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稀少，我们对热带太平洋气候过去如何变化的理解仍然不确定。该研究项目将利用湖泊沉积物来揭示过去1000年中热带太平洋岛屿基里蒂马蒂的降水和蒸发变化。 该项目的成果将使人们深入了解太平洋热带气候变化的性质，这些变化的时间尺度对未来气候趋势至关重要，拟议的研究将产生太平洋热带中部气候的新代用记录。元素丰度的时间序列，湖水电导率的生物指标，介形虫碳酸钙的稳定氧同位素比跨越过去的千年将提供一个多代理的角度来看，过去的湖水平衡和大气水分平衡。此外，新的天气，湖泊和地下水的湖沼和稳定的氧同位素测量将促进更定量的了解气候控制湖泊水平衡的框架内的代理系统模型的湖水和介形虫氧同位素比值。这些新开发的记录将允许假设检验大气环流的纬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中发挥了更突出的作用。

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.