The earth's climate has varied significantly in the past, yet climate records revealthat in the tropics, sea surface temperatures seem to have been remarkably stable, varying by less than a few degrees Celsius over geologic time. Today, the large "warm pool" of the western Pacific shows similar characteristics. Its surface temperature always exceeds 27ºC but never 31ºC. Heightened interest in this is observation has been stimulated by questions of global climate change and the exploration of stabilizing climate feedback processes. Efforts to understand the observed weak sensitivity of tropical sea surface temperatures to climate forcing has led to a number of competing ideas about the nature of this apparent thermostat. Scientists are actively debating these ideas, as evidenced by the recent number of papers and correspondence on the subject. Although there remains disagreement on the processes that regulate tropical sea surface temperature, most scientists agree that further progress in resolving these differences requires comprehensive field observations of three-dimensional water-vapor concentrations, solar and infrared radiative fluxes, surface fluxes of heat and water vapor, and cloud microphysical properties. This document describes the Central Equatorial Pacific Experiment (CEPEX) plan to collect such observations over the central equatorial Pacific Ocean during March 1993. When combined with the field observations being collected between November 1992 and February 1993 in the western Pacific by the Coupled Ocean- Atmosphere Response Experiment (COARE) and the normally available background data from ocean buoys, national weather services, and satellites, this special tropical Pacific data set will provide researchers with an unprecedented observational resource for investigating how tropical sea surface temperature is regulated.
Chairman, CEPEX Scientific Steering Committee