This proposal sets forth a three-year plan to extend our understanding of the circulation of the Arctic atmosphere during the upcoming Fourth International Polar Year. Specifically, an observational study that combines satellite measurements, lidar measurements, and meteorological soundings and analyses to study the troposphere, stratosphere, and mesosphere will be conducted. The study is an international collaboration between investigators at six institutions in Canada, Germany, Japan and the United States. The satellite observations yield global synoptic-scale temperature measurements of the mesosphere and upper stratosphere while the meteorological soundings and analyses provide global synoptic-scale measurements of the troposphere and lower stratosphere. An international network of four Rayleigh lidars located in observatories at Andoya, Norway (69°N, 16°E), Chatanika, Alaska (65°N, 147°W),  Eureka, Nunavut (80°N, 86°W), and Kangarlussuaq, Greenland (67°N, 51°W), provide a chain of highresolution temperature measurements from the eastern Arctic to the western Arctic. The lidars will yield high-resolution measurements of the structure and circulation of the Arctic stratospheric vortex, the Aleutian anticyclone, the stratospheric surf-zone, planetary waves, tides, and gravity waves that are corroborated by the synoptic-scale satellite and meteorological observations.

Intellectual Merit: The proposed activity will provide a comprehensive analysis of the circulation of the Arctic atmosphere that will directly address the following specific studies; the structure, evolution, and variability of polar vortices and anticyclones, coupling and feedbacks between waves and large-scale circulation, links between the middle and lower atmosphere, atmospheric tele-connections, and modes of variability. This study will provide data and analyses in support of studies of ozone depletion, stratospheric climate, climate oscillations in the Arctic, and long-range horizontal and vertical transport in the Arctic.

We have three specific goals; (i) a study of the Arctic atmosphere that uses observations, modeling and theoretical interpretation to document 3-D structure and evolution of the Arctic vortex and anticyclones with emphasis on vortex-vortex interactions and stratospheric warming/mesospheric cooling events during IPY (ii) to determine our ability to forecast synoptic-scale weather events in the troposphere based on observations and analyses of the mesosphere and stratosphere and (iii) a study of the coupling  between anomalous stratospheric weather and tropospheric annular modes during IPY.

Relevance to IPY: This study addresses all six IPY themes. Using the Arctic as a vantage point, the study will generate benchmark datasets and analyses that will reveal the current state of the polar environment, support studies of climate change, detect and analyze polar-global interactions, investigate new frontiers, and address environmental questions of importance to polar societies. The study is a part of the IPY Expression of Intent PASSMeC (#11) that is a component of two IPY proposals; IPY-SPARC (#196) and IASOA (#217). These proposals been both been endorsed by the IPY Joint Committee. The0 study will also be integrated into the IPY educational and outreach programs.


Broader Impacts: The proposed activity will support education and training of students in science and engineering. The activity will jointly draw on and contribute to research infrastructure in the Arctic, enhance international collaborations, and promote collaboration among observers, modelers and theorists. The research results will be integrated into the University of Alaska and University of Colorado IPY Education and Outreach programs and disseminated through a variety of professional, educational, and outreach programs. The observations, analyses and results of this activity will directly contribute to the CAWSES, CEDAR, SEARCH, SPARC and WAACM programs. The study will support Arctic environmental studies by extending our understanding of coupling between the middle and lower atmosphere. The possibility of improving tropospheric weather forecasts is of high value to the public.