P2C2: Extratropical Mechanisms, Land-Surface Properties, and Seasonal Precipitation Processes on Saharan Rainfall and Simulation of the African Humid Period

P2C2：撒哈拉降雨的温带机制、地表特性和季节性降水过程以及非洲湿润期的模拟

• 批准号: 1602956
• 负责人: Christopher Poulsen
• 金额: $ 33.1万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1602956&HistoricalAwards=false
• 关键词: P2C2; Extratropical; Mechanisms; Land; Surface

This project generally aims to develop an understanding of seasonal non-monsoon processes in order to quantify their contribution to climate change in northern Africa. Specifically, the research aims to provide insights into the relative contributions of the West African Monsoon (WAM), extratropical cyclones, Mediterranean cold air surges, and tropical plumes to African Humid Period (AHP) rainfall (~14,800 - 5,000 years Before Present. At millennial timescales, northern Africa experienced dramatic climate and environmental change. During the early to mid-Holocene AHP, the world's largest present-day hot desert, the Sahara, received abundant rainfall and supported widespread lakes, wetlands, and vegetation. Given the critical role of the present-day Sahara in Earth's radiation budget and its influence on Sahel rainfall, global mineral dust concentrations, biogeochemical cycles, and tropical cyclogenesis, climate variability in the Sahara, such as that observed during the Holocene, has profound impacts on the global climate system. By evaluating the contribution of these processes to AHP rainfall, the research will assist in interpreting the sources of moisture recorded in proxy records from the Sahara-Arabian desert belt which are currently ambiguous because they lie near the border of the tropical monsoon and mid-latitude rainfall regimes. An assessment of the impact of the new dynamic soil albedo scheme within the Community Earth System Model (CESM) will offer tangible insights for climate model development and improved simulation of the AHP. The development of an objective algorithm for the detection of tropical plumes within general circulation models will be made publicly available and could be used to study the processes that influence tropical plume events across the globe in past, present, and future climates.The Broader Impacts involve the potential for increasing the pipeline of underrepresented minority (URM) students into the earth sciences through our participation in the University of Michigan (U-M) Earth Camp. Earth Camp is a residential camp for early-career, high-school students from the Detroit-area that educates them about the earth sciences and careers in the earth sciences. The U-M Earth Camp has consisted of a single summer experience, but is expanding to a multi-summer camp in order to increase the odds that students will study earth sciences in college. As part of our participation in Earth Camp, the participants in this project will develop and instruct a one-day atmospheric science and climate component to the first summer experience in Ann Arbor, MI and create a four-day component for the second summer experience at the U-M field station in Wyoming. In addition to broadening URM participation in the earth sciences, this project will also support the training and career-development of a young scientist and at least one undergraduate student.

该项目的总体目的是了解季节性非季风过程，以便量化其对北非气候变化的贡献。具体地说，这项研究旨在深入了解西非季风(WAM)、温带气旋、地中海冷空气涌动和热带羽流对非洲湿润期(AHP)降雨量(距今约14800-5000年)的相对贡献。在千年时间尺度上，北非经历了戏剧性的气候和环境变化。在全新世早期至中期，世界上最大的今天最大的炎热沙漠撒哈拉沙漠获得了充足的降雨，并支持了广泛的湖泊、湿地和植被。鉴于当今撒哈拉在地球辐射收支中的关键作用及其对萨赫勒降雨量、全球矿物粉尘浓度、生物地球化学循环和热带气旋发生的影响，撒哈拉的气候变化，如在全新世观察到的气候变化，对全球气候系统产生了深远的影响。通过评估这些过程对AHP降雨量的贡献，这项研究将有助于解释撒哈拉-阿拉伯沙漠带替代记录中记录的水汽来源，这些记录目前尚不明确，因为它们位于热带季风和中纬度降雨制度的边界附近。在共同体地球系统模式(CESM)内对新的动态土壤反照率计划的影响进行评估，将为气候模式的发展和改进AHP的模拟提供切实的见解。在大气环流模式中探测热带羽流的客观算法的开发将公之于众，并可用于研究在过去、现在和未来气候中影响全球热带羽流事件的过程。更广泛的影响包括通过我们参加密歇根大学(U-M)地球营，增加未被充分代表的少数族裔(URM)学生进入地球科学的管道的可能性。地球营是一个为来自底特律地区的初出茅庐的高中生设立的宿营地，旨在教育他们有关地球科学和地球科学职业的知识。密歇根大学地球营由单一的暑期体验组成，但正在扩大为多个夏令营，以增加学生在大学学习地球科学的机会。作为我们参加地球夏令营的一部分，该项目的参与者将开发和指导为期一天的大气科学和气候部分，以获得密歇根州安娜堡的第一次夏季体验，并为怀俄明州U-M野外站的第二次夏季体验创建一个为期四天的部分。除了扩大国际地球科学研究中心的参与外，该项目还将支持一名青年科学家和至少一名本科生的培训和职业发展。