Detection and mapping of polar stratospheric clouds using limb scattering observations

[摘要] Satellite-based measurements of Visible/NIR limb-scattered solarradiation are well suited for the detection and mapping of polarstratospheric clouds (PSCs). This publication describes a methodto detect PCSs from limb scattering observations with the ScanningImaging Absorption spectroMeter for Atmospheric CartograpHY(SCIAMACHY) on the European Space Agency's Envisat spacecraft. Themethod is based on a color-index approach and requires a prioriknowledge of the stratospheric background aerosol loading in orderto avoid false PSC identifications by stratospheric backgroundaerosol. The method is applied to a sample data set including the2003 PSC season in the Southern Hemisphere. The PSCs arecorrelated with coincident UKMO model temperature data, and withvery few exceptions, the detected PSCs occur at temperatures below195–198 K. Monthly averaged PSC descent rates are about 1.5 km/monthfor the −50° S to −75° S latitude rangeand assume a maximum between August and September with a value ofabout 2.5 km/month. The main cause of the PSC descent is theslow descent of the lower stratospheric temperature minimum.

[学科分类] 大气科学