Ionospheric variability from the long-duration experiments and the long-term database of the ISR at Millstone Hill

Variability on the daily and monthly basis is a pronounced feature of the upper atmosphere. This presentation addresses two types of the variability as revealed by an ISR. The first is associated with daily variability as observed during ISR long-duration experiments at Millstone Hill. These include results from the last three 30-day continuous operations, conducted with different levels of solar activity and season. The second represents the deviation from climatological conditions obtained with a large database of ISR long-term observations spanning 3 solar cycles at Millstone Hill. We will present patterns of the variability, with emphasis on their height development, in various ISR parameters, i.e., electron density and plasma temperatures. Many dynamical and photochemical processes could contribute to the variability, including, among others, effects of the magnetic activity and forcing from the below. We will look into some of these processes.