Rk. Choudhary et al., FIRST VHF RADAR OBSERVATIONS OF TROPICAL LATITUDE E-REGION FIELD-ALIGNED IRREGULARITIES, Geophysical research letters, 23(25), 1996, pp. 3683-3686
Indian MST radar at Gadanki (13.5 degrees N, 79.2 degrees E, 12.5 degr
ees dip) was operated during July/August 1994, to observe the 3 - m sc
ale size field aligned irregularities associated with the lower E regi
on. Irregularity structure was studied by using height - time variatio
n of the echo intensity and weighted mean Doppler velocity. In this pa
per results of three diurnal cycles of observation are presented. Fiel
d perpendicular echoes were observed both during daytime and nighttime
. A layered irregularity structure extending down to altitude below 86
Km was seen during the nighttime. The daytime structure showed a narr
ow echoing region with significant downward slope. Doppler velocity wa
s in the range of 20 - 50 ms(-1), both during day and night and was, i
n general, consistent with the slope of scattering structure observed
in the height - time - intensity plots.