AGS-PRF: Examining the Response of Tropical Cyclone Precipitation Structure to Climate Change Using Idealized and Realistic Models

热带气旋（TC）是由旋转雷暴组成的天气系统，通常在热带地区形成，当它们在陆地上移动时可能会造成伤害，死亡和昂贵的财产损失。虽然沿海居民通常最担心TC登陆造成的洪水，但TC降水和相关的洪水可能会向内陆延伸数百英里。虽然人们已经确定，由于气候变化，TC降水率预计将在未来增加，但科学界对TC降水模式可能如何变化不太确定，这对在TC登陆之前发布最准确的洪水警报和疏散任务具有影响。该项目将探讨TC降水结构将如何受到气候变化的影响，因为结构变化可能会改变TC内的降水分布，这可能会影响洪水模式。TC降水来自内核，通常被称为眼壁，和外部雨带。更全面地了解TC在内核和外部雨带区域的降水是如何相关的，以及这两个区域的降水如何因气候变化而变化，可以帮助TC预报模型制作者根据气候变化调整他们的模型，这将反过来帮助应急管理人员和决策者在容易发生TC登陆的地区拯救生命。以前对TC降水和气候变化的模拟研究使用了粗略的-分辨率模型不能解决TC降水结构。最近使用约20年的卫星数据进行的观测研究发现，TC内核降水呈减少趋势，而TC外部雨带降水呈增加趋势，而使用数十公里或更粗网格间距的模型预测了由于气候变化导致的内核与外部雨带降水增加的冲突变化。这项研究将使用一个理想化的高分辨率模型，明确解决对流，以增加对TC内的三维降水结构如何受到大气和海洋表面温度变暖的影响的理解。结果将提供洞察观察到的趋势和气候模式预测的TC降水结构的变化之间的差异。将探讨降水结构中任何显著变化背后的物理机制。在理想化的模拟之外，在与理想化模拟相同的分辨率下运行的伪全球变暖模拟的分析将表明，理想化模拟发现的结果是否适用于地球上更多的TC。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值进行评估，更广泛的影响审查标准。

Tropical cyclones (TCs) are weather systems made up of rotating thunderstorms that usually form in the tropics and that can cause injuries, fatalities, and expensive property damage when they move over land. While coastal residents are often most concerned about flooding from TC landfalls, TC precipitation and associated flooding can extend hundreds of miles inland. Although it is well-established that TC precipitation rates are expected to increase in the future due to climate change, the scientific community is less certain about how the patterns of TC precipitation may change, which has implications for issuing the most accurate flood warnings and evacuation mandates ahead of TC landfalls. This project will explore how TC precipitation structure will be impacted by climate change since structural changes may shift the distribution of precipitation within TCs, which could impact flooding patterns. TC precipitation comes from both the inner core, commonly known as the eye wall, and outer rainbands. A more complete understanding of how TC precipitation in the inner core and outer rainband regions is related and how precipitation may change in these two regions because of climate change can aid TC forecast modelers in adapting their models to the changing climate, which will in turn help emergency managers and decision makers save lives in areas prone to TC landfalls.Previous modeling studies on TC precipitation and climate change have used coarse-resolution models that cannot resolve TC precipitation structures. Recent observational studies using about 20 years of satellite data found a decreasing trend in TC inner core precipitation and an increasing trend in TC outer rainband precipitation, while models using grid spacings of tens of kilometers or coarser have projected conflicting changes in inner core versus outer rainband precipitation increases due to climate change. This research will use an idealized high-resolution model with explicitly-resolved convection to increase the understanding of how three-dimensional precipitation structures within TCs are impacted by atmospheric and sea surface temperature warming. Results will provide insight into discrepancies between observed trends and climate model predictions of changes in TC precipitation structure. Physical mechanisms behind any notable changes in precipitation structure will be explored. Beyond the idealized simulations, an analysis of pseudo-global warming simulations run at the same resolution as the idealized simulations will show if the results discovered with the idealized simulations apply to TCs in more Earth-like environments and how precipitation during TC landfalls may change in the future.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.