Last Interglacial Variability in the Tropical Atlantic Warm Pool

Authors: Kristine DeLong*, Louisiana State University, Gilman Ouellette, Louisiana State University, Nathalie Goodkin, Nanyang Technological University, Elinor Martin, University of Oklahoma, Derek Rosenthal, University of Oklahoma, Frederick Taylor, University of Texas at Austin, Chuan-Chou Shen, National Taiwan University
Topics: Paleoenvironmental Change, Climatology and Meteorology, Coastal and Marine
Keywords: coral, temperature, Hispaniola, Caribbean, last interglacial
Session Type: Paper
Day: 4/10/2018
Start / End Time: 10:00 AM / 11:40 AM
Room: Napoleon B2, Sheraton 3rd Floor
Presentation File: No File Uploaded

The Last Interglacial (LIG), when sea level was ~6 m higher than today, serves as an analog for future climate scenarios yet few paleoclimatic reconstructions have the seasonal–decadal resolution needed to investigate climate variability on these scales. The Atlantic Warm Pool (AWP; SST >28.5ºC) is a primary moisture source region for precipitation in Central and North America that experiences spatial-temporal variations. We present an early LIG (128.6 ka) monthly-resolved sea surface temperature (SST) reconstruction from a well-preserved Siderastrea siderea coral from northern Hispaniola spanning 75 years, which is the longest LIG coral record. We compare our LIG SST reconstruction with three modern S. siderea microatolls western Hispaniola, longest spanning 84 years, as well as the CCSM3 125 ka LIG model simulation. We find similar LIG seasonal SST cycles in the coral (3.7ºC) and simulation (3.8ºC) that are greater than those in the modern corals, observed SST, and CCSM3 20th century simulation, which is broadly consistent with other shorter LIG Atlantic coral studies, suggesting orbital insolation changes are driving LIG SST seasonality in this region. Furthermore, our LIG reconstruction reveals larger multidecadal (2.8ºC, ~20–30 years/cycle) and interannual variability (3.0ºC, ~3–8 years/cycle) than the modern coral and SST records yet similar variability is present in the LIG model simulation but with a reduced magnitude. This interannual and decadal variability may reflect variations in the northern extent of the AWP on these time scales, which may covary with trade wind strength, westward moisture transport and precipitation in the AWP region.

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