Evolution of ENSO during the Holocene

根据该合同，PIs将在热带太平洋中部的塔拉瓦环礁（1N, 172E）钻探珊瑚礁，试图重建过去1万年的厄尔尼诺/拉尼娜（ENSO）变化。PIs建议基于18O地球化学代理测量海面盐度和温度。国家海洋局在塔拉瓦环礁的初步研究表明，典型的ENSO事件早在距今7760年前就发生了，当时一些研究人员说，他们没有在厄瓜多尔的湖泊沉积物中发现ENSO的证据。ENSO热带太平洋海洋/大气异常是全球气候变率的主要来源，有时会造成灾难性后果。仪器资料和中期及耦合模式表明，热带太平洋的年代际和千禧年尺度海温变化与El Nino/La Nina异常场具有相似的异常模式。一个引人注目的发现是，在距今5000年至12000年之间，海洋/气候变化的ENSO波动在陆地气候代理记录中不存在，这引发了对ENSO模拟和古海洋学社区的新研究。过去一个世纪的气候数据表明，随着热带太平洋异常的频率和强度的变化，一些地区对ENSO的气候响应发生了变化。

Under this award the PIs will drill the reef at Tarawa Atoll (1N, 172E) in the central tropical Pacific in attempt to reconstruct El Nino/La Nina (ENSO) variability over the past 10K years. The PIs propose to measure sea surface salinity and temperature based on the 18O geochemical proxy. The PIs pilot study at Tarawa Atoll shows that typical ENSO events occurred as early at 7,760 years before present, during a time when some researchers say they did not detect evidence for ENSO in Ecuador lake sediments. ENSO tropical Pacific ocean/atmosphere anomalies are a dominant source of global climate variability, sometimes having catastrophic consequences. Instrumental data and intermediate and coupled models indicate that decadal and possibly millennial-scale sea surface temperature variability in the tropical Pacific have similar anomaly patterns to the El Nino/La Nina anomaly fields. A remarkable finding that the ENSO fluctuations of ocean/climate change were absent in terrestrial climate proxy records between 5,000 and 12,000 years before present has sparked new research in the ENSO modeling and paleoceanographic communities. Climate data for the past century show that some regions have changed their climate response to ENSO, as the frequency and intensity of tropical Pacific anomalies changed.