The Effect of Mixing Upon Atomic and Molecular Oxygen in the 70–170 km Region of the Atmosphere
01 Aug 1970-Journal of the Atmospheric Sciences (American Meteorological Society)-Vol. 27, Iss: 5, pp 831-840
TL;DR: In this paper, the coupled non-steady state equations of motion and continuity, including a time varying solar flux, were solved for [0] and [O2] in the altitude region between 70 and 170 km and for argon over the altitude range 0 to 170 km.
Abstract: The coupled non-steady-state equations of motion and continuity, including a time varying solar flux, are solved for [0] and [O2] in the altitude region between 70 and 170 km and for argon over the altitude range 0 to 170 km. Measured atmospheric temperature, diffusion coefficients (molecular and eddy), and the total density as determined from chemical trail releases (85–170 km) are used as the atmospheric transport coefficients in the equations of motion. The calculations show the effect of mixing in the form of a variable vertical eddy diffusion coefficient upon the previously calculated large time constants of [0] in this critical altitude region. This now permits the establishment of diurnal reproducibility on all constituents where steady-state solutions are not possible, i,e., [O] and [02].
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TL;DR: In this article, the atomic oxygen distribution as a function of altitude between 80 and 120 km was deduced from Ogo 6 557.7-nm airglow photometer data obtained between August 1969 and April 1970.
Abstract: The atomic oxygen distribution as a function of altitude between 80 and 120 km and as a function of latitude has been deduced from Ogo 6 557.7-nm airglow photometer data obtained between August 1969 and April 1970. The results indicate that the density ranges from 15 to 50 billion per cu cm at 120 km; that there is a semiannual variation by a factor of 3 in the global average density near 100 km in phase with the satellite drag semiannual effect; and that large latitudinal variations occur with maximums between 40 and 60 deg in the winter hemisphere and sometimes deep minimums in the tropics. The implication of these results for meridional and vertical transport patterns is discussed.
137 citations
TL;DR: In this article, the mean height profiles of fundamental turbulence parameters in the region 80-120 km were presented, and measured turbulent energy dissipation rates and eddy diffusion coefficients were collated.
106 citations
TL;DR: In this paper, the root-mean-square fluctuating velocities of radio wave scatterers in the altitude range 80-100 km have been recorded about every 2 to 3 hours.
Abstract: Since February 1985, the 2-MHz narrow beam radar near Adelaide, Australia, has been used to measure the short-term root-mean-square fluctuating velocities of radio wave scatterers in the altitude range 80–100 km. Data have been recorded about every 2 to 3 hours. This is in addition to the routine measurement of winds in the region between 60 and 100 km altitude. Under certain assumptions, these fluctuating velocities can then be converted to turbulent energy dissipation rates and eddy diffusion coefficients. These measurements are presented, and their interpretation as turbulence is discussed. The possibility of contamination from high frequency, short wavelength gravity waves is considered and a correction procedure to allow for such contamination is developed. It is concluded that the corrected measurements represent a good indication of turbulence activity. Between 84 and 92 km, the turbulence intensities were approximately constant with increasing height, but between 80 and 84 km turbulence was relatively weak. Seasonal variations are discussed, and important interannual differences between 1985 and 1986 are noted.
94 citations
TL;DR: In this article, the effects of the profile of the effective eddy diffusion coefficient on the height variations in O, O 2 and He number densities were considered, and it was shown that the reduction of [O] is particularly pronounced when the eddy coefficient has a peak near 100 km.
88 citations
Abstract: Calculations have been made of the diurnal variations in minor neutral constituents in the mesosphere and lower thermosphere for the condition of 60 deg latitude, summer and winter. Excited molecular oxygen has been added, and the effects of absorption of Schumann-Runge bands have been taken into account. The results show significant seasonal differences, which may be interpreted mainly in terms of the difference of penetration of solar radiation and the duration of sunlit hours. However, the comparison of the observed seasonal and diurnal variations in the airglow emissions from hydroxyl, atomic oxygen (5577 A), and excited molecular oxygen with those calculated from models suggests that effects of large-scale meridional circulation (horizontal and vertical transports) may be important in explaining these observations. It is shown that the concentration of the constituents whose main loss mechanism is recombination with atomic oxygen decreases sharply above 80 km.
83 citations