The investigators will study the morphology and small-scale vertical structure of intense radar echoes from the polar mesopause. Possible generation mechanisms for these unique echoes, called polar mesospheric summer echoes (PMSE), are not well understood, and observations have been limited by the lack of needed resolution. Frequency domain interferometry (FDI) measurements can potentially provide information about the vertical structure of the echoes, but the technique only works when a single layer is present. The investigators have developed a modified approach called Range Imaging (RIM). In this technique, numerous transmitter frequencies are used and sophisticated reconstruction schemes are employed to obtain the desired vertical resolution. The RIM approach will be applied to data obtained from a very high frequency radar in Tromso, Norway. Studying mesospheric chemistry and dynamics is important for understanding the temperature structure of the middle atmosphere. Middle atmosphere temperature is a sensitive indicator of long-term changes associated with global change.
