Collaborative Research: Characterizing Northern Hemisphere Atmospheric Variability from Central American Wind Gap-Induced Upwelling

合作研究：通过中美洲风隙引起的上升流来表征北半球大气变化

• 批准号: 2303599
• 负责人: Patrick Rafter
• 金额: $ 49.1万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303599&HistoricalAwards=false
• 关键词: Collaborative; Research; Characterizing; Northern; Hemisphere

There are three locations along the Central American Sierra Madre mountains that are low enough to allow winds to pass from the Atlantic to the Pacific Ocean. The northernmost of these wind gaps is the ‘Tehuantepec Gap’ (along the southwest coast of Mexico). These locally known winds (here simply Tehuantepec Gap Winds) drive intense upwelling of cool, nutrient-rich water in the Gulf primarily in the winter when high atmospheric pressures over North America establish a pressure gradient across the Isthmus of Tehuantepec. Despite the potential importance of the Tehuantepec Gap Winds as an Atlantic-Pacific teleconnection, there has been no attempt to predict the response of these winds to changes in regional climate dynamics in the context of rapid and global climate change. The researchers suggest to combine past climate records of upwelling (from sedimentary radiocarbon over the last 30.000 years) and model simulations to characterize atmospheric dynamical processes over the North Atlantic, and to examine both the sensitivity of these winds to ‘upstream’ factors as well as the ‘downstream’ implications of this inter-basin coupling. A novel Atlantic-Pacific Ocean-atmosphere feedback mechanism is suggesting in the methodological framework and hypothesis testing of this project in which the Tehuantepec Gap Winds and atmospheric Rossby waves play a central role. This collaborative project will support two early career scientists, and the education and scientific training of undergraduate students at UC Irvine (both a Hispanic Serving Institution and Native American Pacific Islander-Serving Institution). The researchers will continue engagement in their institution’ broadening participation efforts, including ATOC REU in Atmospheric, Oceanic, and Cryospheric Sciences (NSF 2150262), a program that primarily recruits from Hispanic Serving Institutions to introduce students to data science and geoscience research. Additionally, a lesson plan focused on long-term variations in Earth’s climate will be developed as part of this project and piloted through Environmental Climate Change and Literacy Projects in California’s outreach programs and posted in an openly available national online repository for climate pedagogy (called “Subject to Climate”).The Gulf of Tehuantepec is an ideal location to characterize ‘upstream’ atmospheric processes linking the Pacific and Atlantic sectors because a prominent gap in the Sierra Madre mountains forces low-level winds to flow through the Isthmus of Tehuantepec toward the Pacific, driving local upwelling of deeper, lower radiocarbon waters to the surface. A preliminary model results and sediment core measurements leverage this wind-to-radiocarbon relationship to provide a precious constraint on Northern Hemisphere atmospheric dynamics over the past 23,000-years. Previous studies of contemporary climate variability and preliminary examinations of models and observational products indicate that higher atmospheric pressure over North America is associated with high near-surface pressure in the Gulf of Mexico, leading to stronger Tehuantepec winds. The project suggested here—including new sediment proxy measurements, model (Paleoclimate GCM) and data product examinations, and forward modeling—aims to discover the driving mechanisms behind the variability in Tehuantepec gap wind strength over paleoclimate timescales, which will provide a crucial new constraint on glacial-interglacial atmospheric dynamics in addition to controls on tropical Pacific Sea Surface Temperature and inter-basin moisture fluxes.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.

中美洲马德雷山脉沿岸有三个位置足够低，可以让风从大西洋吹向太平洋。最北端的风隙是“特万特佩克间隙”（沿着墨西哥西南海岸）。当地已知的风（这里简称为特万特佩克峡风）主要在冬季，当北美上空的高气压在整个地峡形成压力梯度时，会驱动海湾中凉爽、营养丰富的海水强烈上涌。研究人员建议，尽管特万特佩克峡风作为大西洋-太平洋遥相关具有潜在的重要性，但尚未尝试预测这些风在快速全球气候变化的背景下对区域气候动态变化的反应。结合过去的上升流气候记录（来自过去 30,000 年的沉积放射性碳）和模型模拟来表征北大西洋的大气动力学过程，并检查这些风对这种盆地间耦合的“上游”因素以及“下游”影响在该项目的方法框架和假设检验中提出了一种新颖的大西洋-太平洋-大气反馈机制，其中特万特佩克峡风和大气罗斯比。该合作项目将支持两名早期职业科学家，以及加州大学欧文分校（既是西班牙裔服务机构又是美国太平洋岛民服务机构）的本科生的教育和科学培训。参与其机构扩大参与的努力，包括 ATOC REU 的大气、海洋和冰冻圈科学 (NSF 2150262)，该计划主要从西班牙裔服务机构招募学生，向学生介绍数据科学和地球科学研究。此外，还有一个重点课程计划。关于地球气候长期变化的研究将作为该项目的一部分进行开发，并通过加州外展计划中的环境气候变化和扫盲项目进行试点，并发布在公开可用的国家气候在线存储库中教育学（称为“受气候影响”）。特万特佩克湾是描述连接太平洋和大西洋部分的“上游”大气过程的理想地点，因为马德雷山脉的一个显着间隙迫使低层风流经地峡特万特佩克的风向太平洋移动，推动更深、放射性碳含量较低的海水局部上升至地表。初步模型结果和沉积物岩心测量利用了这种风与放射性碳的关系，为北方地区提供了宝贵的约束。过去 23,000 年的半球大气动力学研究以及对模型和观测产品的初步检查表明，北美上空较高的大气压力与墨西哥湾的高近地表压力有关，导致特万特佩克气强。这里建议的项目——包括新的沉积物替代测量、模型（古气候 GCM）和数据产品检查以及正演建模——旨在发现特万特佩克间隙风变化背后的驱动机制。古气候时间尺度上的强度，除了对热带太平洋海面温度和流域间水分通量的控制之外，这将为冰期-间冰期大气动力学提供重要的新约束。该奖项反映了 NSF 的法定使命，并通过评估被认为值得支持利用基金会的智力优势和更广泛的影响审查标准。