|TITLE||PAST MILLENNIUM MEDITERRANEAN CLIMATE FROM VERMETID SST PROXIES AND CMIP5 MODELS|
|AUTHORS||Y Amitai (1), R Yam (1), P Montagna (2), A Shemesh (1)|
- Weizmann Institute of Science, Rehovot, Israel
- Marine science institute (ISMAR), Bologna, Italy
|ABSTRACT||Reef builders vermetid skeletons provide a high resolution reconstruction of the last millennium Mediterranean climate. Vermetid cores obtained from the west, central and east Mediterranean reveals that the different parts of the Sea surface have different thermal behaviors throughout the last millennium.
The Sea Surface Temperature (SST), extracted from oxygen isotope measurements, show a signal of the Little Ice Age and of the Medieval Warm Period that is more apparent in the west and central Mediterranean while almost absent in the eastern Mediterranean. The rate of warming in the recent Industrial Period (1800 until present day) is also different according to the SST proxies. In the eastern Mediterranean the rate of warming is 0.54°C/100y, and it is more moderate in the western (0.46°C/100y) and central (0.35°C/100y) Mediterranean.
By analyzing atmosphere-ocean coupled models from the CMIP5 project, that simulate the global climate of the past 1000 years, we aim to reconcile these behaviors with the variability of the North Atlantic Oscillation (NAO) and of the South Asia Monsoon (SAM) climate systems. We show a favorable impact of the NAO on the western and central Mediterranean and a favorable impact of the SAM on the eastern Mediterranean. This might explain the different in the observed SST signals during the last millennium.|