Evidence of response to external perturbations in nine years of lidar observed nightly mean temperatures in a midlatitude mesopause region

A new narrowband sodium lidar for measuring temperature and sodium density was implemented at the Christman Field of Colorado State University in 1989 and regular observations of temperatures in the mesopause region over Fort Collins, CO (40N, 105W) have been made since 1991, averaging 4 to 5 nights a month. Analysis of the time series of the nightly mean temperatures covering a nine-year span, revealed an episodic warming attributable to Mount Pinatubo eruption, along with evidence of background temperature changes in response to solar flux variability.