Fig. 2.

Association between Monteverde δ¹⁸O records and regional/global climate. (A) Annual δ¹⁸O cycles are clearly enriched during warm ENSO events (red line; 1905, 1926, 1942, 1952, 1958, 1966, 1969, 1978, 1983, 1987, 1992, and 1998) and extensive WHWP (blue line; 1958, 1969, 1987, 1998) years (20) (A), relative to the overall mean (black line). ± 1σ confidence intervals are shown by same-color shading. (B) The 10 most enriched years in the isotope chronology are associated with an average dry season (January-April) SST anomaly (18) in the eastern Pacific of greater than 1 °C. (C) Similarly, positive dry season (January-April) δ¹⁸O anomalies are associated with weaker 850 mb tradewinds in both the tropical Atlantic and Pacific (19).