[en] Zonal winds between altitudes of 25 and 120 km have been obtained from measurements of the Doppler shifts of lines of atmospheric gases in solar occultation spectra collected with the ATMOS spectrometer flown on Spacelab 3. Wind speeds of about 100 ms^-1 near 100 km and 25 to 50 ms^-1 between 25 and 70 km were observed at latitudes near 30 ⁰N and 50 ⁰S. The wind speeds were estimated to +- 5 ms^-1 and positions of the absorption lines relative to the rest frame of the instrument were simultaneously recovered to 5 x 10^-5 cm^-1. copyright American Geophysical Union 1987

[en] The water vapor content of the Mars atmosphere was measured from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) for a period of more than 1 Martian year, from June 1976 through April 1979. Results are presented in the form of global maps of column abundance for 24 periods throughout each Mars year. The data reduction incorporates spatial and seasonal variations in surface pressure and supplements earlier published versions of less complete data

[en] The Jet Propulsion Laboratory Mark IV interferometer recorded high-resolution, infrared solar spectra from the NASA DC-8 aircraft during flights over Antarctica in September 1987. The atmospheric absorption features in these spectra have been analyzed to determine the burdens of O₃, NO, NO₂, HNO₃, ClNO₃, HCl, HF, CO₂, CH₄, N₂O, HCN, CO, H₂O, CFCl₃, and CF₂Cl₂. The results show a collar of high HNO₃ and ClNO₃ surrounding a core in which the burdens of these and of HCl and NO₂ are very low. Clear increases in the burdens of HF and HNO₃ were observed during the course of September in the Vortex core. HCl and NO₂ exhibited smaller, less significant increases. The burdens of the tropospheric source gases, N₂O, CH₄, HCN, CFCl₃, CF₂Cl₂, CO, and H₂O, were observed to be much smaller over Antarctica than at mid-latitudes. This, together with the fact that HF over Antarctica was more than double its mid-latitude value, suggests that downwelling had occurred

[en] The attenuation of solar radiation between 1.8- and 15-μm wavelength was measured with the airborne Jet Propulsion Laboratory Mark IV interferometer during the Airborne Antarctic Ozone Expedition in 1987. The measurements not only provide information about the abundance of stratospheric gases, but also about the optical depths of polar stratospheric clouds (PSCs) at wavelengths of negligible gas absorption. The spectral dependence of the PSC optical depth contains information about PSC particle size and particle composition. Thirty-three PSC cases were analyzed and categorized into two types. Type I clouds contain particles with radii of about 0.5 μm and nitric acid concentrations greater than 40%. Type II clouds contain particles composed of water ice with radii of 6 μm and larger. Cloud altitudes were determined from 1.064-μm backscattering observations of the airborne Langley DIAL lidar system. Based on the PSC geometrical thickness, both mass and particle density were estimated. Type I clouds typically had visible wavelength optical depths of about 0.008, mass densities of about 20 ppb, and about 2 particles/cm³. The observed type II clouds had optical depths of about 0.03, mass densities of about 400 ppb mass, and about 0.03 particles/cm³. The detected PSC type I clouds extended to altitudes of 21 km and were nearly in the ozone-depleted region of the polar stratosphere. The observed type II cases during September were predominantly found at altitudes below 15 km

[en] A photochemical model consisting of 40 species and 107 reactions is integrated along 80 day air parcel trajectories calculated in the lower stratosphere for the springtime Antarctic. For the trajectory starting at 58 degree S, which may be regarded as outside the circumpolar vortex, only a small change in O₃ occurs in the model. In contrast, for the air parcel starting in the vortex at 74 degree S, the O₃ concentration is reduced by 93% during the 80 days from the beginning of August to late October. The model results for several species are compared with measurements from the Airborne Antarctic Ozone Experiment and, in general, good agreement is obtained. In the model, the denitrification of the air parcels in polar stratospheric clouds increases the amount of chlorine present in active form. Heterogeneous reactions maintain high active chlorine which destroys O₃ via the formation of the ClO dimer. Results of calculations with reduced concentrations of inorganic chlorine show considerably reduced O₃ destruction rates and compare favorably with the behavior of total O₃. The remaining major uncertainties in the photochemical aspects of the Antarctic ozone hole are highlighted

[en] The Atmospheric and Environmental Research, Inc., photochemical model has been used to simulate the concentrations and time development of key trace gases in the Antarctic stratosphere before, during, and after the Airborne Antarctic Ozone Experiment (AAOE). The model includes complete gas phase photochemistry and heterogeneous reactions of ClNO₃ (g) and N₂O₅ (g) with HCl (s) and H₂O (s). Observations of long-lived species by the AAOE instruments have been used to constrain the initial conditions in these calculations. The authors present results from four cases illustrating the evolution of the trace gases for a range of possible initial conditions and duration of heterogeneous activity. The amount of ClO produced by heterogeneous conversion of HCl is determined not only by the initial concentrations of NO_x (NO + NO₂ + NO₃),N₂O₅, and ClNO₃ during winter, but also by the rate at which NO_x is resupplied by photolysis of N₂O₅ and HNO₃, or by transport. Results from the four cases presented bracket column measurements of HCl, ClNO₃, and HNO₃ by the Jet Propulsion Laboratory and National Center for Atmospheric Research infrared spectrometers on board the NASA DC-8, and in situ measurements of ClO and NO_y by instruments aboard the NASA ER-2. Comparison of results and measurements of HCl and ClO suggests that heterogeneous chemistry was maintained throughout the month of September in 1987. They suggest field observations and kinetic data which would further constrain the photochemistry of the spring Antarctic stratosphere

[en] Measurements of the abundances of ozone over Antarctic in August and September 1987 obtained during the Airborne Antarctic Ozone Experiment are intercompared. These measurements of ozone concentrations and total column abundance were obtained by three satellite instruments, two IR and one UV column-measuring instruments aboard the DC-8, one in situ DC-8, and two in situ ER-2 instruments, an upward looking lidar aboard the DC-8, and ozonesondes from four sites in Antarctica. Given the natural variability of ozone in the Antarctic and the fact that the data were not truly coincident spatially and temporally, this intercomparison is suitable only for identifying gross disparities among the techniques, rather than confirming the accuracies as rigorously as is normally done in an intercomparison. This paper presents a summary of the ozone data, using the data and accuracies given by the individual investigators in the individual papers in this issue, without any attempt to critically review or evaluate the data. In general, very good agreement (within about 10-20%, limited by natural variability) among the various techniques was found, with no systematic biases detected. These observations confirm the low ozone amounts reported in the Antarctic stratosphere