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: 2303600
• 负责人: SARA SANCHEZ
• 金额: $ 17.53万
• 依托单位: University of Colorado at Boulder
• 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=2303600&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.

沿着中美洲马德雷山脉有三个沿着的地方，它们足够低，可以让风从大西洋吹到太平洋。这些风隙中最北端的是“特万特佩克峡”（沿着墨西哥西南海岸）。这些当地已知的风（这里简称为特万特佩克峡风）主要在冬季驱动墨西哥湾凉爽、营养丰富的海水强烈上涌，当时北美上空的高气压在特万特佩克地峡建立了一个压力梯度。尽管特万特佩克间隙风作为南极-太平洋遥相关具有潜在的重要性，但在快速和全球气候变化的背景下，还没有尝试预测这些风对区域气候动态变化的反应。研究人员建议将过去的上升流气候记录（来自过去30.000年的沉积放射性碳）和模型模拟相结合，以表征北大西洋上空的大气动力学过程，并研究这些风对“上游”因素的敏感性以及这种盆地间耦合的“下游”影响。一个新的南极-太平洋-大气反馈机制建议在该项目的方法框架和假设检验中，特万特佩克间隙风和大气Rossby波起着核心作用。这个合作项目将支持两个早期的职业科学家，并在加州大学欧文分校（无论是西班牙裔服务机构和美洲原住民太平洋岛民服务机构）的本科生的教育和科学培训。研究人员将继续参与他们机构的扩大参与工作，包括大气，海洋和冰冻圈科学的ATOC REU（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，本发明还作为该项目的一部分，将制定一个以地球气候长期变化为重点的课程计划，并通过加州的环境气候变化和扫盲项目进行试点，并将其发布在一个开放的国家气候教育在线资源库中（称为“受气候影响”）30.特万特佩克湾是描述连接太平洋和大西洋的“上游”大气过程的理想地点，因为马德雷山脉的一个突出缺口低层风通过特万特佩克地峡流向太平洋，推动当地较深、放射性碳含量较低的沃茨上升至地表。初步模型结果和沉积物芯测量利用这种风与放射性碳的关系，为过去23,000年来北方半球大气动力学提供了宝贵的约束。以往对当代气候变率的研究以及对模型和观测产品的初步审查表明，北美上空的高气压与墨西哥湾的高近地面压力有关，导致特万特佩克风增强。该项目建议在这里-包括新的沉积物代用测量，模型（古气候GCM）和数据产品检查，以及正演模拟-旨在发现特万特佩克间隙风强度在古气候时间尺度上变化背后的驱动机制，这将提供一个关键的新的约束冰川间冰期大气动力学除了控制热带太平洋海面温度和间该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。