Robert W. Boese

Intensity measurements and rotational intensity distribution for the oxygen A-band

Abstract Quantitative measurements of intensities and half-widths have been made for individual rotational lines of the atmospheric oxygen A-band. The total band intensity, as derived from the line intensity measurements, is 532 cm-1 km-1 atm-1 STP. The line half-widths at half intensity were determined by two methods for the PQ and PP branch lines and are found to vary from about 0.05 cm-1 atm-1 near the origin to 0.04 cm-1 atm-1 for high K″ values. The rotational intensity distribution is demonstrated to conform more closely to the theoretical Honl-London factors calculated by either Schlapp or by Watson rather than those found experimentally by Childs and Mecke.

Intensity measurements, self-broadening coefficients, and rotational intensity distribution for lines of the oxygen B band at 6880 Å

Abstract Quantitative measurements of intensities and half-widths were made for individual rotational lines of the atmospheric oxygen B band. The total band intensity, as derived from the line intensity measurements, is 40·8±0·6 cm −1 km −1 atm −1 STP. As had been previously found in this laboratory for the oxygen A band, the relative line intensities conform closely to the rotational distribution calculated by either Schlapp or by Watson. The line half-widths at half-intensity were determined for oxygen self-broadening for the P Q and P P branch lines and for a few R Q and R R branch lines near the band origin, and were found to vary from 0·064 cm −1 atm −1 at J ′ = 1 to 0·042 cm −1 atm −1 at J ′ = 25.

Net thermal radiation in the atmosphere of Venus

Abstract The four entry probes of the Pioneer Venus mission measured the radiative net flux in the atmosphere of Venus at latitudes of 60°N, 31°S, 27°S, and 4°N. The three higher latitude probes carried instruments (small probe net flux radiometers; SNFR) with external sensors. The measured SNFR net fluxes are too large below the clouds, but an error source and correction scheme have been found (H. E. Revercomb, L. A. Sromovsky, and V. E. Suomi, 1982, Icarus 52, 279–300) . The near-equatorial probe carried an infrared radiometer (LIR) which viewed the atmosphere through a window in the probe. The LIR measurements are reasonable in the clouds, but increase to physically unreasonable levels shortly below the clouds. The probable error source and a correction procedure are identified. Three main conclusions can be drawn from comparisons of the four corrected flux profiles with radiative transfer calculations: (1) thermal net fluxes for the sounder probe do not require a reduction in the Mode 3 number density as has been suggested by O. B. Toon, B. Ragent, D. Colburn, J. Blamont, and C. Cot (1984, Icarus 57, 143–160) , but the probe measurements as a whole are most consistent with a significantly reduced mode 3 contribution to the cloud opacity; (2) at all probe sites, the fluxes imply that the upper cloud contains a yet undetected source of IR opacity; and (3) beneath the clouds the fluxes at a given altitude increase with latitude, suggesting greater IR cooling below the clouds at high latitudes and water vapor mixing ratios of about 2–5 × 10−5 near 60°, 2–5 × 10−4 near 30°, and 5 × 10−4 near the equator. The suggested latitudinal variation of IR cooling is consistent with descending motions at high latitudes, and it is speculated that it could provide an important additional drive for the general circulation.

Temperature dependence of intensities of the 8–12 μm bands of CFCl3

Abstract The absolute intensities of the 8–12 μm bands from freon 11 (CFCl 3 ) were measured at temperatures of 294 and 216°K. Intensities of the bands centered at 798, 847, 934, and 1082 cm -1 are all observed to depend on temperature. The temperature dependence for the 847 and 1082 cm -1 fundamental regions is attributed to underlying hot bands; for the ν 2 + ν 5 combination band (934 cm -1 ), the observed temperature dependence is in close agreement with theoretical prediction. The implication of these results on atmospheric i.r. remote-sensing is briefly discussed.

Nature of the ultraviolet absorber in the venus clouds: inferences based on pioneer venus data.

Several photometric measurements of Venus made from the Pioneer Venus orbiter and probes indicate that solar near-ultraviolet radiation is being absorbed throughout much of the main cloud region, but little above the clouds or within the first one or two optical depths. Radiative transfer calculations were carried out to simulate both Pioneer Venus and ground-based data for a number of proposed cloud compositions. This comparison rules out models invoking nitrogen dioxide, meteoritic material, and volatile metals as the source of the ultraviolet absorption. Models involving either small (∼1 micrometer) or large (∼10 micrometers) sulfur particles have some serious difficulties, while ones invoking sulfur dioxide gas appear to be promising.

Absolute intensities and pressure broadening coefficients measured at different temperatures for the 201II ← 000 band of 12C16O2 at 4978cm-1

Absolute line intensities and self-broadening coefficients have been measured at 197° and 294°K for the 201II ← 000 band of 12C16O2 at about 4978cm-1. The vibration-rotation factor (FVR), the purely vibrational transition moment (∣R(O)∣), and the integrated band intensity (Sband) are deduced from the measurements. The results are: FVR(m)=1+(0.24±0.08)x10-4m+(0.55+0.21)x10-4m2, ∣R(O)∣= (4.340±0.008x10-3 debye, Sband=96372±190cm-1km-1atm-1STP. The results for self-broadening coefficients, as well as for individual vibration-rotation lines, are presented in the text.

A laboratory atlas of the 5ν1 NH3 absorption band at 6475 Å with applications to Jupiter and Saturn

Abstract The 5 ν 1 absorption band of NH 3 is displayed from 6418 to 6550 A. The total band intensity has been measured: S B = 0.66 cm −1 m −1 amagat −1 . Line intensities and self-broadening coefficients have been measured for some of the prominent lines. Our line intensities are in good agreement with those of Rank et al . (1966) , but are about 2 times greater than those of Mason (1970) . The spectrum displayed was obtained photoelectrically at a pressure of 0.061 atm, and shows many more lines than the spectrum obtained by McBride and Nicholls (1972a) at a pressure of 0.39 atm. Therefore, our new measurements can provide the basis for making a more complete rotational analysis than those of McBride and Nicholls (1972a) . Since the total band absorption has previously been measured by others on moderate resolution photoelectric scans of the spectra of Jupiter and Saturn, we can use the band intensity to derive the NH 3 abundance in the atmospheres of these two planets. The NH 3 abundances in a single vertical path obtained by this method are about 10m amagat for Jupiter and 2m amagat for Saturn. These results are in agreement with previous results obtained from higher resolution photographic spectra.

First Results from the Large Probe Infrared Radiometer Experiment

During the descent to the surface of Venus, the large probe infrared radiometer measured the net thermal radiative flux in several spectral bandpasses. Preliminary analysis has permitted us to estimate (i) the infrared extinction coefficient profile attributable to aerosols, with respect to their visible profile, in the upper atmosphere of Venus and (ii) the water vapor mixing ratio below the clouds. An indication of the composition of a multicomponent cloud is seen in the data from the spectral bandpass from 6 to 7 micrometers.

Temperature dependence of HNO 3 absorption in the 11.3-μm region

Laboratory spectra have been obtained for HNO3 with a Michelson-type Fourier transform interferometer using absorption cells with path lengths of 10.3, 25.5, and 49.8 cm at temperatures of 240, 248, 283, and 294 K. The measurements lead to a total band intensity value of 642 plus or minus 5% per sq cm amagat, which is a temperature independent value after the gas density correction has been made. However, the temperature dependence of the spectral absorption coefficients is apparent in the 885 kayser region.

Intensities and half-widths at different temperatures for the 201III←000 band of CO2 at 4854 cm−1☆

Abstract Measurements made at temperatures of 197, 233, and 294°K of the absolute intensities and self-broadening coefficients for the vibration-rotation lines of the 201III←000 band of the 12C16O2 molecule, are reported. From these measurements, values have been derived for the vibration-rotation interaction factor (FVR), the purely vibrational transition moment (|R(O)|), and the intensity (SBand). The results are: EVR(m) = 1+(2.2±0.7)×10−3 m+(5.6±1.6)×10×5m2, |R(0)| = (2.064±0.017)×10−3 debye, SBand = 21,329±69 cm−1 km−1 atm−1STP. The results for the self-broadening coefficients are presented in the text.