Radar investigations of low‐altitude quasi‐periodic echoes in Chung‐Li

[1] Quasi-periodic (QP) radar echoes from the sporadic E-layers are also found at altitudes below 100 km which we call Low-altitude Quasi-Periodic echoes (LQP). We have used the Chung-Li VHF radar to study correct locations of these echoes creating irregularities, which are confined to the height range between 90 km and 100 km, have a thickness of 2–4 km and are only slowly descending in altitude. They occur with periods of some tens of seconds to maximum three minutes. Since Chung-Li is close to the equatorial region, we can prove that these LQP occur in this temperate region as well. The particular progress reported here is that interferometry allows us to determine the position of the scattering irregularities in three dimensions, which provides new information about the motion of the scatterers. We concur with the assumption that the LQP echoes are created in a strong wind shear below 100 km altitude.