Despite significant progress in the Tropical Ocean—Global Atmosphere (TOGA) program, a number of major hurdles remain before the primary objective, prediction of the variability of the coupled ocean—atmosphere system on time scales of months to years, can be achieved. Foremost among these hurdles is understanding the physics that maintains and perturbs the western Pacific warm pool, the region of the warmest sea surface temperature in the open oceans, which coexists with the largest annual precipitation and latent heat release in the atmosphere. Even though it is believed that the warm pool is a “center of action” for the El Niño—Southem Oscillation (ENSO) phenomena in the ocean and the atmosphere, successful simulation of the warm pool has remained an elusive goal. To gain a clear understanding of global climate change, the ENSO phenomenon, and the intraseasonal variability of the coupled atmosphere—ocean system, it is clear that a better specification of the coupling of the ocean and the atmosp... Abstract Despite significant progress in the Tropical Ocean—Global Atmosphere (TOGA) program, a number of major hurdles remain before the primary objective, prediction of the variability of the coupled ocean—atmosphere system on time scales of months to years, can be achieved. Foremost among these hurdles is understanding the physics that maintains and perturbs the western Pacific warm pool, the region of the warmest sea surface temperature in the open oceans, which coexists with the largest annual precipitation and latent heat release in the atmosphere. Even though it is believed that the warm pool is a “center of action” for the El Niño—Southem Oscillation (ENSO) phenomena in the ocean and the atmosphere, successful simulation of the warm pool has remained an elusive goal. To gain a clear understanding of global climate change, the ENSO phenomenon, and the intraseasonal variability of the coupled atmosphere—ocean system, it is clear that a better specification of the coupling of the ocean and the atmosp...