A Terrestrial Perspective of Last Millennium Hydroclimate Variability in the Central Tropical Pacific

热带太平洋在塑造全球气候模式方面发挥着巨大的作用，但由于对这一广阔地区的观测很少，我们对过去热带太平洋气候变化的理解仍然不确定。该研究项目将利用湖泊沉积物揭示热带太平洋中部基里蒂马蒂岛在过去1000年里降水和蒸发的变化。该项目的成果将有助于深入了解多年代际至百年代际热带太平洋气候变化的性质，这些时间尺度在未来气候趋势的背景下至关重要。拟议中的研究将产生热带太平洋中部气候的新代用记录。元素丰度、湖泊水电导率的生物指标和介形虫碳酸钙稳定氧同位素比值的时间序列将为过去湖泊水平衡和大气水分平衡提供多代理视角。此外，新的湖泊和地下水的天气、湖泊和稳定氧同位素测量将有助于在湖泊水和介形虫氧同位素代用系统模型的框架内更定量地了解气候对湖泊水平衡的控制。这些新开发的记录将允许对大气环流中的经向或纬向变化是否在控制热带太平洋水文气候变异的空间格局方面发挥更突出的作用进行假设检验。

The tropical Pacific plays an enormous role in shaping global climate patterns, yet our understanding of how tropical Pacific climate has varied in the past remains uncertain due to sparse observations across this vast region. This research project will use lake sediments to reveal changes in precipitation and evaporation on the central tropical Pacific island of Kiritimati during the last 1000 years. The outcomes of this project will provide insight into the nature of multidecadal to centennial tropical Pacific climate variability, timescales critical in the context of future climate trends.The proposed research will produce new proxy records of central tropical Pacific climate. Time series of elemental abundance, biological indicators of lake water conductivity, and stable oxygen isotope ratios of ostracod calcium carbonate spanning the last millennium will provide a multi-proxy perspective on past lake water balance and atmospheric moisture balance. In addition, new weather, limnologic and stable oxygen isotope measurements of lake and groundwater will promote a more quantitative understanding of the climate controls on lake water balance within the framework of a proxy system model for lake water and ostracod oxygen isotope ratios. These newly developed records will permit hypothesis testing of whether meridional or zonal changes in atmospheric circulation played a more prominent role in controlling spatial patterns of tropical Pacific hydroclimate variability.