Frequency Dependence of Radar Meteor Echo Rates

Meteor rates have been measured with a large HF Radar at a number of frequencies. At the top end of the HF band our results match those of Greenhow (1963). However at lower frequencies we find high echo rates which indicate that past observations measured only a few percent of the total meteor flux incident on the Earth’s atmosphere. This explains the ‘missing mass’ discrepancy observed when radar results are compared with satellite or visual data. Accounting for’this missing mass results in a four-fold increase in the calculated total meteoroid mass influx to the surface of the Earth from 4000 to 16,000 tonnes per year. Our results also imply that the majority of echoes originate from altitudes above 100 km.