Abstract ATM-9510183 Houghton, David D. University of Wisconsin Title: Extratropical Climate Variability in the Coupled Ocean- Atmosphere System This research is focused on understanding and isolating key physical mechanisms related to: 1) the effects of tropical- extratropical interactions on interannual variability in the extratropical North Pacific region, 2) decadal climate variability in the North Pacific, and 3) abrupt shifts in the extratropical atmospheric flow in the transition seasons. Simulations from a hierarchy of numerical models with validation from observations provide the basic data for analysis. Careful diagnostics will enable isolation of specific processes. Such isolation is critical for developing theory and for understanding results from fully coupled models. Observations from global data sets will be used not only for model parameter specification and validation, but also for diagnostic analyses parallel to those that are found useful in the model studies. A strong point for this research project is the close collaboration of scientists representing both the oceanographic and atmospheric science communities. This will enable them to adequately incorporate the key mechanisms of the ocean-atmospheric system important to the various time scales of variability.