Past Air-sea Interactions Over the Eastern North Pacific Ocean as Revealed by Tree-Ring Data

Abstract

Analyses are made of sea surface temperature (SST) data and tree-ring data from Southern California. Multiple linear regression analyses of the two sets of data indicate that SST data for Port Heuneme, Balboa, and La Jolla can be reconstructed using tree-ring data from five tree-ring sites in Southern California. Prediction equations were obtained from the analyses, and 23% to 63% of the year-to-year variance in seasonal SST were explained, with the highest percentages for the spring and summer equations. The reconstructed SST data are believed to be a conservative estimate of past SST anomalies, but independent data suggest the predictions are qualitatively accurate. An analysis was made of possible air-sea interactions using the reconstructed SST data which begin in 1611. The reconstructed SST data suggest that at times during the decades of 1610,1680, 1770, 1830, and 1850, sea surface temperatures may have been 20 C or 30 C warmer than the present averages. At times during the decades of 1640, 1710, and 1880, sea surface temperatures may have been 20 C or 30 cooler than the present averages. An analysis presented indicates that these reconstructed SST data for coastal Southern California may reflective of broad scale SST anomalies in the eastern North Pacific, and thus, the uses of the reconstructed data need not be limited to local problems along the coast of Southern California.