First observations of equatorial spread F from Indian MST radar

Abstract

The newly established MST radar at Gadanki (13.5° N, 79.2° E) was operated on a few occasions in ionospheric field-aligned backscatter mode to investigate the small-scale (˜3 m) irregularities associated with the equatorial spread F. Observations are presented of sample Doppler spectra and height-time variations of signal intensity and weighted mean Doppler velocity. The Doppler spectra are mostly of the composite type similar to that observed at Jicamarca and are quite variable both in height and time. The Doppler velocities of the 3-m irregularities are found to be consistent in general with the slopes observed of the scattering structures in the height-time-intensity plots. The peak signal intensities are found to be as high as 40 dB above the mean noise level, and the peak Doppler velocities are around 70 m s^-1.