Tropical Cyclones from 400 to 40 hPa

热带气旋，也被称为飓风和台风，是巨大而危险的风暴，在地球仪周围造成重大破坏和生命损失。跟踪和估计这些风暴强度的主要方法是通过观察围绕风暴中心（或“眼睛”）的厚圆形高卷云甲板的卫星图像，也称为卷云盾。该项目将研究卷云盾中水分和冷凝物（冰和雪）的来源和预算，以及这与风暴的整体结构和强度的关系。它还将调查热带气旋及其周围最强的雷暴在多大程度上将冰输送到更高的高度，这可能是在平流层化学中发挥重要作用的水蒸气分子的来源，对臭氧层和地球气候产生影响。本计画将研究位于所有热带气旋上方的上层外流的动力过程和湿物理。这个外流包含了卫星观测到的中央卷云盾，这些卫星提供了地球仪周围所有TC的绝大多数强度估计。不定期的现场观测、机载多普勒雷达分析和越来越真实的数值模拟表明，主外流和上方和下方的补偿流入层都可能具有高度不对称的结构，并嵌入有波、动力学不稳定性和来自强烈上升气流的过冲云顶。这些过冲的上升气流也可能不可逆转地将水分注入平流层，可能在平流层的水收支中发挥着重要作用。将利用机载多普勒雷达观测、下投式探空仪测量、卫星图像和非常高分辨率的计算机模拟来更好地了解外流的三维结构，包括外流上方和下方的相邻流入层。该项目将重点关注这些环流的上下限（高度约为400 hPa（8 km）至40 hPa（22 km））的TC的结构、动力学和水分收支。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Tropical cyclones, also known as hurricanes and typhoons, are large and dangerous storms that cause significant damage and loss of life around the globe. The primary method of tracking and estimating the intensities of these storms is through viewing satellite images of the thick circular deck of high cirrus clouds that surround the center (or “eye”) of the storm, also known as the cirrus shield. This project will examine the sources and budgets of the moisture and condensate (ice and snow) in the cirrus shield and how this relates to the overall structure and intensity of the storm. It will also investigate to what extent the strongest thunderstorms in and around tropical cyclones are transporting ice to even higher altitudes, which may represent a source of water vapor molecules that play important roles in the chemistry of the stratosphere, with implications for the ozone layer and Earth’s climate. This project will investigate the dynamical processes and moist physics of the upper-level outflow that lies above all tropical cyclones (TCs). This outflow contains the central cirrus cloud shield seen by satellites that provide the vast majority of intensity estimates for all TCs around the globe. Occasional in-situ observations, airborne Doppler radar analyses, and increasingly realistic numerical simulations suggest that both the primary outflow, and also compensating inflow layers above and below, can have highly asymmetric structures, and are embedded with waves, dynamical instabilities, and overshooting cloud tops from strong updrafts. These overshooting updrafts may also be injecting moisture irreversibly into the stratosphere, possibly playing a non-trivial role in the water budget of the stratosphere. Airborne Doppler radar observations, dropsonde measurements, satellite images, and very high-resolution computer simulations will be used to better understand the three-dimensional structure of the outflow, including the adjacent inflow layers above and below the outflow. This project will focus on the structure, dynamics and moisture budgets of TCs across the lower and upper limits of these circulations, ranging from approximately 400 hPa (8 km) to 40 hPa (22 km) in altitude.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.