October 2002 30‐day incoherent scatter radar experiments at Millstone Hill and Svalbard and simultaneous GUVI/TIMED observations

A long‐duration incoherent scatter radar (ISR) experiment was conducted at Millstone Hill and Svalbard from October 4–November 4, 2002. Along with the simultaneous GUVI/TIMED neutral composition measurements, this 30‐day run enabled us to study a number of thermosphere‐ionosphere‐magnetosphere phenomena. This paper focuses on the day‐to‐day variability and quasiperiodic oscillation of the ionosphere. The day‐to‐day variability under quiet magnetic conditions in electron density Ne, ion temperature Ti and electron temperature Te, respectively, changed with local time and height, with the largest variability in Ne and the smallest in Ti. Midnight through dawn was the period of largest variability. Quasiperiodic Ne oscillations were present with periods >1 day. Some of these oscillations were correlated with changes in the neutral composition originating from geomagnetic activity, which altered the global atmospheric circulation as a result of high latitude heating processes as indicated in Svalbard ion temperature enhancements. However, the wave‐type oscillation of Ne exhibits a downward phase progression which persists up to 600 km and prevails until a large storm appears to impose an upward phase progression.