An analysis of mountain polar stratospheric cloud observations by solar absorption FTIR from Kiruna/Sweden was performed and compared with co-located air-borne lidar measurements. The infrared cloud spectral signature and optical depth indicated water ice particles compatible with the high backscatter and depolarization ratio of the lidar signal. Retrieval of mean particle properties from the FTIR spectrum depend on the assumed width of the particle size distribution and range from 2.0 to 1.1 &mgr;m radius and from 1.9 to 5.1 cm-3 number density. The volume density is well determined with 63.8--60.2 &mgr;m3/cm3 equivalent to about 2.5 ppmv of condensed water at 20 hPa. Simulations of lidar backscatter ratio based on these results are consistent with the lidar observations. ¿ 2001 American Geophysical Union