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No abstract available

No abstract available

[en] A detailed study of ethane and ethylene photochemistry is presented for the troposphere and stratosphere. It is demonstrated that the loss of ethane is controlled by OH in the troposphere and Cl in the stratosphere. Observation of ethane show a stratospheric behavior indicative of a free chlorine concentration below 30 km that is only 10% of the predicted value given by both our photochemical model calculations and those done by others. The inferred lower amount of chlorine cannot be explained by heterogeneous processes for concentration of aerosols representing average background conditions, nor does current stratospheric photochemistry show agreement. Chemical destruction of ethane and ethylene within the atmosphere leads to the production of carbon monoxide, formaldehyde, and other products. Tropospheric concentrations of formaldehyde are enhanced by nearly a factor of 3 for an ethylene mixing ratio of 2 ppb. Simultaneous monitoring of formaldehyde and carbon monoxide, as well as other products, will greatly aid in determining the relative importance of different tropospheric CO sources. Peroxyacetyl nitrate (PAN) acts as a reservoir for odd-nitrogen at the expense of HNO₃ HO₂NO₂, NO, and NO₂

[en] The first effects of a nearby (approximately10 parsec) supernova on the Earth's atmosphere will be caused by ultraviolet radiation dissociating molecular oxygen. The event will be of about one month's duration. Several months later nuclear gamma radiation may arrive, causing a decrease in atmospheric ozone. Cosmic radiation from the supernova remnant will not intercept the Earth for at least 1000 years at which time ozone will be seriously depleted. Supernova ultraviolet radiation increases column ozone and atomic oxygen. Atmospheric thermal structure is modified with a large temperature increase in the mesosphere and lower thermosphere and a decrease at higher altitudes caused by enhanced heat loss due to atomic oxygen radiation and conduction. (author)

No abstract available

No abstract available

[en] The u.v. spectrometer polarimeter on the Solar Maximum Mission has been utilized to measure mesospheric ozone vs altitude profiles by the technique of solar occultation. Sunset data are presented for 1980, during the fall equinoctal period within +-20deg of the geographic equator. Mean O₃ concentrations are 4.0 x 10¹⁰ cm^-3 at 50 km, 1.6 x 10¹⁰ cm^-3 at 55 km, 5.5 x 10⁹ cm^-3 at 60 km and 1.5 x 10⁹ cm^-3 at 65 km. Some profiles exhibit altitude structure which is wavelike. The mean ozone profile is fit best with the results of a time-dependent model if the assumed water vapor mixing ratio employed varies from 6 ppm at 50 km to 2-4 ppm at 65 km. (author)

[en] Rocket observations of the lower ionosphere in the winter 1971 at two locations show differences of electron density which are attributed to enhancements of nitric oxide and energetic electron fluxes precipitated into the mesosphere during the poststorm phase of a geomagnetic storm. Electron density distributions were observed above Wallops Island, Virginai, and Keweenaw, Michigan, larger values occurring at Keweenaw. Energetic electron fluxes were greater at Keweenaw (L=3.9) than at Wallops Island (L=2.5). While particle ionization was the dominant factor in establishing the electron density during one measurement at Keweenaw, particles were not present 2 day earlier, even though the electron density distribution was significantly larger than that observed at Wallops Island on both occasions. An accompanying ion composition profile measured at Keweenaw during the earlier flight showed NO¹ to be the dominant ion to 76 km, where the concentration of hydrated ions, H₃O¹x (H₂O)/sub n/, exceeded that of NO. This lowering of the transition height from NO¹ to hydrated species is in agreement with independent observations of D region ion composition during anomalous winter conditions

[en] The compounds C₄H₂, HC₃N, and C₂N₂ have been detected in trace amounts in the stratosphere of Titan. The identification of two compounds containing nitrogen, in addition to HCN, provides further evidence for the abundance of free N₂ on Titan. (author)