Relation between Equatorial Ionospheric Scintillations and Atmospheric Waves from Below

Abstract

This paper reviews some results from equatorial GPS ionospheric scintillation observations that have been conducted at Kototabang, Indonesia since January 2003, and briefly discusses relations between scintillation and atmospheric waves from below. GPS scintillations caused by plasma bubbles appeared between 2000 and 0100 LT mainly in equinotial months, and their activity decreased with decreasing solar activity. The scintillation activity can be related to tropospheric disturbances over the Indian Ocean to the west of Kototabang. Scintllation index fluctuates with periods of planetary waves, and similar periods are also found in Earth's brightness temperature variations. Numerical simulations to know behavior of neutral wind in the equatorial thermosphere indicate that planetary waves dissipate rapidly above about 125 km, and short-period atmospheric waves become predominant above 100 km. It is suggested that these atmospheric waves can contribute to the generation of plasma bubbles causing the scintillations.