients indicate a profile reminiscent of the earth's.

Yelle, Roger V.↗
NASA NTRS1983

Sulfur trioxide in the lower atmosphere of Venus

Inconsistencies and ambiguities are noted by the present consideration of Pioneer Venus and Venera atmospheric composition measurement of Venus in the context of lower atmosphere thermodynamic equilibrium. Among the scenarios projected on the basis of assumed correctness for selected data subsets, the O2 and SO2 concentrations reported by the Pioneer Venus chromatograph and the H2O concentrations reported by Venera 11 suggest that large concentrations of SO3 are present in the lower atmosphere of Venus. Such SO3 concentrations lead, however, to difficulties in explaining the atmosphere at and above the cloud tops, and in addition require specific assumptions concerning chemical reaction rates at and near the surface.

Craig, R. A.↗
DOE OSTI2024

Low-Level Liquid-Bearing Clouds Contribute to Seasonal Lower Atmosphere Stability and Surface Energy Forcing over a High-Mountain Watershed Environment

Measurements of atmospheric structure and surface energy budgets distributed along a high-altitude moun tain watershed environment near Crested Butte, Colorado, from two separate, but coordinated, field campaigns, Surface Atmosphere Integrated field Laboratory (SAIL) and Study of Precipitation, the Lower Atmosphere, and Surface for Hydrometeorology (SPLASH), are analyzed. This study identifies similarities and differences in how clouds influence the radiative budget over one snow-free summer season (2022) and two snow-covered seasons (2021/22; 2022/23) for this alpine location. A relationship between lower-tropospheric stability stratification and longwave radiative flux from the presence or absence of clouds is identified. When low clouds persisted, often with signatures of supercooled liquid in win ter, the lower troposphere experienced weaker stability, while radiatively clear skies that are less likely to be influenced by liquid droplets were associated with appreciably stronger lower-tropospheric stratification. Corresponding surface turbu lent heat fluxes partitioned differently based upon the cloud–stability stratification regime derived from early morning radiosounding profiles. Combined with the differences in the radiative budget largely resulting from dramatic seasonal dif ferences in surface albedo, the lower atmosphere stratification, surface energy budget, and near-surface thermodynamics are shown to be modified by the effective longwave radiative forcing of clouds. The diurnal evolution of thermodynamics and surface energy components varied depending on the early morning stratification state. Thus, the importance of quies cent versus synoptically active large-scale meteorology is hypothesized as a critical forcing for cloud properties and associ ated surface energy budget variations. The physical relationships between clouds, radiation, and stratification can provide a useful suite of metrics for process understanding and to evaluate numerical models in such an undersampled, highly com plex terrain environment.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2017

Observations and Modeling of Thermal Structure in the Lower Atmosphere and the Upward Propagation of Tides into the Thermosphere

Thermal tides are the atmospheric response to diurnally varying thermal forcing resulting from radiative and convective heat transfer from the surface and from aerosol and gaseous heating within the atmosphere. Tides include sun-synchronous (migrating) waves driven in response to solar heating and additional non-migrating waves resulting from longitudinal variations in the distributions of topography, dust aerosol and water ice clouds. The systematic spatial mapping of temperature over 5 Mars years by the Mars Climate Sounder (MCS) has yielded a well-defined climatology of seasonally-varying temperature structures in the lower atmosphere, from 5 to ~80 km. Tide theory and Mars global circulation model (MGCM) simulations are a fruitful framework for relating temperature observations to thermal forcing by aerosol fields [1]. The analysis of density and temperature fields derived from MAVEN IUVS and NGIMS observations have revealed the presence of predominantly zonal wave 2 and 3 features at altitudes of 100-170 km that are almost certainly non-migrating tides propagating upward from the lower atmosphere [2,3]. In this presentation we will use the MCS climatology and MGCM simulations to relate the density variations seen by MAVEN with the seasonally varying tide activity in the lower atmosphere. Large amplitude perturbations in density are most sensitive to the tide components with the longest vertical wavelengths in temperature, which are well resolved in MCS observations.

Mars Climate Sounder (MCS)↗
NASA NTRS1973

Chemistry of the lower atmosphere

The presence of particulate matter in the lower atmosphere is considered, giving attention to the sources of particles in the troposphere, the composition of particles collected from the atmosphere, aspects of particle concentrations and size distributions, mechanisms of removal, residence times, and conditions in the lower stratosphere. The role of natural and anthropogenic pollutants in cloud and precipitation formation is discussed together with removal processes of gaseous and particulate pollutants, and the global sulfur cycle. Other topics examined include the chemical basis for climatic change and the carbon dioxide cycle. Individual items are announced in this issue.

Rasool, S. I.↗
NASA NTRS1986

Dissipative tides - Application to Venus' lower atmosphere

A linearized planetary scale wave model is used to investigate the effects of thermal and mechanical damping on atmospheric tides. When the damping rate is comparable to the frequency of solar diurnal forcing the circulation consists of three parts: a classical vertically propagating 'atmospheric tide' in the upper atmosphere, a simple thermally direct subsolar-to-antisolar circulation or 'Halley cell' in most of the lower atmosphere, and finally, a reversed 'anti-Halley cell' near the surface. The near-surface circulation produces horizontal divergence near the subsolar point. While tides are a frequently encountered phenomenon (Venus, earth, and Mars), there is so far no observational evidence of a Halley circulation in any planetary atmosphere. A subsolar-antisolar circulation might be possible in Venus' slowly rotating lower atmosphere if the mechanical dissipation time scale is of the order of or less than a Venusian day. Such a circulation could be a factor in maintaining the superrotation of Venus' upper atmosphere.

Covey, Curt↗
NASA NTRS1977

Distribution functions for energetic oxygen atoms in the earth's lower atmosphere

Direct photolysis of O3 and quenching of O(1D) by N2 provide abundant sources of fast oxygen atoms for earth's lower atmosphere. The concentration of atoms with energy above 0.7 eV may exceed the concentration of O(1D) for all altitudes below 18 km, and these atoms may play an important role in lower-atmospheric chemistry. Distribution functions for O(3P) are given for the energy interval 0.1-1.3 eV and a range of altitudes from 0 to 62 km.

Logan, J. A.↗
NASA NTRS2022

Contribution of the Lower Atmosphere to the Day-to-day Variation of Thermospheric Density

In this paper we carried out a numerical experiment using the Specified Dynamics mode of the Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (SD-WACCM-X). One SD-WACCM-X run was with realistic Kp and F10.7 and the other with constant Kp and F10.7. By comparing the day-to-day variability of thermosphere mass density at 300 km (low earth orbit, LEO) and 120 km (reentry level) in these two runs, we find that the density variation at 300 km is mainly driven by geomagnetic and solar forcing while at 120 km it is exclusively controlled by the lower atmosphere. At LEO altitudes, during solar minimum and geomagnetic quiet days, the impact from the lower atmosphere is much smaller than the effect of solar and geomagnetic variations but is not negligible (5–10% vs 20%).

Thermosphere Density↗
NASA NTRS1989

Balloon-borne characterization of the Martian surface and lower atmosphere

A recent NASA-sponsored design course at Utah State University (USU) has focused upon a Mars Lander/Rover system designed to descend from a Martian orbit and deploy both surface and balloon-borne instruments to examine the Martian surface and lower atmosphere. The latter stages of the USU design effort placed major emphasis on the design of the balloon rover. This paper presents the results of that emphasis by discussing the payload requirements, identification of the design parameters, surface vs. descent deployment, design tradeoff studies, site-influenced departures from the baseline design, the final design concept, and the resulting balloon performance. A single hydrogen superpressure balloon is selected for use in the design mission. The paper concludes that characterization of the Martian surface and lower atmosphere by a descent-deployed, balloon-borne rover is a viable concept that should be actively pursued.

Redd, F. J.↗
NASA NTRS1981

The thermal balance of the lower atmosphere of Venus

The temperature near the surface of Venus (now established at 730 K) is remarkably high in view of Venus's cloud cover which causes the planet to absorb even less sunlight than does Earth. Early attempts to understand the thermal balance that leads to this unusual state were hindered by the lack of basic information regarding the composition, temperature-pressure structure, cloud properties, and wind field of the lower atmosphere. A series of successful space missions have measured many of the above quantities that control the transfer of heat in Venus's lower atmosphere. The relevant observational data are summarized and the attempts to understand the thermal balance of Venus's atmosphere below the cloud tops are reviewed. The data indicate that sufficient sunlight penetrates to deep atmospheric levels and is trapped by the large thermal opacity of the atmosphere to essentially account for the high temperatures observed.

Tomasko, M. G.↗
NASA NTRS1983

The thermal balance of the lower atmosphere of Venus

The temperature near the surface of Venus (now established at 730 K) is remarkably high in view of Venus's cloud cover which causes the planet to absorb even less sunlight than does earth. Early attempts to understand the thermal balance that leads to this unusual state were hindered by the lack of basic information regarding the composition, temperature-pressure structure, cloud properties, and wind field of the lower atmosphere. A series of successful space missions have measured many of the above quantities that control the transfer of heat in Venus's lower atmosphere. The relevant observational data are summarized and the attempts to understand the thermal balance of Venus's atmosphere below the cloud tops are reviewed. The data indicate that sufficient sunlight penetrates to deep atmospheric levels and is trapped by the large thermal opacity of the atmosphere to essentially account for the high temperatures observed. Previously announced in STAR as N83-19672

Tomasko, M. G.↗