Paleoflood Hydrology

古洪水水文学是一种结合地质学和地表水水文学原理，在直接测量或系统观测之前重建洪水的震级-频率特征的技术。死水沉积-古阶段指示器(SWD-PSI)古洪水研究使用洪水的具体证据来确定稳定(基岩控制)河道环境中的古洪水水位，并使用水力模拟和地质年代学方法重建单个洪水事件的规模和频率。SWD-PSI区域研究提供了在将洪水频率的空间和时间变化与长时间(数千年)的全球气候条件变化联系起来方面不可或缺的数据。我们建议建立一种系统的方法，将古洪水数据纳入水文气候学背景，以帮助了解全球气候和区域洪水频率之间的基本联系。这一方法将依赖对观测到的水文气候数据集的详细分析，以制定一个对尺度敏感、以环流为基础的概念框架，用于评估古洪水记录所代表的时间尺度上的水文气候变异性。在开发过程中，我们计划在对气候变化特别敏感的地区使用这种方法来解决洪水与气候的联系。这些方法还将用于继续研究亚利桑那州的区域古洪水特征与过去5000年来全球气候变化之间的关系。我们在亚利桑那州南部的工作将集中在小型流域(25平方公里)，以补充该地区以前的研究，这些研究侧重于受不同水文气候学机制洪水影响的相当大的流域。我们拟议的研究结果将为极端事件对气候变化的反应提供重要的新见解，并可能对未来全球气候变化产生重要影响。

Paleoflood hydrology is a technique that combines elements of geology and surface water hydrology to reconstruct magnitude- frequency characteristics of floods that occurred prior to direct measurement or systematic observation. Slackwater deposit- paleostage indicator (SWD-PSI) paleoflood studies use specific evidence of flooding to define paleoflood levels in stable (bedrock-controlled) channel environments and use hydraulic modeling and geochronological methods to reconstruct the magnitude and frequency of individual flood events. Regional SWD-PSI studies provide data that are indispensable in relating spatial and temporal variations in flood frequency to global-scale variations in climatic conditions over long time period (1000s of years). We are proposing to establish a systematic method for incorporating paleoflood data into a hydroclimatological context to aid in understanding fundamental linkages between global climate and regional flood frequency. This method will rely on detailed analysis of observed hydroclimatic data sets to develop a scale- sensitive, circulation-based conceptual framework for use in assessing hydroclimatic variability over time scales represented by paleoflood records. In the course of development, we plan to use this method to address the flood-climate linkage in areas particularly sensitive to climatic variations. The methods will also be used in a continuation of research on the relationship between the regional paleoflood characteristics of Arizona and global climatic variations over the past 5000 years. Our work in southern Arizona will focus on small drainage basins(25km2) to augment previous studies in the region that have focused on considerably larger basins subject to flooding from different hydroclimatologic mechanisms. The results of our proposed research will offer important new insights into the response of extreme events to climatic variation and may have important implications for future changes in global climate.