Collaborative Research: Developing Records of Hydroclimate Variability in the Southeastern United States from the Middle Holocene to Present-Day

美国东南部是一个重要的农业区，但最近的洪水和干旱事件已造成数十亿美元的经济损失。人们对降水蒸发（水文气候）趋势变化的驱动因素缺乏了解，部分原因是与美国其他地区相比，该地区的古气候记录较少。该项目将从四湖收集沉积物岩心，两个在北方格鲁吉亚和亚拉巴马，两个在南部。预计这些地区将根据主要控制水文气候的因素作出不同的反应。该项目将确定这些湖泊是否有记录，这些记录是否适合进一步深入研究过去5000年，并最终确定什么是水文气候的重要控制因素，以及它如何随时间变化。该项目的中心假设是，从4000年BP开始，美国东南部的水文气候主要受太平洋北美型的控制，该型表现为在所选区域的降水偶极子。研究中心。该项目将重点关注：1）从沉积中心和样带岩心中收集沉积物序列的年代测定，2）确定沉积物积累是否足以验证假设，3）记录收集的岩心中的地层序列。对沉积物中的物理（粒度）、地球化学（碳和氮）和生物（花粉）参数的初步研究也将确定进行进一步研究的可行性。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The Southeastern United States is an important agricultural region, but recent flooding and drought events have caused billions of dollars in economic loss. There is a lack of understanding about what drives changes in precipitation-evaporation (hydroclimate) trends, in part because there are fewer paleoclimate records from this region compared to the rest of the United States. This project will collect sediment cores from four lakes, two in northern Georgia and Alabama and two in the south. These regions are expected to respond differently depending on what predominantly controls hydroclimate. This project will establish if these lakes have records that are suitable for further, in-depth study of the past 5000 years and can ultimately identify what is an important control of hydroclimate and how it changed through time.This project’s central hypothesis is that from 4000 years BP onwards, hydroclimate in the Southeastern United States has been predominantly controlled by the Pacific North American pattern which manifests as a precipitation dipole at the selected study sites. This project will focus attention on: 1) dating the collected sediment sequences from depocenter and transect cores, 2) establishing whether sediment accumulation is sufficient enough to test the hypothesis, and 3) documenting the stratigraphic sequences in the collected cores. Preliminary work on physical (grain size), geochemical (carbon and nitrogen), and biological (pollen) parameters in the sediments will also establish the feasibility of pursuing additional study.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.