A technique for inferring lower thermospheric neutral density from meteoroid ablation

Abstract

In this paper, we present a novel technique for calculating the lower thermosphere neutral density using meteoroid ablation estimated via radar head echos observations. These observations were conducted by making use of ALTAIR, a high power larger aperture radar. We employ a semi-analytical scattering model to correlate a meteor’s head echo return to its plasma density, its mass, and couple this with a continuous single particle ablation model and an optimization technique in order to infer estimates of the surrounding neutral density. We compare our results with the popular MSIS-90 and obtain averaged values 20–40% lower than those computed by the semi-empirical global model. The discrepancies found between our methodology and MSIS-90 are consistent with the differences obtained between in-situ measurements and the semi-empirical global model. In addition, we are capable of observing short term changes in density of a magnitude consistent with experimental results. This suggests that the presented methodology is capable to estimate the thermospheric neutral density. Nonetheless the high error bar associated with our computation, as well as the diversity of the meteoroid flux, and the choice of our ablation model present some limitation to the application of the proposed technique.