Overview

The Eastern Tropical Pacific is characterized by anomalous sea surface temperatures which perturb the atmosphere and alter weather and climate in remote locations, including North and South America. It is believed that the remarkably persistent stratus decks to the west of Peru and Chile (Figure 1) exert a strong cooling influence on the local and global heat balance and, further, that they play a role in maintaining the equatorial asymmetry of Sea Surface Temperatures and winds in the eastern Pacific. However, our understanding of the processes that control ocean sea surface temperature in this region is lacking due to the sparse and incomplete observations there.

The Stratus project was conceived in order to monitor the evolution and coupling of the oceanic and atmospheric boundary layers under the persistent stratus cloud deck found west of Peru and Chile (Figure 2). This project embedded within the Eastern Pacific Investigation of Climate (EPIC ) program began in October 2000 and will contribute, over a several annual cycles, to our understanding of the role of clouds in the eastern pacific in modulating atmosphere-ocean coupling.

Figure 1: Eastern tropical Pacific, showing climatological stratus cloud (gray), rain (orange), and surface winds for March-April (left) and September-October (right). The position of the buoy is marked by a red square.

A well-instrumented surface mooring had deployed and recovered at 20'S, 85'W once in October 2001 by the Upper Ocean Processes group (UOP) of the Woods Hole Oceanographic Institution (WHOI) in order to collect accurate time series of surface meteorology and upper ocean temperatures, velocities, and salinities.The data collected from the mooring will improve our understanding of the air-sea fluxes in the eastern tropical Pacific and be used to examine the processes that control sea surface temperature there.

Figure 2: Stratus Mooring Location