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In addition to short-term deterministic diagnostic techniques, Williamson and Olson have developed versions of the CAM with very simplified surface conditions, allowing examinations of physical parameterization behavior with both the surface and the large-scale dynamical core. These "aqua-planet" experiments in which the surface is specified to be all ocean with a simple, often zonal, specified sea surface temperature distribution is a useful configuration since the atmosphere retains its full complexity, but eliminated the complexities associated with sea-ice, land, orography, and land-ocean contrasts. This work has led to an internationally coordinated activity known as the Aqua-Planet Experiment (APE) which is being conducted under the auspices of WGNE with collaborators Brian Hoskins and Mike Blackburn (University of Reading), Peter Gleckler (Program for Climate Model Diagnosis and Intercomparison, LLNL) and Richard Neale (NCAR). The project is intended to provide a benchmark of current model behaviors, and more importantly, to stimulate research to understand the cause of differences arising from different models, different subgrid-scale parameterization suites, different dynamical cores, and different methods of coupling parameterized physics and dynamics. In addition to this simplified configuration of CAM, Williamson and Olson have been exploring methods for evaluating the quality of dynamical approximations in global models. While most model development groups devise and apply tests during their model development and model documentation, the tests themselves are often not specified in enough detail that another group can completely reproduce the setup or analysis for comparison. To date there is no commonly adopted set of tests with specified metrics for baroclinic cores such as the set commonly used with the shallow water equations. Jablonoski proposed one easy to apply test involving the growth of a specified perturbation in a baroclinicly unstable flow. Jablonoski and Williamson (2006) studied the convergence-with-resolution characteristics four very different dynamical cores, three of which are options in the CAM, and evaluated the uncertainty of the high resolution reference solutions produced by the cores. They continue to develop and evaluate baroclinic core test cases which have potential to become standard approaches for testing new dynamical approximations.