Collaborative Research: P2C2--Assimilation of Cool and Warm Season Moisture Reconstructions and Atmospheric Conditions Over North America for the Past Millennium

合作研究：P2C2——过去千年北美冷暖季水分重建和大气条件的同化

• 批准号: 1702423
• 负责人: Gregory Hakim
• 金额: $ 14.51万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-15 至 2021-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1702423&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Assimilation; Cool

Droughts and floods have had a major impact on the economy and ecosystems in the United States (US) during the instrumental period. All of these hydroclimate extremes exhibited noticeable seasonal variability, suggesting that the seasonality is an important component of variability and forcing behind drought and wetness regimes. There is robust evidence from paleoclimate records that the U.S. was struck by more intense, long lasting, and widespread drought and wet episodes during the last two thousand years. However, many of the available proxy records cannot resolve the seasonality of droughts and pluvials. Therefore, the discrete seasonality of hydroclimate variations needs to be specified in proxy reconstructions to the extent possible to provide the most realistic estimation of past climate. The research outlined in this project is a plan to estimate discrete cool and warm season surface moisture and associated atmospheric states on an annual basis over North America during the last millennium using an offline data assimilation approach. These new estimations will then be used to understand the atmospheric circulation and large-scale forcing of cool and warm season droughts and pluvials on interannual, decadal, and centennial time scales.The research will reconstruct gridded cool and warm season moisture and three dimensional atmospheric states across North America during the last millennium using paleoclimate data assimilation (PDA) techniques. The explicit seasonal reconstructions will be based on the North American Seasonal Drought Atlas (NASDA) and a subset of existing annual tree ring chronologies with restricted seasonal climate responses. The paleoclimate data assimilation uses dynamical models to infer spatial relationships within and between climate fields. Therefore, the estimated seasonal moisture and atmospheric states are physically and dynamically consistent. The cool and warm season moisture and atmospheric states will all be exactly dated and annually resolved. The new reconstructions will provide an unprecedented opportunity to quantify the cross-season coherency and casual mechanisms of major drought and pluvial events during the last millennium. This project will examine whether the physical processes that initiated, sustained and/or diminished past droughts or pluvials in North America could vary at different time scales. Specifically, the new reconstructions will be used to test hypotheses concerning: 1) the ocean-atmospheric forcing of cool and warm season hydroclimate over North America, 2) the climate dynamics responsible for persistent droughts and pluvials on seasonal basis, 3) the linkages between cool and warm season hydroclimate variability, and 4) the causal mechanisms for individual hydroclimate extremes.The potential Broader Impacts (B.I.) include the development of an online and interactive atlas of cool and warm season moisture and atmospheric states for each year over the past millennium. This atlas will include maps of cool and warm season moisture, sea level pressure, 500hPa geopotential height and other key variables. Users from academic communities and the general public will be able to access the detailed seasonal atmospheric information for any particular year or group of years. The seasonal reconstructions will also provide an objective framework to evaluate the impacts of hydroclimate extremes on social and ecological changes during the prehistoric, colonial, and modern eras. The researchers will collaborate with the Arkansas State Climate Office to promote the awareness of potential water issues associated with droughts and pluvials. This project will also support one graduate studentThis 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.

在工具时期，干旱和洪水对美国（美国）的经济和生态系统产生了重大影响。所有这些氢气候极端都表现出明显的季节性变异性，这表明季节性是变异性的重要组成部分，并在干旱和潮湿方案背后强迫。古气候记录中有强有力的证据表明，在过去的两千年中，美国被更激烈，持久和广泛的干旱和潮湿的发作所震惊。 但是，许多可用的代理记录无法解决干旱和pluvials的季节性。因此，需要在代理重建中指定氢气气候变化的离散季节性，以提供对过去气候的最现实估计的可能程度。 该项目中概述的研究是一项计划，旨在使用离线数据同化方法在上一千年期间，在北美估算北美的离散凉爽和温暖的季节水分和相关的大气状态。然后，这些新的估计将用于了解大气循环和大规模强迫凉爽和温暖的季节干旱和对年龄段，十年和百年纪念的时间尺度上的大气循环。该研究将在上一千千年中使用古气候数据（PDA）技术（PDA）技术来重建北美三维大气层的凉爽和温暖的季节水分和三维大气层。明确的季节性重建将基于北美季节性干旱地图集（NASDA），以及现有的年度树环的子集，并具有受季节性气候反应的受限。古气候数据同化使用动力学模型来推断气候领域内和之间的空间关系。因此，估计的季节性水分和大气状态在身体和动态上是一致的。凉爽和温暖的季节水分和大气状态都将过时并每年解决。新的重建将为上一个千年期间重大干旱和pluvial事件的跨季节连贯性和休闲机制提供前所未有的机会。该项目将检查北美过去，持续和/或减少过去的干旱或普卢维亚群落的物理过程在不同的时间范围内是否会有所不同。具体而言，新的重建将用于测试有关的假设：1）北美凉爽和温暖的季节氢化气候的海洋 - 大气强迫，2）季节性的持续干旱和季节性的气候动态，3）3）凉爽和温暖的季节性氢化液体之间的联系，以及4）跨越的季节性综合机制，以及4）造成的杂物（4）Caus B.（4）Caus B. implime for Caus B.（4）包括在过去的千年中开发一个凉爽和温暖的季节水分和大气状态的在线和互动地图集。 该地图集将包括凉爽和温暖的季节水分，海平面压力，500HPA地球电位高度和其他关键变量的地图。 来自学术社区和公众的用户将能够在任何特定年度或群体中访问详细的季节性大气信息。季节性的重建还将提供一个客观的框架，以评估史前，殖民地和现代时代期间氢化气候极端对社会和生态变化的影响。 研究人员将与阿肯色州国家气候局合作，以提高人们对与干旱和pluvials相关的潜在水问题的认识。 该项目还将支持一个研究生这一研究生奖，这反映了NSF的法定任务，并被认为是使用基金会的知识分子优点和更广泛影响的评论标准的评估值得支持的。

项目成果

Local Regions Associated With Interdecadal Global Temperature Variability in the Last Millennium Reanalysis and CMIP5 Models

• DOI: 10.1029/2019jd030426
• 发表时间: 2019-09
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: L. Parsons;G. Hakim

Do Multi‐Model Ensembles Improve Reconstruction Skill in Paleoclimate Data Assimilation?

• DOI: 10.1029/2020ea001467
• 发表时间: 2021-03
• 期刊: Earth and Space Science
• 影响因子: 3.1
• 作者: L. Parsons;D. Amrhein;S. Sanchez;R. Tardif;M. K. Brennan;G. Hakim

Coupled Atmosphere–Ocean Reconstruction of the Last Millennium Using Online Data Assimilation

• DOI: 10.1029/2020pa003959
• 发表时间: 2021-03
• 期刊: Paleoceanography and Paleoclimatology
• 影响因子: 3.5
• 作者: W. Perkins;G. Hakim

Climate Model Teleconnection Patterns Govern the Niño-3.4 Response to Early Nineteenth-Century Volcanism in Coral-Based Data Assimilation Reconstructions

气候模型遥相关模式控制 Niño-3.4 对基于珊瑚的数据同化重建中十九世纪早期火山活动的响应

• DOI: 10.1175/jcli-d-20-0549.1
• 发表时间: 2021
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: Sanchez, Sara C.;Hakim, Gregory J.;Saenger, Casey P.
• 通讯作者: Saenger, Casey P.

Last Millennium Reanalysis with an expanded proxy database and seasonal proxy modeling

• DOI: 10.5194/cp-15-1251-2019
• 发表时间: 2018-09
• 期刊: Climate of the Past
• 影响因子: 4.3
• 作者: R. Tardif;G. Hakim;W. Perkins;K. Horlick;M. Erb;J. Emile‐Geay;D. Anderson;E. Steig;D. Noone