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: 0852459
• 负责人: Sergey Kravtsov
• 金额: $ 30.23万
• 依托单位: University of Wisconsin-Milwaukee
• 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 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0852459&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年美国复苏和再投资法案（公法111-5）资助的。低频大气变率，时间尺度从一周到几个月，将通过确定少数持续时间比大多数其他国家的流动状态进行研究。这种状态被广泛地称为流动状态。这些制度对中期预报很重要，因为其持久性的提高可能转化为可预测性的增强。它们被认为是由于在地形（太平洋和大西洋纬向/阻塞流型）存在下行星波/纬向平均流相互作用，或快速天气涡旋的低频组织及其随后对大尺度流的反馈（与环形模式相关的流型）而产生的。理论证据表明，上述两种制度类型具有不同的空间格局和持久性特征;据推测，第一种类型的制度往往是更多的地理局限性，比第二种类型的制度更不持久。它进一步证实，动力学过程，驱动两种类型的制度很可能是一致的，导致混合制度类型，如北大西洋涛动。这些假设将使用观测分析，理论建模和大气环流模型（GCM）实验的组合进行探索。一种新的技术，这是从调查人员以前的工作中出现的，将被用来隔离制度的观测北方半球的大气流动，定义为情节的流序列，线性统计预测有一个异常低的技能;这些计算将进行二维，以及纬向平均场。一套长的模拟理想化，准地转，斜压模式，和非物理学大气环流模式将执行和分析范围广泛的参数。额外的实验将包括政权情节和模拟的案例研究进行手术切除潜在的重要相互作用，这些分析将阐明负责政权behavior.The更广泛的影响，这项研究涉及到社会意义的问题，中期和长期的天气预报。该项目将加强两个机构之间的科学伙伴关系，并进一步编制大气动力学和统计方法方面的研究生课程和培训。