ONE-DIMENSIONAL HYBRID SATELLITE TRACK MODEL FOR THE DYNAMICS-EXPLORER-2 (DE-2) SATELLITE

A one-dimensional hybrid satellite track model has been developed to c alculate the high-latitude thermospheric/ionospheric structure below t he satellite altitude using Dynamics Explorer 2 (DE 2) satellite measu rements and theory. This model is based on Emery et al. (1985) satelli te track code but also includes elements of Roble et al. (1987b) globa l mean thermosphere/ionosphere model. A number of parameterizations an d data handling techniques are used to input satellite data from sever al DE 2 instruments into this model. Profiles of neutral atmospheric d ensities are determined from the MSIS-90 model and measured neutral te mperatures. Measured electron precipitation spectra are used in an amo ral model to calculate particle impact ionization rales below the sate llite. These rates are combined with a solar ionization rate profile a nd used to solve the O+ diffusion equation, with the measured electron density as an upper boundary condition. The calculated O+ density dis tribution, as well as the ionization profiles, are then used in a phot ochemical equilibrium model to calculate the electron and molecular io n densities. The electron temperature is also calculated by solving th e electron energy equation with an upper boundary condition determined by the-DE 2 measurement. The model enables calculations of altitude p rofiles of conductivity and Joule heating rate along and below the sat ellite track. In a first application of the new model, a study is made of thermospheric and ionospheric structure below the DE 2 satellite f or a single orbit which occurred on October 25, 1981. The held-aligned Poynting flux, which is independently obtained for this orbit, is com pared with the model predictions of the height-integrated energy conve rsion rate. Good quantitative agreement between these two estimates ha s been reached. In addition, measurements taken at the incoherent scat ter radar site at Chatanika (65.1 degrees N, 147.4 degrees W) during a DE 2 overflight are compared with the model calculations. A good agre ement was found in lower thermospheric conductivities and Joule heatin g rate.