Collaborative Research: Tropical Cyclones in a Warming Climate: Lessons from Model Simulations of the Last Glacial Maximum and Holocene

这个合作项目使用数值模拟来研究热带气旋（TC，包括大西洋飓风，太平洋台风和印度洋的cycones）在最后一个冰河时代（约21，000年前）的高度和大约6，000年前的全新世中期温暖时期的可能行为。人们非常关注了解近几十年来世界海洋变暖对热带气旋的影响以及热带气旋对未来全球变暖的可能反应。本研究旨在通过回顾过去的气候来进一步了解气候变化对TC的影响，这些气候与今天的气候有很大的不同，尽管方式不同。本文提出了四个具体问题：1）在末次盛冰期和中全新世强迫作用下，影响热带气旋生成的因子如何变化？2)不同的模型如何解决这些大尺度因素是否存在显著差异？哪些变化似乎可归因于模式的变异性，哪些变化可归因于外部强迫的变化？3)与工业化前或现在的条件相比，在气候模型中发现的TC样涡旋在末次盛冰期和全新世中期的模拟中是如何变化的？4)一个更高分辨率的区域模式对古气候环境的模拟是如何处理成因的？随着气候强迫的变化，风暴数量和路径密度是如何变化的？这项研究是基于初步结果，发现证据表明，尽管全球海洋表面温度普遍较低，但上一个冰河时代的气候可能对某些地区的TC发展相对有利。这项工作在科学界产生了更广泛的影响，因为它将为新兴科学“古风暴学”的研究提供信息，这是对过去气候中TC和其他风暴行为的跨学科研究。这项工作还将为了解全球变暖对登陆TC的影响提供信息，包括沿着美国海岸线的飓风。此外，这项工作将资助和培训一名研究生和一名博士后研究人员，从而为下一代科学家提供支持和培训。

This collaborative project uses numerical simulations to study the likely behavior of tropical cyclones (TCs, which include Atlantic hurricanes, Pacific typhoons, and cycones in the Indian Ocean), at the height of the last ice age (about 21,000 years ago) and during the mid-holocene warm period of about 6,000 years ago. Much attention has been devoted to understanding the impact on TCs of the warming of the world's oceans over recent decades and the likely response of TCs to future global warming. This study seeks to further understanding of the impact of climate change on TCs by looking backward to past climates which are comparably different from today's climate, although in different ways. Four specific questions are addressed: 1) How do the factors that influence tropical cyclone genesis vary under LGM and mid-holocene forcings? 2) Are there significant variations in how different models resolve these large-scale factors? Which changes appear attributable to model variability and which to variations in external forcing? 3) How do the TC-like vortices found in climate models change in LGM and mid-holocene simulations when compared to preindustrial or present-day conditions? 4) How does a higher resolution, regional model's simulation of a paleoclimate environment handle genesis? How do storm counts and track densities vary as the climate forcing changes? The research is based on preliminary results which find evidence that the climate of the last ice age may have been relatively favorable for TC development in some regions, despite the generally colder sea surface temperatures worldwide. The work has broader impacts in the scientific community as it will inform research into the emerging science of "paleotempestology", the interdisciplinary study of the behavior of TCs and other storms in past climates. The work will also inform efforts to understand the impact of global warming on landfalling TCs including hurricanes along the US coastline. In addition, the work will fund and train a graduate student and a postdoctoral researchers, thereby providing support and training for the next generation of scientists.