Eastern Pacific Climate Variability Reconstructed from Porites Coral Geochemical Tracers over the Last Millennium

Abstract:

The tropical Pacific is under the influence of different climate modes (from the seasonal to the

decadal timescale) and, through teleconnections, affects the global climate. The tropical

Pacific is also subject to strong and variable zonal sea surface temperature (SST) gradients at

the interannual timescale (El Niño Southern Oscillation phenomenon: ENSO). A large

amount of climate records are available in the western and the central part of the Pacific and

allow the reconstruction of SST. On the contrary there is a critical lack of data in the eastern

part of the Pacific Ocean. In order to fill this void, we present geochemical results (Sr/Cabased

SST) obtained from massive aragonitic coral skeletons (Porites genus) from Clipperton

atoll (10°N, 109°W), ideally located for our scientific purpose. Two coral records accurately

dated by U/Th method covering part of the 12th (end of the Medieval Warm Period) and a part

of the 16th (beginning of the Little Ice Age) centuries will be compared to a 20th century

Clipperton composite record (Wu et al., Palaeo3, 2014). The intensity and frequency of

ENSO events together with the seasonal range of SST in the eastern Pacific over the last

millennium will be discussed.