The Impact of the Stratosphere on Arctic Climate

DESCRIPTION: The Arctic surface climate has warmed dramatically over the past several decades. This warming, known as Arctic amplification, is associated, most notably, with extensive loss of sea ice. The Arctic stratosphere has also been experiencing change, including significant stratospheric ozone depletion. There is increasing evidence that polar stratospheric variability and change can have a significant downward impact on the surface climate. The proposed research will examine the connection between stratospheric circulation and chemistry and past and future changes in the surface climate of the Arctic region. Understanding the coupling between the stratosphere and the surface in the Arctic region has potentially important implications for sea ice and weather forecasting. In addition, the proposed research will lead to an improved understanding of the local and remote processes that will determine Arctic stratospheric and tropospheric ozone concentrations in the future. This is important because (a) stratospheric ozone protects the earth from harmful ultraviolet radiation and (b) tropospheric ozone is a toxic pollutant, which may have potential negative impacts on air quality and vegetation in the region. This project will contribute to STEM workforce development in two ways. The principal investigator is a beginning investigator and this project will provide her support during the formative years of her career. The project will also provide support for the training of a graduate student. The anticipated science results have the potential to contribute to improve short-range forecast of sea ice and weather. The project will enhance collaboration between NCAR and Columbia University. Outreach to high school students will be enabled through leveraging of programs at the American Museum of Natural History and in the Inuit village of Arviat. Finally, research results will be shared with local K-12 teachers through an ongoing program sponsored by the principal investigator?s home institution.  The proposed research will be carried out by employing both observationally-based data products and global climate model integrations to address the question of whether stratospheric circulation and chemistry has a downward influence of the Arctic surface climate, particularly sea ice, on seasonal, interannual and multi-decadal time scales. From a modeling perspective, the approach outlined in the proposal will be to employ the Whole Atmosphere Community Climate Model (WACCM), with three different configurations that will allow examination of the interplay between dynamics and chemistry: (i) the standard WACCM with interactive stratospheric chemistry, (ii) the specified-chemistry version of WACCM (SC-WACCM) and (iii) the new fully coupled WACCM-TSMLT with tropospheric and stratospheric chemistry.