Processes Linking Easterly Waves and the North American Monsoon System

本研究将讨论与东风波和热带扰动有关的北美季风的变化。将使用一个区域模式的25年以上的观测和短期预报。以前的研究表明，东风波和热带风暴对北美季风区降水的位置和数量有重大影响。北美季风的几个关键过程在全球或区域模式中没有得到很好的体现，因此很难建立将季风天气变率与热带海洋-大气系统相关的更缓慢变化过程联系起来的物理机制。研究人员将使用短期天气研究与预报（WRF）模型模拟来确定东风波浪和热带扰动如何影响季风降水。该模式将以足够高的分辨率运行，以避免在核心季风区使用对流参数化，从而消除区域模式模拟季风降水误差的主要因素之一。这项工作具有改善季风预报的潜力，它解决了北美季风实验（NAME）的科学目标，这是2004年夏天进行的一项实地活动，目的是确定季风降水的来源和可预测性的限制。这项研究建立在NAME社区的工作基础上，包括两位主要研究者（PI）的工作，以及最近关于东风波的工作，包括第三位PI的工作。在建模方面，本研究利用了亚利桑那大学WRF模式，该模式提供了西南地区最高分辨率的预报，为西南地区新兴研究应用和社会需求的区域大气模式的建立做出了贡献。该项目的更广泛影响包括可能改善季风预报，帮助西南地区的地方政府应对洪水和与天气有关的灾害，并为其不断增长的人口管理水资源。该项目将促进亚利桑那大学校园内的多学科互动，包括开发一个新的水文气象学项目；它将支持本科科学研究，向学生提供西班牙裔和女性科学家在物理科学方面取得成就的例子，并提供这些科学家的指导。研究生和一个或多个本科研究项目将得到支持。

This study will address variability in the North American monsoon associated with easterly waves and tropical disturbances. More than 25 years of observations and short-term forecasts from a regional model will be used. Previous work suggests that easterly waves and tropical storms have a significant influence on the location and amount of precipitation within the North American monsoon region.Several key processes of the North American monsoon are not well represented in global or regional models, making it difficult to establish the physical mechanisms linking monsoon synoptic variability with more slowly varying processes associated with the tropical ocean-atmosphere system. The investigators will use short-term Weather Research and Forecasting (WRF) model simulations to determine how easterly waves and tropical disturbances affect monsoon precipitation. The model will be run at high enough resolution to avoid the use of convective parameterizations in the core monsoon region, thus eliminating one of the primary contributors to errors in regional model simulations of monsoon precipitation.This work has the potential for improving monsoon forecasts and it addresses the scientific objectives of the North American Monsoon Experiment (NAME), a field campaign that took place in the summer of 2004 with the goals of determining the sources and limits of predictability of monsoon precipitation. This study builds on the work of the NAME community, including that of two of the principal investigators (PIs), as well as recent work on easterly waves including that of the third PI. The modeling aspect of the proposed study takes advantage of the University of Arizona WRF model, the model providing the highest resolution forecasts of the Southwest, and it will contribute to the establishment of a regional atmospheric model for emerging research applications and societal needs in the Southwest region.Broader impacts of this project include potential improvements in monsoon forecasts that can help local governments in the Southwest to respond to flooding and weather-related hazards and to manage water resources for their growing populations. The project will contribute to multidisciplinary interactions on the University of Arizona campus, including the development of a new hydrometeorology program; it will support undergraduate research in the sciences and provide students with examples of the achievements of Hispanic and women scientists in a physical science and mentoring from such scientists. A graduate student and one or more undergraduate research projects will be supported.