Last Glacial Maximum Tropical Pacific Thermocline Structure and Wind Field: A Data Synthesis

末次盛冰期热带太平洋温跃层结构和风场：数据综合

基本信息

批准号：
2002297
负责人：
Jean Lynch-Stieglitz
金额：
$ 44.97万
依托单位：
Georgia Tech Research Corporation
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-15 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2002297&HistoricalAwards=false
关键词：
Last Glacial Maximum Tropical Pacific

项目摘要

The spatial pattern of wind and rainfall in the tropics is not fixed, but changes with time. The changes can be driven by the amount of greenhouse gasses in the atmosphere, changes in seasonality, or the presence of large expanses of ice outside of the tropics. By looking at these patterns during the height of the last ice age, ideas about the links between these drivers and the tropical climate can be tested. It would be difficult to directly deduce the patterns of the ice age winds. But when the winds blow on the upper ocean, they pile up warm water in some areas and bring cold water closer to the sea surface in others. In this project, the investigators will use tiny shells (foraminifera) that contain information about the temperature of seawater at different depths. These shells accumulate on the sea-floor and preserve a history of ocean temperature. The upper ocean temperature reconstructed from shells that fell to the seafloor during the height of the last ice age can then be used to deduce the wind patterns. The project would support two graduate students (one of whom is a woman from an underrepresented minority), as well as providing support for undergraduate summer researchers.The PIs proposes a plan of database development and analysis that will use the information about the thermocline structure recorded in the oxygen isotope composition of surface and subsurface planktonic foraminifera in the tropics to reconstruct the tropical thermocline and winds during the Last Glacial Maximum. The isotopic composition of the tests of different species will reflect the surface and subsurface density and can be used to reconstruct thermocline structure. The tight coupling between winds and thermocline structure will be exploited to infer changes in the winds through the thermocline reconstructions provided from the foraminifera proxy data. The PIs will first create a global database of tropical planktonic foraminifera oxygen isotope data from recent sediments. Using this data, models for foraminifera calcification habitat will be constructed and the uncertainty in the calcification habitat quantified. A variety of statistical approaches will then be explored in order to determine how to project the sparse information about the vertical structure of the water column from the foraminiferal proxy data into estimates of the tropical thermocline structure, and to determine how to optimally estimate the long-term mean winds associated with a given mean thermocline state. These analytical approaches will include Empirical Orthogonal Functions, Optimal Linear Estimators, and Inverse Methods. Finally, existing Last Glacial Maximum oxygen isotope data will be compiled for these same species. The database will be augmented in the Tropical Pacific with new measurements, as guided by the data analysis effort. Once the Last Glacial Maximum foraminiferal database is complete the data will be directly compared to results from isotope-enabled general circulation model simulations of ice age climate, and also used to produce an estimate of Tropical Pacific thermocline structure and winds using the data analysis tools developed as described above.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.

热带风的风和降雨的空间模式不是固定的，而是随着时间的变化而变化。这些变化可以由大气中的温室气体量，季节性变化或热带地区以外的大量冰膨胀。通过在上一个冰河时代的高峰期查看这些模式，可以测试有关这些驱动因素与热带气候之间联系的想法。很难直接推断出冰河时代的风格。但是，当风在上大洋上吹来时，它们在某些地区堆积了温水，使冷水在其他地区更靠近海面。在这个项目中，研究人员将使用微小的壳（有孔虫），其中包含有关不同深度海水温度的信息。这些贝壳积聚在海底，并保留海洋温度的史。然后，可以使用从掉到海底的贝壳上重建的高海洋温度，然后可以使用来推断风模式。 The project would support two graduate students (one of whom is a woman from an underrepresented minority), as well as providing support for undergraduate summer researchers.The PIs proposes a plan of database development and analysis that will use the information about the thermocline structure recorded in the oxygen isotope composition of surface and subsurface planktonic foraminifera in the tropics to reconstruct the tropical thermocline and winds during the Last冰川最大。不同物种测试的同位素组成将反映表面和地下密度，可用于重建热跃层结构。风与热跃层结构之间的紧密耦合将被利用，以通过有孔虫代理数据提供的热跃层重建来推断风的变化。 PIS将首先创建一个来自最近沉积物的热带浮游有孔虫氧同位素数据的全局数据库。使用这些数据，将构建有孔虫钙化栖息地的模型，并量化钙化栖息地中的不确定性。然后，将探索各种统计方法，以确定如何将有关水柱的垂直结构投影从有孔虫的代理数据中的垂直结构，以估算到热带热层级结构的估计，并确定如何最佳估计与给定平均热级别级别状态相关的长期平均风。这些分析方法将包括经验正交函数，最佳线性估计器和逆方法。最后，将针对这些相同的物种编译现有的最后一次冰川最大同位素数据。在数据分析工作的指导下，数据库将在热带太平洋地区进行新的测量。一旦完成最后的冰川最大有孔数据库，将直接将数据与具有同位素的一般循环模型模型的结果直接进行比较，冰期气候的仿真模拟模拟，也用于对热带太平洋热级热线结构进行估计，并使用如上所述开发的数据分析工具，以上所述的数据分析工具，这些奖项反映了NSF的法规及其在范围内的范围，并且在范围内的范围及其构成的范围及其构成的构成及其构成的构成，并在范围内得到了依据。标准。