Microphysical modeling of a midlatitude "polar stratospheric cloud" event: Comparisons against multiwavelength ground-based and spaceborne lidar data

A high-resolution transport model containing a fully explicit size-resolving microphysical scheme is used to study a large-scale polar stratospheric cloud (PSC) case detected by lidar at midlatitudes between 17 and 23 February 2008. The model simulations, initialized using European Centre for Medium-Range Weather Forecasts (ECMWF) fields and Microwave Limb Sounder (MLS) Aura data, are validated locally against ground-based (Institute for Tropospheric Research Multiwavelength Atmospheric Raman lidar for Temperature, Humidity, and Aerosol profiling (IfT MARTHA)) lidar measurements at Leipzig and globally against spaceborne (Cloud-Aerosol LIdar with Orthogonal Polarization/Cloud-Aerosol-Lidar and Infrared Pathfinder Satellite Observations (CALIOP/CALIPSO)) lidar backscatter measurements. By assuming a 1 K cold bias on the ECMWF temperatures and under the assumption of equilibrated spherical PSC particles, our model produces fields of optical and microphysical parameters like the total surface area density (A) and volume (V). A, and V, as well as the median radius of the PSC size distribution, compare favorably to the corresponding values derived from multiwavelength lidar backscatter measurements. Around 21 km, A and V are found to be around 10 mu m(2) cm(-3) and 1 mu m(3) cm(-3), respectively. The median radius of the Supercooled Ternary Solution particle size distribution is estimated to be around 0.3 mu m using both the model calculations and the lidar-derived size distribution parameters. Overall, despite the simplifications on the microphysical scheme, the model is able to reproduce the salient features of the local and global lidar observations. The results clearly demonstrate the value of CALIOP products for large-scale studies, exploiting chemistry-transport models.