Mid‐ and low‐latitude model of thermospheric emissions: 1. O+ (²P) 7320 Å and N2 (2P) 3371 Å

The capability has been developed to model thermospheric airglow emissions on a semiglobal scale (L < 5). This model produces volume emission rates as a function of altitude, latitude, longitude, and local time for any selected date, and solar and magnetic conditions. The model can thus be used to provide three-dimensional maps of the selected emission for comparison with data obtained from orbiting vehicles. As such it becomes an essential tool in the planning and interpretation of airglow observations. A unique feature of the model is that it incorporates full interhemispheric coupling by solving all the appropriate coupled equations along the magnetic flux tubes from the mesosphere in one hemisphere to the mesosphere in the other hemisphere. As a result the effects of conjugate photoelectrons (and heat fluxes) can be fully explored. In this paper we select two thermospheric emissions with which to demonstrate the capability. The first is the 7320-A emission from the metastable O+ (²P). The second is the permitted emission at 3371 A from the N2 second postive 0–0 band. These two emissions, for which the photochemistry is relatively well understood, are used to show the seasonal, diurnal and solar cyclic variations on a scale that covers mid- and low-latitudes, and the effects of interhemispheric coupling (conjugate photoelectrons).

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