Interferometry observations of meteor trail irregularity using the Sanya VHF radar

An experiment of spatial domain interferometry observations of 3-m ionospheric irregularities at a low-latitude location in China was conducted using the Sanya VHF coherent radar. An additional antenna subarray for interferometry was constructed at the geomagnetically north of the main East-West antenna array of the Sanya radar. The main array was used for transmission. Receiving was done using the additional subarray and the main array. By employing the interferometry technique implemented at the Sanya radar, the spatial structure of 3-m irregularities responsible for a long duration range spread trail echo (RSTE) event was reconstructed. It was found that the spatial structure of the RSTE changed its shape from the strip-type elongated along the radar beam's boresight to layer-type in the vertical-meridional plane. Interestingly, the drifts of trail irregularities show a shear related structure above/below the altitude 97 km at which the trail echoes persisted for a long time of ~4 min. Possible causes for the generation and structural evolution of the long duration RSTE are discussed.