1. CEDAR Frontiers: Effects of stratospheric warming in the mesosphere/thermosphere L. Goncharenko, MIT Haystack Observatory I. Azeem, Embry-Riddle Aeronautical University The sudden stratospheric warming is a dramatic feature of the winter atmosphere which causes significant variations in winds and temperatures. The sudden stratospheric warming is a dramatic feature of the winter atmosphere which causes significant variations in winds and temperatures. Recent observations have extended studies of effects related to stratospheric warming to mesosphere and lower thermosphere and showed (Hoffman et al., 2002, JASTP, Dowdy et al., GRL, 2004, Azeem et al., 2005) : Recent observations have extended studies of effects related to stratospheric warming to mesosphere and lower thermosphere and showed (Hoffman et al., 2002, JASTP, Dowdy et al., GRL, 2004, Azeem et al., 2005) : Mesospheric cooling prior to stratospheric warmingMesospheric cooling prior to stratospheric warming MLT zonal wind reversal prior to the stratospheric warmingMLT zonal wind reversal prior to the stratospheric warming The response of mesosphere to stratospheric warmings depends on a number of factors which are not yet completely understood. The response of mesosphere to stratospheric warmings depends on a number of factors which are not yet completely understood.

2. Stratospheric warming and thermosphere The response of lower thermosphere (>100km) to stratospheric warming events is not known. The response of lower thermosphere (>100km) to stratospheric warming events is not known. Wintertime winds and temperatures in the lower thermosphere are much more variable than during other seasons (Goncharenko and Salah, JGR, 1998). Wintertime winds and temperatures in the lower thermosphere are much more variable than during other seasons (Goncharenko and Salah, JGR, 1998). Tidal signatures before major stratospheric warming (LTCS-6, Dec 1991) were vastly different from other winter campaigns. Tidal signatures before major stratospheric warming (LTCS-6, Dec 1991) were vastly different from other winter campaigns. Pronounced and persistent variability for this period was also reported in thermospheric parameters in the F-region (Hagan and Salah, JGR, 1995). Pronounced and persistent variability for this period was also reported in thermospheric parameters in the F-region (Hagan and Salah, JGR, 1995). From Goncharenko and Salah, JGR, 1998

3. ISR 2007 World Day proposal Key objectives: Key objectives: To extend studies of stratospheric warming effects to the lower thermosphere and investigate possible coupling with the ionosphereTo extend studies of stratospheric warming effects to the lower thermosphere and investigate possible coupling with the ionosphere To examine the mechanisms responsible for variations in lower thermospheric dynamics and temperatures and investigate to what degree they can be related to sudden stratospheric warming.To examine the mechanisms responsible for variations in lower thermospheric dynamics and temperatures and investigate to what degree they can be related to sudden stratospheric warming. To compare variations in temperatures and winds to mesospheric response as given by ground-based instruments (MF radars, meteor radars, lidars) and space-based instruments (TIMED -SABER, TIDI, GUVI).To compare variations in temperatures and winds to mesospheric response as given by ground-based instruments (MF radars, meteor radars, lidars) and space-based instruments (TIMED -SABER, TIDI, GUVI).