This award will support the postdoctoral research of Dr. Jorge Chau at the Jicamarca Radio Observatory in Peru. The research has two parts: (1) the study of the east-west symmetry in 50 MHz radar echoes from the equatorial electrojet, and (2) the study of meridional variations in the E-region irregularities. For the first task, the investigators will examine whether or not the penetration of gravity wave energy associated with the nearby Andean Cordillera may play a role in sustaining the observed asymmetry in the radar echoes. For the second task, the investigators will use simultaneous measurements made with the Jicamarca radar and a 50 MHz wind profiler radar in Piura, Peru, about 1000 km north of Jicamarca. The researchers will look for possible differences in nighttime echoes in Piura related to the presence or absence of spread F over Jicamarca at magnetically connected locations in the ionosphere.