We present the first evidence of enhanced irregularity-drift velocities and a velocity shear in the daytime E region at 4.3¿ N dip latitude. These features, found in radar measurements from Kwajalein during q-type sporadic E (Esq) events, are interpreted in terms of a polarization electric field that develops in response to the presence of latitudinal gradients in field-line-integrated conductivity caused by sporadic-E layers. Because the E region over Kwajalein connects directly to 150-km altitude over the magnetic dip equator, we suggest that a similar polarization process is responsible for the so-called 150-km echoes that have been observed routinely by the Jicamarca radar. ¿ American Geophysical Union 1994