Eastern Pacific sea surface temperature since 1600 A.D.: The δ18O record of climate variability in Galápagos Corals

摘要: We measured stable oxygen isotope ratios and skeletal growth rates in the massive corals Pavona clavus P. gigantea from west coast of Isabela Island, Galapagos, to assess interannual decadal climate variability eastern Pacific. Comparisons instrumental data sets show that sea surface temperatures (SST) Galapagos region are representative a broad portion equatorial The site is especially well-suited for long-term studies El Nino/Southern Oscillation (ENSO) phenomenon, as it lies within Pacific “center action” thermal anomalies associated with ENSO. record nearly monthly resolution, spans period 1961–1982, shows strong correlation SST (r = −0.90 annual averages). Cross-spectral analysis can explain greater than 80% variance δ18O at both cycle high-frequency ENSO band (3-5 years). extends 1587 1953 A.D., was obtained 10-m diameter colony preserved Urvina Bay uplift. Because seawater variations very small, we interpret coral terms average SST. isotopic appears be good, but not perfect, indicator events good correspondence historical reconstruction Quinn et al. (1987). A number low excursions observe during 17th 18th centuries likely represent missing tabulations. Most between 1607 A.D. temperature 1° 2.5°C. During Little Ice Age, series correlates well many North American tree ring records early 1600s 1800s, relatively warmer conditions 1700s. Unlike most northern hemisphere records, see no evidence this warming 1880 1940 rather slight cooling ( 28% total variance. main mode centered 4.6 years accounts 12% Additional significant oscillations occur periods 3.3, 6, 8, 11, 17, 22, 34 years. Both rate equivalent solar magnetic (e.g., 11 22 years, respectively). In addition, amplitude 11-year generally varies cycle, supporting previous suggestions may modulate tropics. dominant oscillatory modes, interdecadal frequency bands, shift shorter middle 1700s again late 1800s. This reflect major reorganizations tropical ocean-atmosphere system suggests linked across timescales ranging decades.