Non-local thermodynamic equilibrium in cloudy planetary atmospheres
Cloudy planetary atmospheres model, assessing nonlocal thermodynamic equilibrium role
Samuelson, R. E.↗
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Tables and charts of equilibrium thermodynamic properties of ammonia for temperatures from 500 to 50,000 K.
Equilibrium thermodynamic properties for pure ammonia were generated for a range of temperature from 500 to 50,000 K and pressure from 0.01 to 40 MN/sq m and are presented in tabulated and graphical form. Properties include pressure, temperature, density, enthalpy, speed of sound, entropy, molecular-weight ratio, specific heat at constant pressure, specific heat at constant volume, isentropic exponent, and species mole fractions. These properties were calculated by the method which is based on minimization of the Gibbs free energy. The data presented herein are for an 18-species ammonia model. Heats of formation and spectroscopic constants used as input data are presented. Comparison of several thermodynamic properties calculated with the present program and a second computer code is performed for a range of pressure and for temperatures up to 30,000 K.
Simmonds, A. L.↗
Tables and charts of equilibrium thermodynamic properties of carbon dioxide for temperatures from 100 K to 25,000 K
Equilibrium thermodynamic properties for pure carbon dioxide are presented in tabulated and graphical form for temperatures from 100 K to 25,000 K and pressures from 40 mN/sq m to 1 GN/sq m. Properties include pressure, temperature, density, enthalpy, speed of sound, entropy, molecular weight ratio, specific heat at constant pressure, specific heat at constant volume, isentropic exponent, and species mole fractions.
Miller, C. G., III↗
Radiative heating and cooling functions for the lower Martian atmosphere under the condition of Local Thermodynamic Equilibrium /LTE/
Carbon dioxide model for radiation heating and cooling functions of lower stratified Martian atmosphere in thermodynamic equilibrium
Pallmann, A. J.↗
Experimental evidence of departures from local thermodynamic equilibrium in arc plasmas at reduced pressure
Wall-stabilized arc for spectroscopic studies of departures from local thermodynamic equilibrium in argon and nitrogen plasmas at reduced pressures
Babrov, H. J.↗
Nonlocal thermodynamic equilibrium effects in stratospheric HF by collisional energy transfer from electronically excited O2 and implications for infrared remote sensing
A possible nonlocal thermodynamic equilibrium (non-LTE) effect involving stratospheric HF arising from the direct photochemical excitation of vibrationally excited HF by collisional energy transfer from electronically excited O2 is presented. Although this non-LTE effect is smaller that one associated with the direct solar excitation of both HF(nv = 1) and HF(nv = 2), calculations show that inclusion of the mechanism into retrieval algorithms is necessary if correct daytime upper stratosphere HF profiles are to be inferred in future IR thermal emission measurements.
Kaye, Jack A.↗
Non-local thermodynamic equilibrium limb radiance from O3 and CO2 in the 9-11 micrometer spectral region
Satellite remote sensing of mesospheric and thermospheric O3 abundance in the terrestrial atmosphere often uses 9-11 micrometer thermal emission. In this paper, we apply a line-by-line non-local thermodynamic equilibrium (non-LTE) radiance model to this spectral region and investigate the conditions of LTE breakdown and the effect that this has on the limb radiance measured by an i.r. sounder. Monochromatic and band-integrated radiance calculations have been performed for limb view tangent heights between 55 and 105 km under daytime and nighttime conditions. Non-LTE emission from both O3 and CO2 are shown to be important with the divergence of radiance from LTE values and the diurnal variation being band dependent. We have shown that the contribution of the CO2 bands to the Limb Infrared Monitor of the Stratosphere O3 channel is significant for daytime conditions at tangent heights above about 60 km. A study has been made to choose O3 sounding channel spectral passbands for the High Resolution Dynamics Limb Sounder. High resolution calculations are required to determine those spectral intervals that will filter radiance from selected bands and characterize their non-LTE behavior. This will allow for improved O3 retrievals above 70 km and non-LTE studies.
Edwards, David P.↗
Errors in Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) Kinetic Temperature Caused by Non-Local Thermodynamic Equilibrium Model Parameters
The vast set of near global and continuous atmospheric measurements made by the SABER instrument since 2002, including daytime and nighttime kinetic temperature (T(sub k)) from 20 to 105 km, is available to the scientific community. The temperature is retrieved from SABER measurements of the atmospheric 15 micron CO2 limb emission. This emission separates from local thermodynamic equilibrium (LTE) conditions in the rarefied mesosphere and thermosphere, making it necessary to consider the CO2 vibrational state non-LTE populations in the retrieval algorithm above 70 km. Those populations depend on kinetic parameters describing the rate at which energy exchange between atmospheric molecules take place, but some of these collisional rates are not well known. We consider current uncertainties in the rates of quenching of CO2 (v2 ) by N2 , O2 and O, and the CO2 (v2 ) vibrational-vibrational exchange to estimate their impact on SABER T(sub k) for different atmospheric conditions. The T(sub k) is more sensitive to the uncertainty in the latter two and their effects depend on altitude. The T(sub k) combined systematic error due to non-LTE kinetic parameters does not exceed +/- 1.5 K below 95 km and +/- 4-5 K at 100 km for most latitudes and seasons (except for polar summer) if the Tk profile does not have pronounced vertical structure. The error is +/- 3 K at 80 km, +/- 6 K at 84 km and +/- 18 K at 100 km under the less favourable polar summer conditions. For strong temperature inversion layers, the errors reach +/- 3 K at 82 km and +/- 8 K at 90 km. This particularly affects tide amplitude estimates, with errors of up to +/- 3 K.
Garcia-Comas, Maya↗
Evidence for nonlocal thermodynamic equilibrium in the nu3 mode of mesospheric ozone
Laboratory kinetic studies suggest that an appreciable fraction of the ozone produced by recombination of atomic oxygen is vibrationally excited in the nu3 mode. Further, laboratory data are available for the physical quenching of nu3, its radiative relaxation, and its radiative excitation by resonant absorption. It is shown that these chemical and physical processes are likely to result in substantial departures from local thermodynamic equilibrium for the nu3 mode of ozone in the mesosphere and therefore have important effects on infrared mesospheric ozone measurments by emission in the 9.6-micron band. Implications of these effects on data from the Limb Infrared Monitor of the Stratosphere (Remsberg et al, 1984), particularly their night/day ratio, are discussed.
Solomon, S.↗
Evidence from the limb infrared monitor of the stratosphere for nonlocal thermodynamic equilibrium in the nu2 mode of mesospheric water vapour and the nu3 mode of stratospheric nitrogen dioxide
Data from the 6.9-micron H2O channel and the 6.2-micron NO2 channel of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) have been used to investigate the daytime enhancement to H2O; the high concentration of H2O sometimes observed in the polar night mesosphere; and the high ratio of daytime to nighttime NO2 in the upper stratosphere. These three phenomena deviate noticeably from the predictions of photochemical theory. The 20 to 30 percent diurnal variation in stratospheric H2O apparent in LIMS data cannot be reconciled with a photochemical lifetime in excess of four months. This is attributed to departure from local thermodynamic equilibrium of daytime emission which had not been accounted for in retrievals. Speculative possibilities of NLTE emission from the H2O nu2 and NO2 nu3 hot bands are discussed. It is found that the nonthermal emission from NO2 significantly affects retrieval of H2O in the polar nighttime and NO2 in the daytime stratosphere at low latitudes.
Kerridge, Brian J.↗
Retrieval of Kinetic Temperature and Carbon Dioxide Abundance from Non-Local Thermodynamic Equilibrium Limb Emission Measurements made by the SABER Experiment on the TIMED Satellite
The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) experiment was launched onboard the TIMED satellite in December, 2001. SABER is designed to provide measurements of the key radiative and chemical sources and sinks of energy in the mesosphere and lower thermosphere (MLT). SABER measures Earth limb emission in 10 broadband radiometer channels ranging from 1.27 micrometers to 17 micrometers. Measurements are made both day and night over the latitude range from 54 deg. S to 87 deg. N with alternating hemisphere coverage every 60 days. In this paper we concentrate on retrieved profiles of kinetic temperature (T(sub k)) and CO2 volume mixing ratio (vmr), inferred from SABER-observed 15 micrometer and 4.3 micrometer limb emissions, respectively. SABER-measured limb radiances are in non-local thermodynamic equilibrium (non-LTE) in the MLT region. The complexity of non-LTE radiation transfer combined with the large volume of data measured by SABER requires new retrieval approaches and radiative transfer techniques to accurately and efficiently retrieve the data products. In this paper we present the salient features of the coupled non-LTE T(sub k)/CO2 retrieval algorithm, along with preliminary results.
Mertens, Christopher J.↗
Non-Equilibrium Thermodynamic Chemistry and the Composition of the Atmosphere of Mars
A high priority objective of the Mars Exploration Program is to Determine if life exists today (MEPAG Goal I, Objective A). The measurement of gases of biogenic origin may be an approach to detect the presence of microbial life on the surface or subsurface of Mars. Chemical thermodynamic calculations indicate that on both Earth and Mars, certain gases should exist in extremely low concentrations, if at all. Microbial metabolic activity is an important non-equilibrium chemistry process on Earth, and if microbial life exists on Mars, may be an important nonequilibrium chemistry process on Mars. The non-equilibrium chemistry of the atmosphere of Mars is discussed in this paper.
J S Levine↗
Thermodynamic equilibrium and the inorganic origin of organic compounds.
Formation of organic compounds under conditions of thermal equilibrium, noting aromatic compounds in solar nebula and gases activated to plasma state
SOLAR NEBULA↗
Tables and charts of equilibrium thermodynamic properties of carbon dioxide for temperatures to 25,000 K
Properties considered for the pure gas are: (1) pressure; (2)temperature,(3) density, (4) enthalpy, (5) speed of sound; (6) entropy, (7) molecular weight ratio, (8) specific heat at constant pressure; (9) specific heat at constant volume; (1) isentropic exponent and (11) species mole fractions.
Wilder, S. E.↗
Some applications of equilibrium thermodynamic properties to continuum gasdynamics
The speed of sound for the propagation of isentropic disturbances in a gas is developed, including corrections for chemical reaction. The term zero frequency is used to describe this isentropic limit sound speed; the term signifies that change in the gasdynamic variables are all very slow compared with the chemical rate changes in the gas. A faster, nonisentropic speed of propagation occurs for disturbances where the changes in gasdynamic variables are fast compared with the chemical rate changes. In the limit, this is known as the infinite frequency or frozen sound speed - the former term calling attention to the very high frequency of the disturbance, the latter term calling attention to the frozen character of the chemical reactions under such rapid changes of state. The true sound speed for a disturbance of finite frequency is shown to be between these two limits and is expressed in terms of the chemical relaxation time. The Riemann invariants that are useful in determining the changes in flow speed along characteristic directions in supersonic flow are derived in terms of integrations of acoustic impedance, and example results are given for air.
Source record↗
Invalidity of local thermodynamic equilibrium for electrons in the solar transition region. I - Fokker-Planck results
(Previously announced in STAR as N83-17439)
Shoub, E. C.↗
Nonlocal thermodynamic equilibrium effects in stratospheric NO and implications for infrared remote sensing
It is shown that the vibrational state population of stratospheric nitric oxide (NO) could be substantially different from that expected on the basis of LTE. Deviations from LTE may arise because stratospheric NO can be photochemically produced from NO2 with several vibrational quanta. Model calculations suggest that the population of NO(v = 1) could be some 30 percent above that expected from LTE at 30 km, with smaller enhancements above and below. Substantially larger enhancements are predicted for NO(v = 2). This result is shown to have important implications for NO determination by remote sensing of IR emission. Data needed for the quantification of these effects are enumerated.
Kaye, Jack A.↗
The development of flux-split algorithms for flows with non-equilibrium thermodynamics and chemical reactions
A finite-volume method for the numerical computation of flows with nonequilibrium thermodynamics and chemistry is presented. A thermodynamic model is described which simplifies the coupling between the chemistry and thermodynamics and also results in the retention of the homogeneity property of the Euler equations (including all the species continuity and vibrational energy conservation equations). Flux-splitting procedures are developed for the fully coupled equations involving fluid dynamics, chemical production and thermodynamic relaxation processes. New forms of flux-vector split and flux-difference split algorithms are embodied in a fully coupled, implicit, large-block structure, including all the species conservation and energy production equations. Several numerical examples are presented, including high-temperature shock tube and nozzle flows. The methodology is compared to other existing techniques, including spectral and central-differenced procedures, and favorable comparisons are shown regarding accuracy, shock-capturing and convergence rates.
Grossman, B.↗