- The atmospheric circulation of the extratropical Northern Hemisphere displays several preferred patterns of variability, the most prominent being the Pacific/North American (PNA) pattern. Here we show that a decrease of coral growth at the Flower Garden Banks, Gulf of Mexico, coincides with a decrease in winter air temperature due to the late 1950s shift in the PNA pattern. These results suggest that it may be possible to reconstruct the history of change in the PNA pattern during the last several centuries and examine its relationship to the El Nio/Southern Oscillation phenomenon, the Little Ice Age, and other forms of interdecadal climatic variability. Initial application of this approach suggests that the wintertime phase of the PNA pattern was largely positive from the late 1880s to the first decade of the twentieth century. Copyright 1995 by the American Geophysical Union.