Collaborative Research: Study of the Relationship between Regionally Localized and Zonally Symmetric Anomalously Persistent Weather States

合作研究：区域局域性和纬向对称异常持续天气状态之间的关系研究

• 批准号: 0852379
• 负责人: Steven Feldstein
• 金额: $ 9.19万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0852379&HistoricalAwards=false
• 关键词: Collaborative; Research; Study; Relationship; between

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Low-frequency atmospheric variability, with time scales from one week to a few months, will be studied by identifying a small number of flow states that persist longer than most other states. Such states are widely referred to as flow regimes. The regimes are important for medium-range forecasting since their elevated persistence may translate into enhanced predictability. They are thought to arise due to planetary wave/zonal mean flow interaction in the presence of topography (Pacific and Atlantic zonal/blocked flow regimes), or low-frequency organization of the fast synoptic eddies and their subsequent feedback onto the large-scale flow (regimes associated with annular modes). Theoretical evidence suggests that the above two regime types have different spatial patterns and persistence characteristics; it is hypothesized that the regimes of the first type tend to be more geographically confined, and less persistent than the regimes of the second type. It is further conjectured that dynamical processes that drive the two types of regimes are likely to coincide, resulting in mixed regime types such as the North Atlantic Oscillation. These hypotheses will be explored using a combination of observational analyses, theoretical modeling, and General Circulation Model (GCM) experiments. A new technique, which emerged from the investigators' previous work, will be used to isolate regimes in the observations of the Northern Hemisphere's atmospheric flow by, defining them as the episodes of flow sequences for which linear statistical forecasts have an abnormally low skill; these calculations will be performed for two-dimensional, as well as for the zonally averaged fields. A set of long simulations of idealized, quasi-geostrophic, baroclinic models, and simplified-physics general circulation models will be performed and analyzed for a wide range of parameters. Additional experiments will include case studies of regime episodes and simulations subjected to surgical removal of potentially important interactions; these analyses will elucidate processes responsible for regime behavior.The broader impacts of this study relate to the societal significance of the problem of medium- and long-range weather forecasting. The project will strengthen scientific partnerships between the two institutions and further the development of graduate curricula and training in atmospheric dynamics and statistical methods.

该奖项是根据2009年的《美国回收与再投资法》（公法111-5）进行的。低频率大气变异性，随着时间尺度从一周到几个月，将通过确定比大多数其他州更长的流量状态来研究。这样的状态被广泛称为流程。这些制度对于中等预测很重要，因为它们的持久性升高可能会转化为增强的可预测性。人们认为它们是由于地形（太平洋和大西洋地区和大西洋地区/阻塞流程度）或快速天气涡流的低频组织以及随后对大规模流动（与Annular Modes相关的政权）的反馈的低频组织，因此被认为是由于行星波/区域平均流动相互作用而引起的。理论证据表明，以上两种政权类型具有不同的空间模式和持久特征。假设第一种类型的制度在地理上更加限制，而持续的却不是第二类的持久性。进一步推测，驱动两种类型的制度的动力学过程可能是重合的，从而导致混合的政权类型，例如北大西洋振荡。这些假设将使用观察分析，理论建模和一般循环模型（GCM）实验的组合进行探讨。从研究人员先前的工作中产生的一种新技术将用于分离北半球大气流的观察中，将它们定义为线性统计预测的流动序列发作，其技能异常低；这些计算将用于二维以及划分平均场。将对广泛的参数进行一系列理想化的，准地斜斜模型和简化的通用循环模型的长期模拟。其他实验将包括对经手术去除潜在重要相互作用的制度发作和模拟的案例研究；这些分析将阐明负责政权行为的过程。这项研究的更广泛影响与中等和远程天气预测问题的社会意义有关。该项目将加强两个机构之间的科学伙伴关系，并进一步发展研究生课程以及大气动态和统计方法的培训。