Comparison between CALIPSO and MIPAS observations of polar stratospheric clouds

Abstract

Polar stratospheric cloud (PSC) detection, top height, and composition as derived from measurements by the infrared emission limb sounder Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) lidar have been compared. The comparisons are based on coincident observations from the 2006 and 2007 Antarctic and the 2006/2007 and 2007/2008 Arctic winters. During the middle of the Antarctic season, very good agreement in common PSC detection (around 90%) has been found. At the beginning and end of the Antarctic PSC season and in the Arctic, the frequency of common PSC detection is generally less (60-70%) which can be explained by cloud inhomogeneity and viewing geometry differences. MIPAS PSC top heights are about 0-2 km lower than CALIPSO top heights with larger offsets at higher altitudes. The negative bias of MIPAS PSC top heights can be modeled under the assumptions of limited horizontal cloud extent and a field-of-view-dependent sensitivity. The comparisons fürther show a high degree of consistency between PSC composition derived from the fundamentally different classification approaches of the two instruments. Remaining differences can be explained considering the physical limitations of each approach and the definition of composition boundaries within the classification scheme of each instrument. Copyright 2009 by the American Geophysical Union.