Climate Change in the Upper Atmosphere

This project will explore climate change in the upper atmosphere, based on long-term incoherent scatter radar (ISR) observations of the ionosphere. This study used ion temperature (Ti) data which gives a direct measurement of the upper atmosphere thermal status since it is very close to the neutral thermosphere temperature (Tn) from 100 km up the F2 peak region. Preliminary studies targeting the altitude region between 350-400 km above the Millstone Hill Incoherent Scatter Radar shows a clear decreasing trend in Ti which agrees with theoretical calculations for the greenhouse effect. This project will provide a height profile of the trend from the lower (E-region) to the higher (F-region) part of the ionosphere, and will in addition to the Millstone Hill radar use data from another mid-latitude site (St. Santin). Sondrestrom and Chatanika/Poker Flat, both at high latitudes, will also be utilized to demonstrate the geographic extent of the trends, and to provide insight into the origin of the climate change in the upper atmosphere.