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Results for “ATMOSPHERIC HEATING”

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 NTRS1991

Middle atmosphere heating by exothermic chemical reactions involving odd-hydrogen species

The rate of heating which occurs in the middle atmosphere due to four exothermic reactions involving members of the odd-hydrogen family is calculated. The following reactions are considered: O + OH yields O2 + H; H + O2 + M yields HO2 + M; H + O3 yields OH + O2; and O + HO2 yields OH + O2. It is shown that the heating rates due to these reactions rival the oxygen-related heating rates conventionally considered in middle-atmosphere models. The conversion of chemical potential energy into molecular translational energy (heat) by these odd-hydrogen reactions is shown to be a significant energy source in the middle atmosphere that has not been previously considered.

Mlynczak, Martin G.↗
NASA NTRS1986

Steps towards understanding deep atmospheric heating in flares

Different aspects of the heating of the deep solar atmosphere during flares, including temperature minimum enhancements and white light emission, are discussed. The proper treatment of H(-) radiative losses is discussed, and compared with previous studies, as well as a quantitative analysis of the ionizing effect of nonthermal particles and ultraviolet radiation. It is concluded that temperature minimum heating may be a natural consequence of the global radiation transport in flares. The implications of these results are discussed within the context of homogeneous and inhomogeneous models of the solar atmosphere.

Mauas, Pablo J. D.↗
NASA NTRS1976

On the observed annual cycle in the ocean-atmosphere heat balance over the Northern Hemisphere

Based on the best presently available satellite radiation, atmospheric and oceanic data sets, the long-term mean heat balance of the earth and its normal seasonal variation are investigated over the Northern Hemisphere. Quantitative estimates for the various flux and storage terms in the atmospheric and terrestrial branches of the heat balance are given for 10-deg-wide latitude belts and for each calendar month. The results are presented in both graphical and tabular form. As was known before, the storage of heat in the oceans is found to dominate the energy storage in the combined atmosphere-ocean-land-cryosphere system. In the tropics, large changes in oceanic heat storage are found in the 10 N-20 N belt with a maximum in spring and a minimum in late summer. The main new finding of this study is that the inferred oceanic heat transports appear to undergo very large seasonal variations especially in the tropics.

Oort, A. H.↗
NASA NTRS1989

Interplanetary dust particles collected in the stratosphere - Observations of atmospheric heating and constraints on their interrelationships and sources

TEM and IR spectroscopy investigations of the interplanetary dust particles (IDPs) collected in the stratosphere have shown the majority of IDPs in the layer-lattice silicate and pyroxene classes to not have been heated to temperatures above 600 C during atmospheric entry. This implies that they arrive at the upper atmosphere with low geocentric encounter velocities, and limits the possible encounter trajectories for these particles to relatively circular prograde orbits. On this basis, it is judged unlikely that these IDPs are from earth-crossing comets or asteroids; collected IDPs dominated by olivine include a larger portion of above-600 C-heated particles, suggesting their capture from more eccentric orbits.

Sandford, Scott A.↗
NASA NTRS1975

The evaluation of a shuttle borne lidar experiment to measure the global distribution of aerosols and their effect on the atmospheric heat budget

A shuttle-borne lidar system is described, which will provide basic data about aerosol distributions for developing climatological models. Topics discussed include: (1) present knowledge of the physical characteristics of desert aerosols and the absorption characteristics of atmospheric gas, (2) radiative heating computations, and (3) general circulation models. The characteristics of a shuttle-borne radar are presented along with some laboratory studies which identify schemes that permit the implementation of a high spectral resolution lidar system.

Shipley, S. T.↗
NASA NTRS2022

Universal Scaling Laws for Solar and Stellar Atmospheric Heating: Catalog of Power-law Index between Solar Activity Proxies and Various Spectral Irradiances

The formation of extremely hot outer atmospheres is one of the most prominent manifestations of magnetic activity common to late-type dwarf stars, including the Sun. It is widely believed that these atmospheric layers, the corona, transition region, and chromosphere, are heated by the dissipation of energy transported upwards from the stellar surface by the magnetic field. This is signified by the spectral line fluxes at various wavelengths, scaled with power-law relationships against the surface magnetic flux over a wide range of formation temperatures, which are universal to the Sun and Sunlike stars of different ages and activity levels. This study describes a catalog of power-law indices between solar activity proxies and various spectral line fluxes. Compared to previous studies, we expanded the number of proxies, which now includes the total magnetic flux, total sunspot number, total sunspot area, and the F10.7 cm radio flux, and further enhanced the number of spectral lines by a factor of 2. This provides the data to study in detail the flux–flux scaling laws from the regions specified by the temperatures of the corona (log(T/K) = 6–7) to those of the chromosphere (log(T/K) ∼ 4), as well as the reconstruction of various spectral line fluxes of the Sun in the past, F-, G-, and K-type dwarfs, and the modeled stars.

Stellar coronae↗
NASA NTRS1975

Seasonal changes in the atmospheric heat balance simulated by the GISS general circulation model

Tests of the ability of numerical general circulation models to simulate the atmosphere have focussed so far on simulations of the January climatology. These models generally present boundary conditions such as sea surface temperature, but this does not prevent testing their ability to simulate seasonal changes in atmospheric processes that accompany presented seasonal changes in boundary conditions. Experiments to simulate changes in the zonally averaged heat balance are discussed since many simplified models of climatic processes are based solely on this balance.

Stone, P. H.↗
NASA NTRS1972

Atmospheric heating of meteors.

A theoretical model of the radiating metallic gas produced about an iron meteor entering the earth's atmosphere is discussed. Numerical results are presented for a 0.1 cm diameter iron meteor traveling at 15 km/sec at an altitude of 100 km above the earth. It is shown that collisions between the expanding iron gas and the air molecules produce a radiating gas shell a few meters thick which is located many meters ahead of the meteor core. Temperature, pressure, and density distributions are presented as functions of radial distance and angle for several initial meteor conditions.

Harwell, K. E.↗
NASA NTRS1990

The three-dimensional distribution of atmospheric heating during the GWE

The large-scale three-dimensional time-averaged distribution of heating and its temporal evolution as determined from the European Center for Medium-range Weather Forecasts (ECMWF) Global Weather Experiment (GWE) Level IIIb data set are examined. Global distributions of vertically averaged heating for January, April, July, and October 1979 are presented to illustrate the seasonal evolution of the planetary pattern. Horizontal distributions of heating and vertical profiles from various climatological regimes of the planetary circulation are given and provide insight into the four-dimensional structure of the thermal forcing of the atmosphere. Major features of the global distributions include heating in regions of deep moist convection over places such as South America. Seasonal meridional and zonal heating migration are discussed and it is noted that zonal migration is linked with planetary scale distribution of continents and oceans and the land-sea surface temperature distribution. Various degrees of heating in the troposphere and their consequences are investigated.

Schaack, Todd K.↗
NASA NTRS1986

Convection zone origins of solar atmospheric heating

Spicules are examined as a means for supplying the corona with mass, energy, and magnetic field. It is suggested that spicules form from the supersonic upward expansion of material on nearly evacuated network flux tubes embedded within the sun's convection zone. This allows supersonic but subescape velocities to be attained by the material as it flows outward through the photosphere. Although supersonic, the kinetic energy (subescape) of the spicule material, as observed, is insufficient for coronal heating. It is suggested that, through buoyancy changes on evacuated flux tubes, the magnetic field first 'wicks' material flow into the solar atmosphere. Subsequently, the magnetic field energizes the gaseous material to form the conventional hot, dynamically expanding, solar corona. This occurs through momentum and energy transport by Alfven waves and associated Maxwell stresses concurrently flowing upward on these 'geysers' (spicules). The vertical momentum equation governing fluid flow is examined, and a particular equipartition solution is presented for the flow velocity along a simple field geometry.

Schatten, Kenneth H.↗
NASA NTRS1975

Atmospheric heating by solar EUV radiation

A diurnal model of the mid-latitude ionospheric R region is used to calculate the diurnal variation of the neutral gas heating rates and neutral gas heating efficiency for conditions similar to those over Millstone Hill on March 23-24, 1970. The calculations show that the absorbed solar EUV (wavelength less than or equal to 1025 A) energy is almost equally split between photoelectrons and ion pair production. Photoelectrons heat the ambient electron gas by Coulomb collisions and by the quenching of certain excited ion species, whereas the ion gas is primarily heated by collisions with hot electrons and by chemical reactions. Heating processes above 300 km, between 170 and 300 km, and below 170 km are identified.

Stolarski, R. S.↗
NASA NTRS1991

Improved Prediction of Atmospheric Heating and Cooling Rates

The demands of accurate predictions of radiative transfer for climate applications are well-documented. While much effort is being devoted to evaluating the accuracy of the GCM radiative transfer schemes, the problem of developing accurate, computationally efficient schemes for climate models still remains. This paper discusses our efforts in developing accurate and fast computational methods for global and regional climate models.

Bergstrom, R. W.↗
NASA NTRS1993

An analysis of the Voyager 2 Ultraviolet Spectrometer occultation data at Uranus - Inferring heat sources and model atmospheres

Heat source information is derived here from the Voyager 2 Ultraviolet Spectrometer occultation data of Uranus. Analytic functions for the local heat dependence on altitude are used to obtain a temperature profile by solving the heat equation. The stellar entrance and exit occultation and a solar occultation are used to infer the thermal and density structure of the atmosphere. The least squares fit solution to the solar occultation data gives one source located at 1.8 x 10 exp -5 microbar with a strength of 0.056 +/- 0.01 erg/sq cm/s. Latitudinal temperature gradients are obtained.

Stevens, Michael H.↗
NASA NTRS1995

Study of magnetic notions in the solar photosphere and their implications for heating the solar atmosphere

This progress report covers the first year of NASA Grant NAGw-2545, a study of magnetic structure in the solar photosphere and chromosphere. We have made significant progress in three areas: (1) analysis of vorticity in photospheric convection, which probably affects solar atmospheric heating through the stresses it imposes on photospheric magnetic fields; (2) modelling of the horizontal motions of magnetic footpoints in the solar photosphere using an assumed relation between brightness and vertical motion as well as continuity of flow; and (3) observations and analysis of infrared CO lines formed near the solar temperature minimum, whose structure and dynamics also yield important clues to the nature of heating of the upper atmosphere. Each of these areas are summarized in this report, with copies of those papers prepared or published this year included.

Noyes, Robert W.↗