Collaborative Research: High-Resolution, Low-Latitude Paleoclimatology From Newly Acquired Sediment Drill Cores From Lake Bosumtwi, Ghana

合作研究：来自加纳博苏姆特维湖新获得的沉积物钻芯的高分辨率、低纬度古气候学

• 批准号: 0601998
• 负责人: Jonathan Overpeck
• 金额: $ 24.47万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0601998&HistoricalAwards=false
• 关键词: Collaborative; Research; Resolution; Low; Latitude

Lake Bosumtwi lies in a million-year-old meteorite impact crater located in the tropical forest lowlands of Ghana, in West Africa. The lake is hydrologically closed and known to be very sensitive to the precipitation/evaporation balance and the strength of the West African Monsoon. Lake Bosumtwi contains one of a very few, long annually laminated sediment records in the tropics, and has by far the longest, highest-resolution paleoclimate record in equatorial West Africa.Intellectual Merit: This grant studies interannual to millennial-scale West African monsoon dynamics over the last ~430 kyr (i.e., back through Marine Isotopic Stage [MIS] 11). This work provides insight into the role of the tropics in triggering, intensifying and propagating climate changes, as well as in responding to global and highlatitude changes. This work will produce the first continuous well-dated terrestrial record of West African climate & aerosol variability over multiple glacial cycles, and provide hydrologic constraints on a key methane source region, and use the annually-laminated sediments to examine globally significant questions regarding the exact timing and patterns of change over multiple glacial terminations (e.g., What is the low-latitude response to deglaciation events, and can we assess how fast large ice sheets melt and lead to interglacial conditions? What is the nature of climatic reversals on previous terminations? How long was MIS11, how was it manifested in the tropics, and how does it really relate to orbital forcing, particularly at the end? What is the full range of drought variability during warm climates?)

博苏姆特维湖位于西非加纳热带森林低地的一个有百万年历史的陨石撞击坑中。该湖在水文上是封闭的，已知对降水/蒸发平衡和西非季风的强度非常敏感。博苏姆特维湖包含了热带地区为数不多的、长期的年度层状沉积物记录之一，并且拥有迄今为止赤道西非地区最长、分辨率最高的古气候记录。学术价值：该基金研究了过去~430 kyr（即，海洋同位素阶段（Marine Isotopic Stage，MIS 11）这项工作使人们深入了解热带地区在引发、加剧和传播气候变化以及应对全球和高纬度变化方面的作用。这项工作将产生西非气候气溶胶变化在多个冰川循环中的第一个连续的日期明确的陆地记录，并提供对关键甲烷源区的水文限制，并使用年度分层沉积物来研究有关多个冰川终止的确切时间和变化模式的全球重要问题（例如，低纬度地区对冰川消退事件的反应是什么？我们能否评估大冰盖融化的速度并导致间冰期的条件？以前终止的气候逆转的性质是什么？MIS 11有多长时间，它在热带地区是如何表现的，它与轨道强迫有什么关系，特别是在最后？在温暖的气候条件下，干旱的全部变化范围是什么？）