NSFGEO-NERC: Large-Scale Atmospheric Circulation Response to Oyashio Extension Frontal Variability

NSFGEO-NERC：大规模大气环流对 Oyashio 扩展锋面变化的响应

• 批准号: 2040073
• 负责人: Young-Oh Kwon
• 金额: $ 86.03万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2040073&HistoricalAwards=false
• 关键词: NSFGEO; NERC; Large; Scale; Atmospheric

Winter over the North Pacific features an endless parade of frontal storms, forming near Japan and building as they cross the ocean to reach North America. Model simulations can produce realistic North Pacific storms even if the sea surface temperatures (SSTs) are held fixed, indicating that the storms owe their existence to the strong upper-level jet stream and accompanying north-south atmopsheric temperature contrast rather than air-sea interactions. Nevertheless there are intriguing hints that storm behavior can be influenced by variations in the underlying SSTs, and some indications that slowly varying SSTs may change storm paths and behavior in ways that could prove useful for making long-range weather predictions. The SST variations of interest occur as a result of the meandering of the Kuroshio-Oyashio Extension (KOE), a narrow ocean current that extends into the Pacific from the coast of Japan. The KOE is a warm current and the sharp temperature contrast between the current and the cold water north of it produces relatively strong SST variations when the KOE shifts to the north or south.Attempts to identify and analyze the influence of KOE-related SST variations on storms and atmospheric circulation have had mixed results. But recent work by the Principal Investigators (PIs) and others suggests that the key to capturing the atmospheric response is to dramatically increase the resolution of atmospheric models used for this purpose. In particular the PIs have developed a variable resolution version of the Community Atmosphere Model version 6 (VR-CAM6) which takes advantage of the spectral element dynamical core to increase resolution over the North Pacific (a box from 20N to 60N and 130E to 110W). The lower resolution outside the North Pacific allows the model to be run cheaply enough to allow large ensembles of simulations, with 60 or more separate simulations for each imposed SST anomaly pattern, so that even weak atmospheric responses can be captured and analyzed.A further asset in identifying the atmospheric response to KOE-related SST variations is a simplified ocean model which allows the near-surface ocean to respond to changes in surface winds and other atmospheric forcing. The model is referred to as a "pencil" ocean model, or PenOM, because it represents the up and down transfer of heat in a column of the ocean below each grid box of the surface atmosphere. PenOM does not simulate the lateral movement of water in ocean currents, but work under this award adds the capability to represent changes in SST due to Ekman transport, meaning the sideways drift caused by the Coriolis force acting on water pushed along by the surface wind.The work is of societal as well as scientific interest due to its relevance to long-term weather prediction as noted above. Also, the PenOM configuration with Ekman transport will be made available to the worldwide research community through the Community Earth System Model as part of its suite of simpler model configurations. The work promotes international collaboration in atmospheric research through its collaboration with Dr. Arnaud Czaja at Imperial College London, through the arrangement noted below. Also, the project supports several outreach activities including the production of a short educational video featuring model simulations and research results. The project also provides support and training to a postdoctoral research associate.This project is jointly funded by the National Science Foundation’s Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. The Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with its own country.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.

北太平洋的冬季以无休止的锋面风暴游行为特色，它们在日本附近形成，并在穿越海洋到达北美时形成。 模式模拟可以产生现实的北太平洋风暴，即使海表温度（SST）是固定的，这表明风暴的存在归功于强大的上层急流和伴随的南北大气温度对比，而不是海气相互作用。 然而，有一些有趣的暗示表明，风暴的行为可能会受到底层SST变化的影响，并且一些迹象表明，缓慢变化的SST可能会改变风暴的路径和行为，这些方式可能被证明对长期天气预报有用。感兴趣的SST变化发生的黑潮-俄亥俄延伸（KOE），从日本海岸延伸到太平洋的狭窄洋流的弯曲的结果。KOE是一股暖流，当KOE向北或向南移动时，其北部冷水与暖流之间的强烈温差会产生相对较强的SST变化，试图识别和分析与KOE相关的SST变化对风暴和大气环流的影响，结果喜忧参半。 但是，主要研究人员（PI）和其他人最近的工作表明，捕捉大气响应的关键是大幅提高用于此目的的大气模型的分辨率。特别是，研究所开发了一个可变分辨率版本的共同体大气模式第6版（VR-CAM 6），该版本利用光谱要素动力核心来提高北太平洋的分辨率（从北纬20度到60度，东经130度到西经110度的方框）。北太平洋以外较低的分辨率使模式能够以足够低的成本运行，以允许大规模的模拟，对每个强加的SST异常模式进行60个或更多的单独模拟，因此，即使是微弱的大气响应也可以被捕获和分析。识别大气对KOE相关SST变化的响应的另一个资产是一个简化的海洋模式，它允许近-海洋表面对表面风和其他大气强迫的变化作出反应。 该模型被称为“铅笔”海洋模型，或PenOM，因为它代表了海洋柱中的热量上下传递，低于表面大气的每个网格框。 PenOM并不模拟洋流中水的横向运动，但在该奖项下的工作增加了表现由于埃克曼输送而引起的SST变化的能力，埃克曼输送是指由表面风推动沿着运动的科里奥利力作用于水而引起的侧向漂移。由于与上述长期天气预报相关，这项工作具有社会和科学意义。 此外，将通过共同体地球系统模型向全世界研究界提供带有埃克曼运输的PenOM配置，作为其一套较简单的模型配置的一部分。这项工作通过与伦敦帝国学院Arnaud Czaja博士的合作，通过下述安排，促进了大气研究方面的国际合作。 此外，该项目还支持开展若干外联活动，包括制作一个介绍模型模拟和研究结果的教育短片。 该项目由美国国家科学基金会地球科学理事会（NSF/GEO）和英国国家环境研究理事会（NERC）通过NSF/GEO-NERC牵头机构协议共同资助。该协议允许美国/英国提交一份联合提案，并由其研究人员拥有最大比例预算的机构进行同行评审。一旦成功地共同确定了一个奖项，每个机构都会资助与其本国有关的预算和调查人员的比例。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。

项目成果

On the Statistical Estimation of Asymmetrical Relationship Between Two Climate Variables

• DOI: 10.1029/2022gl100777
• 发表时间: 2022-10-28
• 期刊: GEOPHYSICAL RESEARCH LETTERS
• 影响因子: 5.2
• 作者: Frankignoul, Claude;Kwon, Young-Oh
• 通讯作者: Kwon, Young-Oh

Multidecadal Regime Shifts in North Pacific Subtropical Mode Water Formation in a Coupled Atmosphere‐Ocean‐Sea Ice Model

耦合大气-海洋-海冰模型中北太平洋副热带模式水形成的多年代际变化

• DOI: 10.1029/2022gl099406
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Kim, Sang‐Yeob;Kwon, Young‐Oh;Park, Wonsun;Lee, Ho Jin
• 通讯作者: Lee, Ho Jin