This proposal directly addresses key questions related to understanding how the Earth�s atmosphere is changing and how those changes affect life on Earth. We propose tasks designed to improve our understanding of polar stratospheric clouds (PSCs) and stratospheric aerosol. CALIPSO multi-wavelength backscatter measurements are uniquely capable of addressing trends and variations of these key components of ozone change and climate variations. Specifically, we will assess the CALIPSO PSC detection capability and develop an algorithm for the identification and microphysical classification of PSCs. This work will bridge existing gaps in our understanding of PSCs and their chemical effects, particularly in the areas of solid particle formation and their denitrification potential, and will provide a more comprehensive picture of the clouds than attainable with previous satellite instruments. We will also assess the CALIPSO capability to measure stratospheric aerosol and develop a stratospheric aerosol product. While challenging, these measurements may provide a detailed depiction of the stratospheric aerosol during a period when few other space-based instruments will measure aerosol in the stratosphere. This data could provide important insight into the role of human-derived aerosol in the tropical upper troposphere/lower stratosphere. We will apply the PSC and stratospheric aerosol algorithms to CALIPSO data and archive the results as CALIPSO data products.
