摘要:

This special section ofJGR‐Planetscomprises representative invited and contributed papers originally presented at the Second International Conference on Laboratory Research for Planetary Atmospheres (2nd ICLRPA), held at the University of Virginia in Charlottesville on October 21, 1990. The purposes of such conferences include the identifications and reports of laboratory studies, required or accomplished, in support of planetary sciences. These studies are necessary for the derivation of meaningful data from spacecraft and ground‐based measurements and for mission plans generally. These conferences highlight progress in laboratory planetary sciences and emphasize the interdependence of laboratory research and modeling of planetary atmosphe

ISSN:0148-0227    

DOI:10.1029/91JE01679

年代:1991

数据来源: WILEY

摘要:

A new experimental technique which provides a laboratory environment much like that of the outer planets is described. More specifically this technique, collisional cooling, allows the study of the collisional properties of molecular species at temperatures which in ordinary spectroscopic cells would result in vanishingly small vapor pressures due to condensation. In this paper the basic theory of collisions is put forth, the experimental techniques described, and the results of pressure broadening studies for a number of species described.

ISSN:0148-0227    

DOI:10.1029/91JE01775

年代:1991

数据来源: WILEY

摘要:

Radiative transfer models which have been used to compute Jupiter's millimeter wave emission do not agree well with the existing radio astronomical observations (e.g., de Pater and Massie, 1985). This apparent discrepancy has gone largely unexplained due to a lack of laboratory absorption data at these wavelengths coupled with uncertainties in the calibration of millimeter wave observations. Gaseous ammonia (NH3) is the largest source of millimeter wave opacity on Jupiter. Previous laboratory measurements at 7.5‐ to 9.38‐mm were inconclusive as to which theoretical line shape most accurately describes the millimeter absorptivity of NH3(Joiner et al., 1989). We have made additional laboratory absorption measurements of gaseous ammonia at a shorter wavelength (3.2 mm) where the theoretical line shapes can be better evaluated. We have conducted measurements at a temperature of 210 K, at pressures ranging from 1 to 2 atm, and in a mixture consisting of 85.56% hydrogen (H2), 9.37% helium (He), and 5.07% ammonia (NH3). We give a revised formalism for computing NH3absorption in an H2/He atmosphere using the Ben‐Reuven line shape. We investigate several other potential millimeter wavelength absorbers and give revised formalisms for computing their absorption. We have compiled a list of Jupiter's reliable millimeter wavelength observations. We compare our list of observations with synthetic emission spectra utilizing our revised expressions for computing absor

ISSN:0148-0227    

DOI:10.1029/91JE01740

年代:1991

数据来源: WILEY

摘要:

Recent observations of the millimeter wave (2.6 mm) emission from Venus have shown significant variations in its continuum flux emission (de Pater et al., 1991). Some of this change in emission may be attributed to variability in the abundance of Venus cloud constituents, specifically H2SO4condensates. In order to evaluate this hypothesis, a knowledge of the dielectric properties of liquid sulfuric acid at millimeter wave frequencies (30

ISSN:0148-0227    

DOI:10.1029/91JE01684

年代:1991

数据来源: WILEY

摘要:

We made thin film transmission measurements of solid CH4(phases I and II) and C2H6(phase II). From these, the complex indices of refraction at near‐ and mid‐infrared wavelengths were determined by using a combined least squares and Kramers‐Kronig ana

ISSN:0148-0227    

DOI:10.1029/91JE01741

年代:1991

数据来源: WILEY

摘要:

High‐resolution measurements of widths and shifts of vibrational‐rotational lines in infrared spectra of gaseous methane have been made in the laboratory. This research introduced at ambient temperatures the rare gases helium, neon, argon, krypton, and xenon and the diatomics hydrogen, nitrogen, oxygen, and carbon monoxide at pressures from 100 to 700 torr Detailed quantitative studies of correlations with masses, polarizabilities and quadrupole moments suggest that there may be some functional dependences on these physical paramet

ISSN:0148-0227    

DOI:10.1029/91JE01678

年代:1991

数据来源: WILEY

摘要:

The laboratory infrared spectrum of13C mono‐substituted ethane has been obtained at high resolution (0.0025 cm−1) using the McMath Fourier transform spectrometer at Kitt Peak National Observatory in May 1990. A preliminary analysis of the ν12rQ0branch (substituted species) suggests that its intensity is 1.15±0.05 times stronger than the equivalent ν9branch in the normal12C2H6species. This result leads to a correction of a previously published estimate for the12C/13C ratio in the atmosphere of Jupiter from ∼94

ISSN:0148-0227    

DOI:10.1029/91JE01742

年代:1991

数据来源: WILEY

摘要:

The presence of acetylene has been confirmed for some time in the atmospheres of the outer planets Jupiter, Saturn, Neptune, and Saturn's satellite Titan. For these atmospheres, the determination of C2H2abundances using its strong ν5fundamental requires laboratory line position and intensity measurements. The 1‐meter Fourier transform spectrometer at McMath solar telescope of Kitt Peak National Observatory was used to measure C2H2at an unapodized spectral resolution of 0.0025 cm−1. Synthetic spectra are generated by convolving a Voigt line shape with an instrument function and varying intensity parameters by means of a nonlinear least squares technique. Intensities of 37 ν5lines spanningP18 throughR20 were measured using 0.123 torr of gas in a 1‐cm cell. A Herman‐Wallis intensity correction parameter A1pr= 1.3(4) × 10−3has been derived using a least square

ISSN:0148-0227    

DOI:10.1029/91JE01773

年代:1991

数据来源: WILEY

摘要:

Thermal emission from the deep atmosphere of Venus can be detected on the nightside around 2.3 μm. The analysis of this radiation requires a reliable knowledge of the absorption in the far wings of the nearby allowed CO2bands and of the absorption due to collision‐induced bands. We measured absorption coefficients for pure CO2at pressures varying from 30 to 60 bars in the frequency range 3910–4570 cm−1at 297.5 K. Values between 1.0 and 1.6 × 10−7cm−1amagat−2are found in the 4100–4500 cm−1interval where emission from the Venus nightside occurs. The comparison of experimental results with synthetic spectra calculated from a line by line code demonstrates that the Lorentzian line shape strongly overestimates the observed absorption, whereas the use of a χ factor extrapolated from the 3800–4000 cm−1region does not

ISSN:0148-0227    

DOI:10.1029/91JE01680

年代:1991

数据来源: WILEY

摘要:

Recent progress related to the modeling of various pressure‐induced absorption bands of binary molecular systems, involving dissimilar and like pairs of molecules such as H2, He, N2, CH4, etc., is reported. The notes include references to the existing efforts based on quantum line shape computations that reproduce the laboratory measurements of pressure‐induced absorption closely. The results may be considered a most reliable data base permitting an evaluation of pressure‐induced absorption as function of frequency, temperature, and gas density for various binary molecular systems and spectral bands in the infrared region of the spe

ISSN:0148-0227    

DOI:10.1029/91JE01683

年代:1991

数据来源: WILEY