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上的Cycones)在最后一个冰河时代(约21,000年前)和大约6000年前的中全新世暖期期间的可能行为。人们一直致力于了解近几十年来世界海洋变暖对海洋气候变化的影响，以及海洋气候变化对未来全球变暖的可能反应。这项研究试图通过回顾过去的气候来进一步了解气候变化对技术转换的影响，这些气候与今天的气候相比有很大的不同，尽管方式不同。讨论了四个具体问题：1)影响热带气旋发生的因素在大冰年和中全新世强迫下是如何变化的？2)不同的模式如何解决这些大尺度因素是否存在显著差异？哪些变化可归因于模式的可变性，哪些可归因于外部强迫的变化？3)气候模型中发现的类似TC的涡旋在末次冰期和中全新世模拟中与工业化前或现代条件相比是如何变化的？4)更高分辨率的区域模型对古气候环境的模拟如何处理成因？随着气候变化，风暴数量和路径密度是如何变化的？这项研究基于初步结果，这些结果发现有证据表明，尽管全球海洋表面温度普遍较低，但上一次冰河时代的气候可能对某些地区的热带气旋发展相对有利。这项工作在科学界产生了更广泛的影响，因为它将为“古温学”这一新兴科学的研究提供信息，这是对过去气候中TCS和其他风暴行为的跨学科研究。这项工作还将有助于了解全球变暖对登陆TC的影响，包括美国海岸线的飓风。此外，这项工作还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.