This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
This project aims to make the first airborne observations of polar mesospheric clouds. A campaign is proposed from approximately 25 June to 21 July, coinciding with the period when the occurrence frequency of polar mesospheric clouds is expected to peak. About 25 flights of a Mooney M20K research aircraft will be flown from High Level Airport in Alberta, Canada, at altitudes near 23,000 feet with observations commencing approximately 90 minutes before midnight. The aircraft instrumentation consists of CCD imagers operating at visible and IR wavelengths that will obtain observations over many hours and over an extensive region. Since the aircraft will fly above the tropospheric weather, the imagers will be able to obtain uninterrupted sequential imaging of polar mesospheric clouds over long time periods, providing a unique series of images that will capture the temporal evolution of the clouds. During each flight, the exact overpass time of the Aeronomy of Ice in the Mesosphere (AIM) satellite will be predicted and, if possible, common volume observations will be taken with the airborne imagers and with the downward-looking CIPS camera on AIM. The complementary nature of airborne measurements, providing continuous imaging of polar mesosphere cloud, with satellite measurements, providing extensive polar coverage, would enable the first detailed study of the evolution of the clouds. The timing of the campaign is especially noteworthy in term of the current solar conditions, which features the deepest solar minimum in recent history; an exceptionally cold summer mesosphere is expected. The cloud occurrence frequency is a maximum near the end of solar minimum, during which the clouds often extend to lower latitudes. Some information on the variability of polar mesospheric clouds with season may also be obtained, since the frequency of observation is highly dependent on the day of the season relative to the summer solstice. There are several broader impacts to the project. The research is central to the completion of a student Ph.D. thesis. The coordinated observations made with the NASA AIM satellite will lead to improved delineation of the 2-D polar mesospheric cloud structure and behavior. Polar mesospheric clouds have been hypothesized to be sensitive to global change in the upper atmosphere and the observations obtained would provide a unique complement to the existing cloud database. The project represents a proof-of-concept experiment which may benefit the design and execution of future campaigns.
