Collaborative Research: A multiple-technique approach for deconvolving tropical cyclone effects on Late Quaternary geomorphic change in arid southwestern North America

合作研究：采用多种技术方法解卷积热带气旋对北美干旱西南部晚第四纪地貌变化的影响

• 批准号: 1745734
• 负责人: Jose Luis Antinao Rojas
• 金额: $ 32.68万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1745734&HistoricalAwards=false
• 关键词: Collaborative; Research; multiple; technique; approach

The Eastern Pacific Ocean in the Northern Hemisphere is one of the most prolific regions on Earth in terms of generation of intense tropical cyclones that make landfall on the coasts of arid southwestern North America and dramatically enhance runoff, flooding, and associated erosion and sedimentation. Recent research indicates that these large-scale events have altered the hydrological and ecosystem balances over historical and geological timescales (decades to thousands of years). This project will assess how far north along the coast of southwestern North America these storms have occurred in the geologic past, and how far inland they controlled geomorphic change events through rain and erosion. The specific goal is to determine if previously documented periods when tropical cyclones dominated runoff and sediment deposition across large alluvial fan systems of the southern Baja California peninsula can be detected in central Baja California, the southern California deserts, and even as far north as the southern Arizona Sonoran Desert. Data will test whether dissipating cyclones were drivers of alluvial fan sedimentation over thousands of years, and if a temporal correlation can be established to a period of transition between a milder, humid paleoclimate to the current arid climate. For the first time, a tropical cyclone landfall chronology covering the last few millennia will be developed for the Pacific coast of southwestern North America. This research has the potential to inform large-storm prediction scenarios for southern California and northwestern Mexico, which is relevant to hazards management for communities in need of risk assessment of rare and extreme events. The project will contribute to the training of the next generation of earth scientists using a tiered approach, with field-based collaboration of postdoctoral fellows, graduate and undergraduate students. This approach has been proven successful for inclusion of underrepresented minorities, enhanced also with planned research alongside Mexican collaborators and students. The project will provide unique broader educational experiences for grade-school students in Indiana and Arizona, through the use of technology to connect fieldwork and classrooms.This project will compare a recently established alluvial fan chronology in southern Baja California, with newly-obtained alluvial fan and paleotempestological records. A Holocene paleotempestological record of overwash deposits in the Pacific coastal Vizcaino Desert will be developed for the first time. The inferred tropical storm activity will be compared with inland alluvial fan deposition in this area and in the northern Sonoran Desert, enabling discrimination of signals from different moisture sources, based on observed coastal and alluvial sedimentology, stratigraphy, and specific proxy records. Effects of different sources of moisture that drive sedimentation will be assessed by probing different time periods, and compared to independent paleoclimatic proxies. Bayesian analysis of luminescence, cosmogenic, and radiocarbon geochronology will improve age control precision. The coupled alluvial and coastal record at orbital timescales will help to understand linkages between Quaternary alluvial sedimentation and hydroclimatic variability in the region, and will increase our understanding of basic principles of alluvial fan aggradation in response to change in arid hydroclimates. The project will test effects of millennial- and orbital-scale shifts in tropical circulation on landscape evolution of the region, which are, in turn, critical to test models of occurrence and effects of hydrological extremes and associated landscape changing events.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.

就产生强烈的热带气旋而言，北半球的东太平洋是地球上最多产的地区之一，这些旋风将在北美西南干旱的沿海地区登陆，并大大改善了径流，洪水和相关的侵蚀和沉积物。 最近的研究表明，这些大规模事件已改变了历史和地质时间尺度上的水文和生态系统平衡（数十年至数千年）。该项目将评估沿北美西南部海岸的北部这些风暴发生在地质的过去，以及他们通过雨水和侵蚀控制地貌变化事件的内陆多远。具体的目标是确定在南部巴哈加利福尼亚半岛的大型冲积扇形系统中，热带气旋占主导地位的径流和沉积物沉积是否可以在加利福尼亚州中部，南加州沙漠​​，甚至北至北至亚利桑那州南部的亚利桑那州索诺兰沙漠。数据将测试耗散的旋风是否是数千年来冲积风扇沉积的驱动因素，并且是否可以建立时间相关性，以建立与温和的潮湿的古菌与当前干旱气候之间的过渡期。首次将为北美西南部太平洋海岸开发涵盖最后几千年的热带气旋登陆年表。这项研究有可能为南加州和墨西哥西北部的大型预测情景提供信息，这与需要对罕见和极端事件的风险评估的危害管理有关。该项目将使用分层的方法为下一代地球科学家的培训做出贡献，并通过基于现场的博士后研究员，研究生和本科生的合作。事实证明，通过与墨西哥合作者和学生一起计划的研究，这种方法已被证明成功地包括了代表性不足的少数民族。该项目将通过使用技术连接现场工作和课堂来为印第安纳州和亚利桑那州的年级学生提供独特的更广泛的教育经验。该项目将与新近巴哈加利福尼亚州南部的最近建立的冲积粉丝年表进行比较，并与新近观察到的高级冲积粉丝和古学型记录。将首次开发太平洋沿海维斯卡诺沙漠的全新世古植物记录。推断的热带风暴活动将与该地区和北索诺拉沙漠中的内陆冲积粉丝沉积进行比较，从而基于观察到的沿海和冲积沉积学，地层学和特定的代理记录，从而使来自不同水分源的信号歧视。通过探测不同的时间段并将其与独立的古气候代理进行比较，将评估驱动沉积物的不同水分来源的影响。贝叶斯对发光，宇宙基因和放射性碳的分析将提高年龄控制精度。轨道时间尺度上的耦合冲积和沿海记录将有助于理解该地区的第四纪冲积沉积和氢化气候变化之间的联系，并将增加我们对响应于干旱氢化物质变化的冲积粉丝促进基本原理的理解。该项目将测试热带循环中千禧一代和轨道尺度变化对该地区景观演变的影响，这反过来对水文极端和相关景观改变事件的发生模型和影响至关重要。该奖项反映了NSF的法定任务，并通过评估基金会的Merit和Broadial and crarit和广泛的crakia and Infcestial and Broadia and crarit和宽阔的范围。