Continuous quasiperiodic thermospheric waves over Arecibo

Abstract

Incoherent scatter radar (ISR) power profile observations at Arecibo Observatory (AO) have revealed long vertical wavelength (>100 km) quasi‐coherent waves with periods of ∼1 hour that are observed to be nearly continuously present over two ∼35‐hour geomagnetically quiet observation periods. When properly filtered, results from both 22–23 March 2004 and 5–6 June 2005 provide unambiguous views of these waves. The waves are strong throughout the F region, often spanning 160 to above 500 km in altitude and are present day and night in the F2 layer. Filtering techniques that were used to better reveal the waves are extensively discussed. Barometric pressure and imager data, both of which were taken on site at Arecibo, are used to provide further insight into the nature of these waves. These waves may be linked to high‐latitude medium‐scale traveling ionospheric disturbances (MSTIDs) observed with the superDARN radar network and associated with E region auroral electrojet source(s) that are quasi‐coherent under geomagnetic quiet conditions. As auroral‐zone MSTIDs are believed to dissipate before reaching Arecibo latitudes (Vadas, 2007), various alternative sources including weather patterns are explored.