Micronesia

Vertical cores were retrieved from Porites corals at Chuuk Atoll (8°N, 152°E) and Pohnpei Island (7°N, 158°E) of the Federated States of Micronesia (Fig. 1). A 180-cm-long coral core was extracted on March 11-12, 1999 from a Porites

Figure 2: (A) Map of correlations of the smoothed Southern Oscillation Index (SOI; negative Darwin sea-level pressure anomalies) with monthly SST anomalies from 1950 to 1994 (contour interval, 0.1). Magnitudes of regression coefficient (R) exceeding +0.7 and —0.7 are lightly and darkly shaded, respectively. The map is reproduced from Trenberth and Hoar (1996). (B) Pattern of annual precipitation anomalies associated with moderate to strong El Nino events from 1900 to 1998 compared to normal years (after Dai and Wigley, 2000). Locations of sites with coral records discussed in text are shown by circles.

Figure 2: (A) Map of correlations of the smoothed Southern Oscillation Index (SOI; negative Darwin sea-level pressure anomalies) with monthly SST anomalies from 1950 to 1994 (contour interval, 0.1). Magnitudes of regression coefficient (R) exceeding +0.7 and —0.7 are lightly and darkly shaded, respectively. The map is reproduced from Trenberth and Hoar (1996). (B) Pattern of annual precipitation anomalies associated with moderate to strong El Nino events from 1900 to 1998 compared to normal years (after Dai and Wigley, 2000). Locations of sites with coral records discussed in text are shown by circles.

lutea colony at 3.9 m below mean sea level (MSL) in a channel of the outer reef near the Northeast Pass, Chuuk Atoll. The core (sample ID: CHU99-01) was sectioned into 7-mm-thick slabs, which were cleaned with deionized water.

Coral slabs were processed according to the microsampling procedures described by Gagan et al. (1994, 1996, 1998). The microsampling interval was 400 mm along the major growth axis of the core. Measurements of skeletal oxygen isotope ratio (S18Oc) were carried out on every fourth sample over a distance of about 17 cm downward from the growth surface of the colony, corresponding to a time resolution of about 1 month.

A 97-cm-long coral core (sample ID: POH99-02) was recovered from a Porites sp. colony at about 1.0 m below MSL on the coral reef about 2 km offshore of the airport near Kolonia, Pohnpei Island, on March 15, 1999 (Inoue et al., 2004). The same procedures were employed to microsample this core. We also obtained cores from a Porites sp. coral in Majuro Atoll's lagoon in 1999, but here we only discuss the result of SST monitoring at Central Shoal, also in the lagoon.

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