Neutral atmospheric composition between 60 and 220 km: A theoretical model for mid-latitudes
Abstract
A new theoretical model for mid-latitude mesosphere and lower thermosphere at equinox conditions has been developed by including new values of various characteristic atmospheric parameters. A value of the eddy diffusion coefficient was deduced compatible with others reported in the literature and we discuss its effect upon the concentration of the different constituents. Photodissociation processes were handled with a detailed division of the different regions of the solar spectrum, mainly in the Schumann-Runge bands, allowing an exact computation of the diurnal O( 1D) and O2( 1Δ g) altitude profiles produced by solar radiation. The model includes CO, CO 2, N 2 and oxygen and hydrogen compounds. Our results compare well with recent experimental altitude profiles of minor compounds at mesospheric levels. The altitude profiles have been tested to reproduce various nightglow features, such as the Infrared Atmospheric System of O2( 1Δ g) in 1.27 μm and the atomic oxygen green line. The resulting profiles are in line with results obtained using rocket borne instrumentation. In the thermosphere, the profiles agree with other more elaborate models restricted to this region and with mass spectrometer measurements. Diurnal variation of the concentrations is shown and explained in terms of photochemical and transport processes. Carbon compounds have been included to obtain a comprehensive model that can be used subsequently to obtain an interpretation of the effect of minor compounds on the population ofdifierent CO 2 excited levels giving rise to infrared emission at 4.3 and 15 μm.
- Publication:
-
Planetary and Space Science
- Pub Date:
- August 1986
- DOI:
- 10.1016/0032-0633(86)90126-1
- Bibcode:
- 1986P&SS...34..723R
- Keywords:
-
- Atmospheric Composition;
- Atmospheric Models;
- Mesosphere;
- Neutral Atmospheres;
- Thermosphere;
- Carbon Dioxide;
- Diffusion Coefficient;
- Diurnal Variations;
- Hydrogen Compounds;
- Oxygen Atoms;
- Ozone;
- Photodissociation;
- Schumann-Runge Bands;
- Solar Spectra;
- Temperate Regions;
- Turbulent Diffusion;
- Geophysics