Rekonstruktion von sub- bis interdekadischer Klimavariabilität im westlichen atlantischen Warm Pool basierend auf Korallen und die Verbindung zur Hurrikanaktivität

• Antragsteller: Dr. Carl-Dieter Garbe-Schönberg; Dr. Steffen Hetzinger
• Fachliche Zuordnung: Paläontologie
• Förderung: Förderung von 2012 bis 2016
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 220278536

Atlantic low-frequency sea surface temperature (SST) variability affects climate and ocean changes across much of the Northern Hemisphere, including Atlantic hurricane activity. Tropical Atlantic SST displays a nonlinear upward trend over the 20th century that has been attributed to human-induced global warming (IPCC, 2007). A possible linkage of a recent increase in Atlantic hurricane acticity to global warming has led to an intense debate within the scientific community. However, limitations in existing records (instrument-derived and proxy data) make it impossible to decipher the contributions of man-made warming from natural low-frequency climate variability. This proposal aims to study past changes in surface ocean variability linked to climate and past hurricane activity (e.g. SST and vertical wind shear), extending significantly before existing datasets. The project has multiple components and differs from all previous approaches in that (1) past variability is reconstructed for up to 300 years using coral records from a key area in the Atlantic hurricane domain, (2) high-resolution time series are developed (seasonal instead of annual or even lower resolution), (3) a combination of geochemical proxies (δ18O and Sr/Ca) is utilized, and (4) for the first time geochemical proxies in Diploria sp. corals are calibrated using high-resolution in situ monitoring data. The proposed record is well replicated and calibrated, ensuring that statistically robust inferences can be made about seasonal to multidecadal climate variability going back to the Little Ice Age. Importantly, this new record will be the first seasonally resolved, multiple century paleoclimate record from the Caribbean, yielding a reconstruction of environmental conditions that prevailed during the pre-anthropogenic climate state. This provides a means to validate results from models studying changes in climate and hurricane activity related to future greenhouse gas induced warming scenarios.

• DFG-Verfahren: Sachbeihilfen