Preliminary results from joint measurements of E-region field-aligned irregularities using the MU radar and the frequency-agile radar

In the period from 26 May to 26 July 1993, we have conducted a joint experiment of field-aligned irregularities (FAI) in the mid-latitude E-region by using the MU radar (MUR) and the Frequency-Agile radar (FAR). While the MUR in Shigaraki was utilized to conduct multi-beam observations of FAI, the FAR was operated in Taga, which is approximately 40 km north of the MUR site, to reveal the horizontal structure of the FAI echoes. The simultaneous observations with both radars were successful for 17 days. The multi-beam experiments with the MUR showed that the quasi-periodic' echoes had a monochromatic wave structure propagating westward. Moreover, the comparison of echoing regions between both radars showed that the wavefront of the FAI echoes aligned from northwest to southeast, and propagated toward southwest or west-southwest. The full-correlation technique was applied to crosscorrelation functions between echo intensities from both radars to give an averaged motion of the FAI echoing regions, which showed similar results to the one-by-one comparison of the FAI echoing regions. (C) 1997 Elsevier Science Ltd.