Abstract
Data on monthly sea surface temperatures (SST) over the eastern North Pacific as well as surface pressure and 1000–500 mb layer thickness over North America during the period 1960–73 were analyzed. Factor analysis of the SST data, used to find areal patterns of anomalous SST in the ocean, revealed that while three large regions dominated the eastern North Pacific from 1960 to 1970 there was a change, possibly during 1971, resulting in the predominance of a new region called the southwestern oceanic region. At nearly the same time there was noted a reversal in the tendency toward abnormally cold winters throughout the eastern United States.
Fluctuations in pressure and thickness over North America associated with anomalous periods of warm and cold water in the original three SST cells were then analyzed. The east-central North Pacific and Gulf of Alaska regions were found to be associated with statistically significant fluctuations in pressure near the Gulf of Alaska and in thickness over west-central Canada. The southeastern oceanic region was associated with statistically significant fluctuations in pressure near the Pacific anticyclone and in thickness over a large area centered on the Arctic archipelago.
