MIPAS observation of polar stratospheric clouds in the Arctic 2002/2003 and Antarctic 2003 winters

Abstract

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) was successfully launched on board ENVISAT in March 2002. The spectrally highly resolved limb emission spectra provide a great opportunity for the detection and differentiation of cloud types. Monitoring of PSC cloud coverage and type differentiation by remote sensors on a vortex-wide basis are essential for better understanding and quantification of the denitrification in both polar vortices and effects on ozone recovery. The MIPAS is currently the only instrument in space delivering global observations of polar stratospheric cloud (PSC) distribution over complete winters. These kinds of measurements are becoming more and more important for the validation of PSC formation mechanisms of microphysical models on a statistical basis. In this study, MIPAS-calibrated limb spectra are analysed. Retrieved PSC quantities (e.g., cloud top heights and PSC occurrence frequencies) for the Arctic winter 2002/2003 and Antarctic winter 2003 are presented in comparison with meteorological analyses. Characteristics of the specific winters are highlighted. In addition, a preliminary PSC type differentiation scheme for nitric acid trihydrate (NAT) particles has been applied to the measured infrared spectra.