Finally, it was envisioned that one or more process studies would be required for significant improvement of model parameterizations of key physical processes, such as upper-ocean mixing, atmospheric turbulence and convection, and interactions between clouds and radiation. Process studies would also permit sorting out of the relative importance of the myriad atmospheric and oceanic phenomena with similar or shorter time scales that might play a role in altering the behavior of coupled modes of seasonal-to-interannual variation. The drafters of the original science plan (NRC 1983) could not determine the optimal location for the process experiment(s)—eastern, central, or western Pacific—and therefore recommended a separate experiment for each. As it turned out, an experiment was performed in each of these regions. The major process study during TOGA, COARE, was performed in the western Pacific, the region thought to be most important for the development of ENSO.