Structure and evolution of the polar stratosphere and mesosphere and links to the troposphere during the International Polar Year, 2007-2009 (SPARC IPY)

The goal of SPARC IPY is to document the dynamics, chemistry and microphysical processes within the polar vortices during IPY, with a focus on stratosphere-troposphere and stratosphere-mesosphere coupling. A key outcome will be a collection of analysis products from several operational centres and several research centres, which will be archived at the Polar Data Catalogue and the SPARC Data Center. The analysis products will represent the best available self-consistent approximations to the state of the atmosphere during this period. SPARC IPY is linked with several International IPY activities: POLARCAT (Activity 32, which has been endorsed by SPARC), ORACLE-O3 (Activity 99), PANSY (Activity 9), and IASOA (Activity 196). The Canadian SPARC model outputs were shared with IPY-TAWEPI (CCIN#11399). The evolution of stratospheric ozone and other important and related atmospheric constituents in polar regions is tightly coupled to a wide range of processes acting within and outside the winter polar vortices and through the entire atmosphere from the surface to the mesopause. Much of the current understanding of these processes has been achieved within the programme of SPARC (Stratospheric Processes And their Role in Climate), a WCRP (World Climate Research Programme) core project, and other international projects with which it maintains collaborative links. IPY offers a unique opportunity for SPARC to assemble a range of scientific expertise to study the Antarctic and Arctic polar vortices, the loci of key chemical and physical processes associated with ozone depletion and its eventual recovery, as well as of key features of the dynamical coupling between the troposphere, stratosphere, and mesosphere in polar and sub-polar regions. The central goal of SPARC IPY is to document as completely as possible the dynamics and chemistry of the polar vortices and physical properties relevant to processes such as the formation of polar stratospheric clouds. To achieve this detailed picture and yield a unique synthesis of data on the polar middle atmosphere, SPARC IPY will facilitate analysis of available research and operational satellite data, as well as ground-based and aircraft data, and encourage work on data assimilation and inter-comparison of assimilated data sets.