Analysis of ALTAIR 1998 meteor radar data

Abstract

We describe a new analysis of a set of 32 UHF meteor radar traces recorded with the 422 MHz Advanced Research Project Agency Long-Range Tracking and Identification Radar facility in November 1998. Emphasis is on the absolute velocity measurements and inferences that can be drawn from them regarding the meteoroid masses and mass densities. We find that the 3-D velocity versus altitude data can be fitted as quadratic functions of the path integrals of the atmospheric densities versus distance, and deceleration rates derived from those fits all show the expected behavior of increasing with decreasing altitude. We also describe a computer model of the coupled processes of collisional heating, radiative cooling, evaporative cooling and ablation, and deceleration for meteoroids composed of defined mixtures of mineral constituents. For each of the cases in the data set, we ran the model starting with the measured initial velocity and trajectory inclination and with various trial values of the quantity mρs2 (initial mass times mass density squared) and then compared the computed deceleration versus altitude curves versus the measured ones. In this way we arrived at the best fit values of the mρs2 for each of the measured traces. Then further, assuming various trial values of the density ρs, we compared the computed mass versus altitude curves with similar curves for the same set of meteoroids determined previously from the measured radar cross sections and an electrostatic scattering model. In this way we arrived at estimates of the best fit mass densities ρs for each of the cases. Copyright 2011 by the American Geophysical Union.