Real-time Determination of F-region Critical Frequencies Using SuperDARN

In addition to detecting backscatter from ionospheric field-aligned irregularities, SuperDARN radars are sensitive to ground scatter returns. The profiles of these returns vary in a systematic manner with frequency and can be used to determine HF propagation characteristics and ionospheric critical frequencies. The large spatial coverage and good time resolution provided by the SuperDARN network make it possible to produce maps of high-latitude critical frequencies approximately every 15 minutes. Recent upgrades to the SuperDARN operating software provide the capability to receive the ground scatter profiles and angle of arrival information in real-time via the internet and we use these data to construct near real-time maps of F-region critical frequencies. In this paper, the technique will be described and representative data will be discussed.