FY 1986

The Equatorial Pacific Ocean Climate Studies (EPOCS) Plans: 1986–1988

Hayes, S.P., D.W. Behringer, M. Blackmon, D.V. Hansen, N.-C. Lau, A. Leetmaa, S.G.H. Philander, E.J. Pitcher, C.S. Ramage, E.M. Rasmusson, E.S. Sarachik, and B.A. Taft

Eos Trans. AGU, 67(18), 442–444, doi: 10.1029/EO067i018p00442 (1986)

The Equatorial Pacific Ocean Climate Studies (EPOCS) Project of the National Oceanic and Atmospheric Administration (NOAA) Environmental Research Laboratories was initiated in 1979 to investigate the role of the tropical Pacific Ocean in influencing large-scale interannual climate fluctuations. The principal hypothesis of EPOCS is that interannual variability of sea surface temperature (SST) in the equatorial Pacific Ocean is intimately related to atmospheric fluctuations associated with the Southern Oscillation. This hypothesis is supported by numerous empirical and theoretical studies. The coupled ocean-atmosphere signal has become known as the ENSO (El Niño-Southern Oscillation) phenomenon, and it is recognized as one of the principal modes of global interannual climate change. This recognition and the increased scientific interest in ENSO problems has led to the formulation of the international Tropical Ocean Global Atmosphere (TOGA) Program, which is being coordinated by the World Climate Research Program (WCRP) of the World Meteorological Organization (WMO) and the International Council of Scientific Unions (ICSU). EPOCS is a contribution to the U.S. TOGA effort. The goal of the EPOCS program is an improved understanding of ENSO phenomena, leading to the development of the capability to simulate the tropical Pacific Ocean and atmosphere conditions in near-real time and to predict various aspects of the evolution of these conditions. The ENSO phenomena reflect large-scale interactions between ocean and atmosphere systems. To understand these interactions, it is necessary to diagnose the coupled system. However, since the phenomena are inadequately described at present, and since knowledge of the dominant physical process is so incomplete, a totally integrated approach to all aspects of the problem is impractical. Progress has been made by separately considering the effects of SST anomalies on the atmosphere and the effects of wind and surface heating perturbations on the ocean. Much research remains to be done in these areas, and to a large extent, EPOCS can be divided into coordinated ocean and atmosphere components. The accomplishments and plans for the integrated program are presented in the report "Equatorial Pacific Ocean Climate Studies: Progress and Plans" (EPOCS, 1986). In this article, we present an overview of the meteorological and oceanographic plans.