Synoptic Control of Mesoscale Precipitating Systems in the Pacific Northwest

这项研究将考察在天气尺度上对气流特征的适当表示在多大程度上允许熟练地模拟中尺度降水系统。这项研究将强调在受控环境下的独立验证和严格的假设检验，以量化结果的重要性。研究的重点是美国西海岸登陆降水系统的具体问题。首席调查员将探索导致该地区显著降雨的各种登陆系统。研究的主要工具将是高级中尺度数值模式、NCEP和ECMWF再分析数据集，以及太平洋沿岸各州(华盛顿州、俄勒冈州和加利福尼亚州)所有可用地面站点的独立降水量测量。横向边界条件(LBC)的作用将在研究设计中明确说明，研究结果的持续评估将用于控制可能由模式物理限制引入的偏差。分离初始和边界条件误差、嵌套网格模式边界位置引起的LBC误差以及按天气系统类型划分的误差将代表着对这些天气系统的理解的重大进步。这项研究的结果将对短期天气预报有相当大的兴趣。

This research will examine the extent to which an adequate representation of flow features on the synoptic scale allows for the skillful simulation of mesoscale precipitating systems. The research will emphasize independent verification and rigorous hypothesis testing within a controlled setting in order to quantify the significance of the results. The focus of the research is on the specific problem of landfalling precipitating systems on the West Coast of United States. The Principal Investigators will explore a broad variety of landfalling systems that lead to significant rainfall in this region. The primary tools of the research will be an advanced mesoscale numerical model, NCEP and ECMWF reanalysis data sets, and independent precipitation measurements from all available surface sites in the Pacific coast states (Washington, Oregon and California). The role of lateral boundary conditions (LBC) will be explicitly accounted for by the study design and ongoing evaluation of study results will be used to control for biases that may be introduced by model physics limitations.Separating initial and boundary condition errors, LBC errors due to the placement of the boundaries of the nested grid model, and error by type of synoptic system will represent a significant advance in understanding of these weather systems. The results of this study will be of considerable interest to short term weather forecasting.