Mountain polar stratospheric cloud measurements by ground based FTIR solarabsorption spectroscopy

An analysis of mountain polar stratospheric cloud observations by solar abs orption FTIR from Kiruma/ Sweden was performed and compared with co-located airborne lidar measurements. The infrared cloud spectral sig nature and op tical depth indicated water ice particles compatible with the high backscat ter and depolarization ratio of the lidar signal. Retrieval of mean particl e properties from the FTIR spectrum depend on the assumed width of the par tide size distribution and range from 2.0 to 1.1 mum radius and from 1.9 to 5.1 cm(-3) number density. The volume density is well determined with 63.8 -60.2 mum(3)/cm(3) equivalent to about 2.5 ppmv of condensed water at 20 hP a. Simulations of lidar backscatter ratio based on these results are consis tent with the lidar observations.