Midlatitude Storm Track Dynamics on a Cloudy Earth

温带地区的大规模风暴会优先发生在被称为风暴带的区域。在北半球，风暴路径横跨北太平洋和北大西洋，其中的风暴塑造了区域天气，例如，在太平洋西北部、美国东部和欧洲。由于风暴路径是气候系统中能量和水汽输送的主要渠道，它们对于控制全球降雨量和地表温度分布等气候特征也至关重要。最近用数值大气模式进行的观测和模拟表明，气候变化对风暴路径的各个方面进行了调制。例如，风暴路径通常在气候变暖时向极地移动，在气候变冷时向赤道移动。然而，关于风暴路径的结构和可变性以及它们对气候变化的反应的根本问题仍然没有得到回答。例如，尚不清楚是什么控制了北太平洋和北大西洋风暴路径的终点，它们观测到的低频变化依赖于什么，以及这些方面和其他方面如何应对气候变化。要回答这些问题，需要更好地了解风暴路径如何与阿留申低压等稳定天气模式相互作用，以及它们如何与一方面是风暴产物的云相互作用，另一方面通过它们的吸收/反射/发射改变风暴路径运行的环境。该项目旨在通过使用观测数据和作为计算实验室的理想化大气模型进行有针对性的实验来回答这些问题。该项目将审查负责控制风暴路径的过程，方法是使用大气模型分析观测和模拟，该大气模型在某些方面得到简化(例如，它可以简化或完全消除大陆效应)，但包含相对复杂的云表示。其目的是研究控制风暴路径结构和可变性的基本过程以及它们与云的相互作用，最终形成风暴路径动力学的理论和概念模型。这项研究将弥合最先进的综合气候模型和基本物理理解之间的差距。在该项目下开发的概念模型将为评估天气预报和气候模型提供一个框架，并将提出改进它们的方法。该项目将在亚季节和更长的时间尺度上评估并有可能提高中纬度地区主要天气灾害的可预测性，包括极端风暴、干旱和洪水。它还将培训新一代科学家，他们熟练地使用从理论到综合数值模型的各种最先进的大气和气候动力学工具。这将通过以下方式实现：直接资助一名博士后学者，在本项目结束时，他将准备好开始她在气候和大规模动力学方面的独立职业生涯；通过在他或她的研究生涯开始时为一名研究生提供部分资金；以及通过出版物、会议报告、座谈和课堂教学来传播成果。该研究项目还将通过公开本研究中使用和开发的模型的程序代码来扩大可用研究工具的范围。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Large-scale wind storms in the extratropics occur preferentially in regions known as storm tracks. In the Northern Hemisphere, storm tracks span the North Pacific and North Atlantic, and the storms in them shape the regional weather, for example, in the Pacific Northwest, the eastern United States, and Europe. Because storm tracks are the principal conduit through which energy and moisture are transported in the climate system, they are also crucially important for controlling climatic features such as the global distributions of rainfall and surface temperature. Recent observations and simulations with numerical atmosphere models have revealed that climate changes modulate various aspects of storm tracks. For example, storm tracks generally shift poleward as the climate warms and equatorward as the climate cools. However, fundamental questions about the structure and variability of storm tracks and their response to climate changes remain unanswered. For example, it is unclear what controls where storm tracks terminate over the North Pacific and North Atlantic, what their observed low-frequency variations depend on, and how these and other aspects respond to climate changes. Answering such questions requires an improved understanding of how storm tracks interact with stationary weather patterns, such as the Aleutian Low, and how they interact with clouds which on one hand are products of storms and on the other hand modify, through their absorption/reflections/emission, the environments where storm tracks operate. This project aims to answer such questions, using observational data and targeted experiments with idealized atmosphere models that serve as a computational laboratory. The project will examine the processes responsible for controlling storm tracks by analyzing observations and simulations with an atmosphere model that is simplified in some respects (e.g., it may simplify or eliminate continental effects altogether) but contains relatively sophisticated representations of clouds. The goal is study the fundamental processes controlling the structure and variability of storm tracks and their interactions clouds, culminating in theories and conceptual models of storm track dynamics. This research will bridge the gap between state-of-the-art comprehensive climate models and fundamental physical understanding. The conceptual models to be developed under this project will provide a framework for assessing weather forecasting and climate models and will suggest ways for improving them. The project will assess and potentially enhance predictability of major weather hazards in mid-latitudes, including extreme storms, droughts, and floods, on sub-seasonal and longer timescales. It will also train a new generation of scientists who are fluent in the use of the full breadth of state-of-the-art tools in atmosphere and climate dynamics, from theory to comprehensive numerical models. This will be achieved by directly funding a postdoctoral scholar, who, by the end of this project, will be ready to commence her independent career in climate and large-scale dynamics; by partially funding a graduate student at the start of his or her research career; and by disseminating results through publications, conference presentations, colloquia, and classroom teaching. The research project will also broaden the range of available research tools by making the program code of models used and developed in this research publicly available.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.