VHF doppler radar backscatter measurements through the entire neutral atmosphere (15-95 km) above Jicamarca, Peru

Abstract

The Jicamarca 50-MHz radar was used to obtain backscattered echoes through the entire atmosphere (0-100 km). Previous radar observations at VHF have shown a gap near the 35-55 km region, where the lack of echoes is attributed to a lack of radar sensitivity. By using the full Jicamarca antenna array and maximun transmitter power and by optimizing transmitter duty cycle through the implementation of complementary codes, doppler measurements display discernable peaks in the computed spectra from atmospheric signals in the gap region as well as above and below it. The results indicate that a minimum power-aperture threshold in excess of 1010 W-m2 is required in order to obtain backscatter echoes near 50 MHz through the entire neutral atmosphere.