Tracking Sea-level Source Contributions: A Hemispheric Approach to High Resolution Sea-level Variation Over the Last Two Millennia

跟踪海平面源贡献：过去两千年高分辨率海平面变化的半球方法

• 批准号: 1154978
• 负责人: Jeffrey Donnelly
• 金额: $ 25.26万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1154978&HistoricalAwards=false
• 关键词: Tracking; Sea; level; Source; Contributions

Accurate estimates of sea-level rise in the pre-satellite era are needed to provide appropriate context for 21st century projections and to validate geophysical and climate models. Exploring geographic trends in sea level are critical for this because sea-level changes are not globally uniform and involve isostatic deformation of the solid Earth along with gravitational and rotational changes driven by the exchange of mass between oceans and ice sheets. The aim of the study is to produce high-resolution reconstructions of sea-level change for the past two millennia along the Atlantic coasts of South Africa and Argentina. Relative sea levels along these coastlines are influenced by melting of both the Greenland and Western Antarctic Ice Sheets (GIS and WAIS). Four hypothetical hypotheses related to the timing and magnitude of sea-level changes: (1) The magnitude of sea-level rise since AD ~1850 is greater in Argentina and South Africa than New England which may indicate more ice-melt contribution from the GIS; (2) The magnitude of the deceleration in relative sea-level rise associated with the Little Ice Age (c. AD 1500-1850) is greater in New England then in South Africa or Argentina; (3) The magnitude of relative sea-level rise during the Medieval Climate Anomaly (c. AD 1000-1500) increased more in New England then in South Africa and Argentina; and (4) The magnitude of relative sea-level change prior to AD 1000 was slower than that since AD 1000 to present. New microfossil-based transfer functions approach to sea-level reconstruction in salt-marsh sediments will be used ot develop a high-resolution record. This approach combined with a suite of complementary dating methods affords the ability to precisely constrain the chronology (decadal to centennial age resolution) of subtle changes in sea level. In this project, high-resolution relative sea-level reconstructions spanning the past 2000 years will be obtained from South Africa and Argentina. And compared to existing records from New England after they have been corrected for glacial isostatic adjustment (GIA) and steric influences. This project will lead to an increased understanding of the driving mechanisms of sea-level change and could enhance predictions of 21st century sea-level rise and thus has important societal relevance. The project will support an early career PI and graduate students.

需要对前卫星时代的海平面上升进行准确估计，以便为21世纪的预测提供适当的背景，并验证地球物理和气候模型。探索海平面的地理趋势是至关重要的，因为海平面变化不是全球统一的，涉及固体地球的均衡变形沿着海洋和冰盖之间质量交换驱动的重力和旋转变化。这项研究的目的是对过去沿着南非和阿根廷大西洋沿岸的海平面变化进行高分辨率的重建。沿这些海岸线的相对海平面沿着受到格陵兰和南极西部冰盖融化的影响（地理信息系统和WAIS）。对海平面变化的时间和幅度提出了四种假设：（1）自公元1850年以来，阿根廷和南非海平面上升幅度大于新英格兰，这可能表明地理信息系统对海平面变化的贡献更大;（2）与小冰期（c.公元1500-1850年）是更大的新英格兰然后在南非或阿根廷;（3）相对海平面上升的幅度在中世纪气候异常（c。（4）1000年以前的相对海平面变化幅度小于1000年至今的相对海平面变化幅度。新的基于微体化石的传递函数方法将用于盐沼沉积物中的海平面重建，以开发高分辨率记录。这种方法与一套互补的测年方法相结合，能够精确地限制海平面微妙变化的年表（十年到百年的年龄分辨率）。在该项目中，将从南非和阿根廷获得过去2000年的高分辨率相对海平面重建。并与新英格兰的现有记录进行了冰川均衡调整（GIA）和空间影响的校正后进行了比较。该项目将加深对海平面变化驱动机制的理解，并可能加强对21世纪海平面上升的预测，因此具有重要的社会意义。该项目将支持早期职业PI和研究生。