Global general circulation models are the standard tool used to diagnose climate processes and interactions and to project future climate changes. ITPA faculty members are pursuing research to understand and improve these models. A major limitations of the models is that the grid size is large compared to the distance-scales important to processes related to topography, clouds and vegetation. A major challenge in climate modeling is to find simple but realistic parameterizations of sub-grid scale processes, and this is one of the components of research being pursued in ITPA. Another is to gauge the significance of climate change impacts in the 21st century as simulated by global climate models. A particular focus is on storms, the changes taking place in winter storm tracks and their impact on regional climate on the east coast of North America, as well changes in the number and intensity of tropical storm and hurricanes. New York City and Long Island are vulnerable to coastal flooding. Our faculty has combined regional atmospheric models and ocean models to estimate wave heights and storm surges in these areas expected from storms of varying intensities.