Transport Dynamics of the Northeast Pacific In a Changing Climate

在过去的几十年里，东北太平洋(NEP)经历了气候的戏剧性变化，在2013-2019年期间发生了一系列破纪录的极端温度，例如多年来2013-15年的东北太平洋海洋热浪，2015-16年的强烈厄尔尼诺现象，以及最近正在进行的2019年阿拉斯加热浪。由此导致的阿拉斯加湾(GOA)和加州海流系统(CCS)的温度和涡旋尺度海洋输送动力学(例如跨岸、近岸、上升流)的变化导致了巨大的生态系统影响，包括沿海有害的藻类大量繁殖、初级生产力低下、哺乳动物和鸟类大量死亡。尽管我们对太平洋大范围变化的理解取得了进展，但仍不清楚GOA和CCS的区域运输动态如何应对在NEP中观测到的气候极端和十年气候变化趋势，以及在人为气候强迫下运输统计数据预计会发生什么变化。主要问题：(Q1)过去几十年来，东北太平洋区域气候差异的扩大如何影响加州和阿拉斯加湾环流系统中的涡旋尺度输送动力学(例如，近岸、跨岸、上升流)？(Q2)在最近的极端温度(2013-2019年)期间，控制区域海洋运输统计数据的太平洋大尺度驱动因素是什么？在历史长期变化(1950-2000年)的背景下，运输的变化是否显著(例如极端)？(Q3)在人为强迫下(2050-2100)，东北太平洋与生态相关的交通统计数据预计会发生怎样的变化，这些变化与最近极端天气(2013-2019年)期间发生的变化是否一致？这项研究的目标是确定和估计东北太平洋与生态相关的涡度输送动力学对(目标1)最近大尺度气候强迫(例如，极端、趋势、年代际变化)放大的响应，以及(目标2)从单个地球系统模式(ESM)的大集合中推断的人为气候变化的预计变化，这些模式能够区分内部和强迫可变性。两名女性博士生将接受培训和指导。PI将在他正在进行的加州LTER、PICES和US CLIVAR的跨学科研究/领导活动中分享这项研究。这项研究产生的高分辨率区域气候总体档案将是东北太平洋海洋研究界的独特财富。PI将与CCE-LTER团队合作，使模型输出可用于跨学科研究，并开发一套线性逆模型教程，以帮助海洋生态系统科学家应用这种方法来探索生态动力学。调查的任务将包括(T1)10个成员的高分辨率区域海洋-大气耦合模式历史模拟东北太平洋(1950-2019年)和一个被动示踪物输送模块，以缩小大尺度太平洋气候强迫对Goa和CCS区域输送动力学的影响，(T2)一套线性逆模式(LIM)，以确定和量化大尺度驱动因素对从被动示踪剂推断的与生态相关的区域输送统计数据的影响，(T3)使用单个ESM的大型集合模拟(例如CESM，GFDL ESM2M)作为对LIM的输入，在SSP5-8.5或同等情景下，以调查在内部气候变化的背景下，人为强迫预计如何影响目标运输统计数据。最近东北太平洋气候变化和生态系统同步性加剧，加上2013-15年东北太平洋海洋热浪、2015-16年厄尔尼诺强厄尔尼诺和2019年阿拉斯加热浪的极端温度对生态和社会的影响，引起了对自然和人为强迫在东北太平洋区域海洋学中的作用的关切和问题。长期以来，涡旋尺度的输送动力学(如近岸、跨岸、上升流)一直被认为是海洋生态系统变化的关键驱动因素，但这些动力学对气候变化的反应尚不清楚。这项工作将提供关于生态驱动因素气候变化的最新趋势如何与长期历史变化和人为力量相关的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Over the last decades, the Northeast Pacific (NEP), has experienced dramatic changes in its climate with the occurrence of a sequence of record-breaking temperature extremes between 2013-2019, such as the multi-year 2013-15 Northeast Pacific marine heatwave, the strong 2015-16 El Niño, and more recently the ongoing 2019 Alaskan heatwave. The resulting changes in temperature and eddy-scale ocean transport dynamics (e.g. cross-shore, alongshore, upwelling) in the Gulf of Alaska (GOA) and California Current System (CCS) led to dramatic ecosystem impacts that include harmful algal blooms along the coasts, low primary productivity, massive die offs of mammals and birds. Despite advances in our understanding of the large-scale Pacific changes, it remains unclear how regional transport dynamics of the GOA and CCS are responding to the observed climate extremes and trends in decadal climate variability in the NEP, and what changes in transport statistics are expected under anthropogenic climate forcing. Key Questions: (Q1) How did the amplification of the regional climate variance in the Northeast Pacific over the last decades impact eddy-scale transport dynamics (e.g. alongshore, cross-shore, upwelling) in the California and Gulf of Alaska circulation systems? (Q2) What are the Pacific largescale drivers that control the regional ocean transport statistics during the recent temperature extremes (2013-2019), and are the changes in transport significant (e.g. an extreme) in the context of historical long-term variability (1950-2000)? (Q3) How are ecologically-relevant transport statistics in the Northeast Pacific expected to change under anthropogenic forcing (2050-2100), and are these changes consistent with what occurred during the recent extremes (2013-2019)? The goal of this research is to identify and estimate the response of ecologically-relevant eddyscale transport dynamics in the Northeast Pacific to (GOAL1) recent amplifications of large-scale climate forcing (e.g. extremes, trends, decadal variability), and (GOAL2) projected changes in anthropogenic climate change as inferred from large-ensemble of individual Earth System Models (ESMs) that allow to separate the internal vs forced variability. Two female Ph.D. students will be trained and mentored. The PI will share this research in his ongoing interdisciplinary research/leadership activities in the California-LTER, PICES, and US CLIVAR. The high-resolution regional climate ensemble archive generated in this study will be a unique asset to the marine research community in the Northeast Pacific. The PI will work with the CCE-LTER team to make the model output available for interdisciplinary studies and to develop a set of Linear Inverse Model tutorials to help marine ecosystem scientists apply this methodology to explore ecological dynamics.The approaches & TASKs of the investigation will include (T1) a 10-member ensemble of high-resolution regional coupled ocean-atmosphere model historical simulations of the Northeast Pacific (1950-2019) with a passive tracers transport module to downscale the impact of large-scale Pacific climate forcing on regional transport dynamics in the GOA and CCS, (T2) a set of Linear Inverse Models (LIMs) to identify and quantify the effects of large-scale drivers on ecologically-relevant regional transport statistics inferred from the passive tracers, (T3) the use of large ensemble simulations of individual ESMs (e.g. CESM, GFDL ESM2M) under the SSP5-8.5 or equivalent scenario as input to the LIM to investigate how anthropogenic forcing is projected to impact the targeted transport statistics in the context of internal climate variability. The recent increase in climate variance and ecosystem synchrony in the Northeast Pacific, together with the ecological and societal impacts of the temperatures extremes of the 2013-15 Northeast Pacific marine heatwave, the strong 2015-16 El Niño, 2019 Alaskan heatwave, raise concern and questions of the role of natural and anthropogenic forcing in the regional oceanography of the Northeast Pacific. Eddy-scale transport dynamics (e.g. alongshore, cross-shore, upwelling) have long been recognized as a key driver of marine ecosystem change, yet the response of these dynamics to a changing climate remains unclear. This work will provide understanding on how the recent trends in the climate variance of ecological drivers relates to long-term historical variability and to anthropogenic forcing.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.