Doctoral Dissertation Research: Paleohurricane Proxy Records from the Pacific Coast of Mexico

博士论文研究：墨西哥太平洋海岸的古飓风代理记录

• 批准号: 1003654
• 负责人: Kam-biu Liu
• 金额: $ 1.18万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1003654&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Paleohurricane; Proxy

To infer long-term patterns of tropical cyclone activity, it is imperative to collect and interpret data beyond the historical observational period. Paleotempestology is a relatively young science that studies past tropical cyclone activity mainly by means of geological proxy techniques. Paleotempestological research has been successfully conducted at many locations along the U.S. Gulf and Atlantic coasts and the pan-Caribbean region, but proxy records are notably lacking from the Pacific coast of Mexico. Doctoral student Thomas Bianchette under the supervision of Professor Kam-biu Liu will establish a centennial-to-millennial record of paleohurricane strikes from Jalisco and Guerrero on Mexico's Pacific coast using coastal lake-sediment proxies. The geomorphic setting of the study sites and the typical tracks and strengths of tropical cyclones in this region suggest that hurricane strikes will be identifiable in these sediments. In addition to using overwash sand layers as a storm surge proxy, this study will pioneer a new methodology using slopewash deposits and fossil pollen as supplementary proxies to detect indirect hurricane strikes resulting from coast-parallel storms that bring heavy precipitation but do not make landfall (i.e., limited storm surge). The methodology will be based on the hypothesis that increased storm activity during an active period on centennial timescales will result in a wetter climate, leading to a long-term vegetation response that can be detected in the pollen record. Recent storms that have caused a geological and/or biological imprint will be used as modern analogs to aid in interpreting older storm events in the sedimentary record. A geographic information system will be developed to visualize the relationship between historical storm tracks and climate conditions (especially El-Nino/Southern Oscillation), while remote sensing technologies will be used to determine the geomorphological and biophysical effects of recent hurricanes. We hypothesize that a longer return period will be found for tropical cyclones along this coast than for the U.S. Gulf and Atlantic coasts based on multi-millennial data, with northern areas (Jalisco) on Mexico's Pacific coast exhibiting a higher storm frequency than southern locations (Guerrero).This research promises to produce the first proxy records of tropical cyclone activity along the Pacific coast of Mexico. Because unraveling global tropical cyclone activity depends upon inter-basin correlations, proxy records of long-term activity regimes for the Eastern North Pacific basin are vital. The new methodology of using slopewash deposits and fossil pollen as supplementary proxies can advance paleotempestological studies by permitting the use of inland sites and detecting paleo-storm events that brought excessive rain but did not cause significant overwash processes. Furthermore, this study will have great societal relevance as historical tropical cyclone strikes along Mexico's Pacific coast have caused tremendous damage to society and infrastructure, including significant public health problems. Mexico's instrumental record of these storms is very short (since 1949), making long-term risk assessment difficult. Establishing more reliable estimates of hurricane return periods based on multi-centennial or millennial proxy records can help inform decision makers, thereby improving planning and mitigation policy.

为了推断热带气旋活性的长期模式，必须收集和解释历史观察期之外的数据。 古植物学是一门相对年轻的科学，它主要通过地质代理技术研究了热带气旋活动。 古植物学研究已在美国海湾和大西洋沿岸和加勒比海地区的许多地方成功进行，但是墨西哥太平洋海岸的代理记录尤其缺乏。 在Kam-biu教授的监督下，博士生托马斯·比安切特（Thomas Bianchette）将建立一百年至千年的记录，记录了墨西哥太平洋海岸的jalisco和guerrero的古旋转行动，使用沿海湖泊森林遗产。 研究地点的地貌环境以及该地区热带气旋的典型轨道和强度表明，在这些沉积物中将可以识别飓风的罢工。 除了将层面层层用作风暴潮代理外，这项研究还将使用斜率沉积和化石花粉作为补充代理进行新的方法，以检测由海岸平行风暴引起的间接飓风袭击，这些风暴带来了巨大的降水量，但不会带来巨大的降水量，但不会造成登陆（即，风暴涌现）。该方法将基于以下假设：在百年纪念时间尺度上，在活跃时期的风暴活动增加将导致气候较高，从而导致长期的植被反应，可以在花粉记录中检测到。 造成地质和/或生物学烙印的最近风暴将用作现代类似物，以帮助解释沉积记录中的旧风暴事件。 将开发一个地理信息系统，以可视化历史风暴轨迹与气候条件（尤其是El-Nino/Southern振荡）之间的关系，而遥感技术将用于确定最近飓风的地貌和生物物理效应。 We hypothesize that a longer return period will be found for tropical cyclones along this coast than for the U.S. Gulf and Atlantic coasts based on multi-millennial data, with northern areas (Jalisco) on Mexico's Pacific coast exhibiting a higher storm frequency than southern locations (Guerrero).This research promises to produce the first proxy records of tropical cyclone activity along the Pacific coast of Mexico. 由于揭开的全球热带气旋活动取决于巴蛋白间的相关性，因此东北太平洋盆地长期活动制度的代理记录至关重要。 使用斜坡沉积物和化石花粉作为补充代理的新方法可以通过允许使用内陆场所并检测到过多的降雨但不会引起大量过度冲洗过程的古型事件来提高古植物学研究。 此外，这项研究将具有很大的社会意义，因为墨西哥太平洋海岸的历史热带气旋罢工已对社会和基础设施造成了巨大损害，包括重大的公共卫生问题。 墨西哥对这些风暴的工具记录非常短（自1949年以来），这使得长期风险评估变得困难。 基于多个百年或千禧一代的代理记录，建立更可靠的飓风返回期估算值，可以帮助您告知决策者，从而改善计划和缓解政策。