High-Resolution Climatic Variability in the Southwestern U.S. During the Last Millennium

摘要ATM-9615875 Ku，南加州德隆大学 上个千年美国西南部高分辨率气候变化 该奖项支持一个研究项目，旨在开发一个有效的代理工具，这将使PI重建降水变率的次十年（3-10年）的时间尺度在过去的千年在美国西南部这是一个地区（至少南部）的大气遥相关与厄尔尼诺/南方涛动（ENSO）事件。 关键的方法是采用高分辨率的氧同位素测量的碳酸盐沉积物从封闭的盆地湖泊位于沿着一个N-S样带在俄勒冈州，加州和内华达州。 该方法的基础在于，通过降雨和径流进入封闭流域湖泊的水主要通过蒸发离开，湖泊的同位素组成反映了水文平衡，用于监测区域气候变化，特别是降水变率，在给定的时间。 湖泊沉积物中自生碳酸盐矿物记录了湖水同位素组成的历史变化。 最近在莫诺湖进行的一项研究测试了拟议研究的可行性。 该方法将允许PI评估水分来源（来自三个气候系统：太平洋，大陆和墨西哥湾）及其相对强度，并检测风暴路径在时域中的任何变化。 预计这项研究将使研究所能够评估小冰期、中世纪暖期和厄尔尼诺/南方涛动等气候异常，并有助于了解十年以下气候变率的原因和动态。

Abstract ATM-9615875 Ku, Teh-Lung University of Southern California Title: High-Resolution Climatic Variability in the Southwestern U.S. During the Last Millennium This award supports a research project aimed at developing an effective proxy tool which will enable the PIs to reconstruct the precipitation variability on sub-decadal (3-10 years) time scales for the past millennium in the southwestern U.S. This is a region (at least the southern part) of atmospheric teleconnection associated with the El Nino/Southern Oscillation (ENSO) events. The key approach is to employ the high-resolution oxygen isotopic measurement on dated carbonate sediments retrieved from closed- basin lakes located along a N-S transect in Oregon, California and Nevada. The basis for the approach lies in the fact that water entering a closed-basin lake via rain and runoff mostly leaves by evaporation, and the lake's isotopic composition reflects the hydrologic balance that serves to monitor the regional climate change, especially the precipitation variability, at a given time. Past variations of lake water isotopic composition are recorded by authigenic carbonate minerals of the lacustrine sediment. The feasibility of the proposed research has been tested in a recent study conducted in Mono Lake. The method will allow the PIs to assess the moisture sources (from three climatic regimes: Pacific, continental, and Gulf of Mexico) and their relative strengths and detect any shifts in storm track in the time domain. It is anticipated that the study will allow the PIs to evaluate such climatic anomalies as the Little Ice Age, Medieval Warm Period, and ENSO, and contribute to the understanding of the causes and dynamics of sub-decadal climatic variability.