Sub-Daily Scale Extreme Precipitation in Future Climate-Change Scenarios: A Pilot Study

未来气候变化情景中的次日尺度极端降水：试点研究

• 批准号: 0541491
• 负责人: Robert Trapp
• 金额: --
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0541491&HistoricalAwards=false
• 关键词: Sub; Daily; Scale; Extreme; Precipitation

Sub-daily extreme rainfall events and their associated convective precipitating systems will be explicitly simulated over North America by employing a hierarchical, scale-spanning modeling approach that culminates in 3D cloud resolving model simulations. The experimental design consists of global climate model (GCM), nested regional climate model (RCM), and sub-nested cloud-resolving model (CRM) integrations. The PIs will employ two basic approaches: GCM-CRM nesting and GCM-RCM-CRM nesting. This is the first attempt to simulate historical severe convective weather events over the contiguous United States using these two approaches. The case study events will include the tornado super-outbreak of 3 April 1974, the flash flood and hailstorm event of 5 May 1995, and others as deemed necessary. The majority of the work "to include the analysis and verification of the events, as well as their use in the development of the statistical tools" will be devoted to these retrospective experiments. However, once the optimum method for has been established, the PIs will perform an initial experiment forced by an IPCC SRES emissions scenario to examine the ability of that method to simulate the response of sub-daily extreme rainfall events to enhanced greenhouse forcing. The primary objectives are: 1. To identify the optimum methodology for one-way coupling of a GCM, a nested RCM and a sub-nested CRM by simulating historical events using a range of configurations and comparing the various simulations against instrumental data. 2. To yield an initial projection of the characteristics, frequency, and geographical distribution of sub-daily extreme rainfall events for a future emissions scenario, by comparing the simulated future events to similar historical events. 3. To yield an initial projection of where and when the sub-daily extreme rainfall will be accompanied by other hazardous weather phenomena such as tornadoes and hail, by associating the future events with specific types of precipitating weather systems and hence with the most likely attendant hazardous phenomena. The broader impacts of the project include the education and training of two graduate students. If this pilot project is successful, it will demonstrate the potential for projecting statistics of severe weather events in a climate forced by human activities. Information from such projections could be of significant benefit to policy makers.

通过采用分层、跨尺度的建模方法，将在北美上空显式地模拟次日极端降雨事件及其相关的对流降水系统，最终形成3D云解析模式模拟。试验设计包括全球气候模式(GCM)、嵌套区域气候模式(RCM)和次嵌套云分辨模式(CRM)集成。PIS将采用两种基本方法：GCM-CRM嵌套和GCM-RCM-CRM嵌套。这是首次尝试使用这两种方法模拟美国毗邻地区的历史强对流天气事件。个案研究活动将包括1974年4月3日的龙卷风大爆发、1995年5月5日的山洪暴发和冰雹事件，以及认为必要的其他事件。大部分工作“包括对事件的分析和核查，以及在开发统计工具时的使用”，将专门用于这些回溯性实验。然而，一旦确定了最佳的方法，PIS将执行一项由IPCC SRES排放情景强制进行的初步实验，以检验该方法模拟次日极端降雨事件对增强的温室强迫的反应的能力。主要目标是：1.通过使用一系列配置模拟历史事件并将各种模拟与仪器数据进行比较，确定用于GCM、嵌套RCM和子嵌套CRM的单向耦合的最佳方法。2.通过将模拟的未来事件与类似的历史事件进行比较，初步预测未来排放情景下次日极端降雨事件的特征、频率和地理分布。3.初步预测次日极端降雨将在何时何地伴随龙卷风和冰雹等其他危险天气现象，将未来事件与特定类型的降水天气系统联系起来，从而与最有可能伴随的危险现象联系起来。该项目的更广泛影响包括教育和培训两名研究生。如果这一试点项目成功，它将展示在人类活动强迫的气候中预测恶劣天气事件统计数据的潜力。来自这些预测的信息可能会对政策制定者产生重大好处。