Lidar observation of spherical particles in a -65°cold cirrus observed above Sodankyla (Finland) during S.E.S.A.M.E.
The absence of LIDAR depolarization in a polar cirrus observed above Sodankyla (Finland) showed the presence of spherical particles at -65°C. The presence of pure liquid water is excluded, since homogeneous freezing should occur at or above -40°C. The cirrus layer was detected at the tropopause, during the horizontal and vertical advection above northern Scandinavia of warm and wet oceanic air. Tw
