Cyclogenesis in a Tropical Wave Critical Layer: Vertical Structure of the "Wave Pouch" and Impacts of the Large-scale Environment

这项工作将通过进一步研究“有袋动物范例”来解决热带气旋（以及称为热带低气压的低气压和近地面气旋风模式的前期区域）的成因问题。“这一概念模型是指飓风形成的理论，其中一种类型的母体大气扰动（称为“东风波”）的平移速度与环境气流相匹配，以形成一个保护区（或所谓的“袋”），在其中保护发展中的小规模气旋环流不受不利环境条件的影响，直到进一步加强。这项研究将得到2010年NSF支持的PREDICT（热带地区云系的预萧条调查）现场活动期间收集的数据的支持，该活动涉及NSF/NCAR GV研究飞机以及NASA和NOAA提供的补充资源。这项研究将侧重于中α尺度波袋区域（水平范围为200-2000公里）内的条件，其与大尺度环境的相互作用，以及这种相互作用对最终热带气旋形成的影响。它将结合来自PREDICT实地活动的飞行高度、下投式探空仪和雷达数据，以及再分析数据、各种卫星数据集和WRF-ARW数值模式，以解决三个主要问题：1）定义明确的波袋是热带气旋发展的必要条件吗？如果是，它是如何形成的？2)为什么有些波浪表现出一个深袋不能发展成热带风暴？3)撒哈拉空气层（SAL）如何影响热带气旋，为什么有些波袋提供保护，防止干燥空气入侵，而其他人没有？这项工作的智力价值集中在重点预测数据集的开发与数值模式模拟中进行的有袋动物的框架，导致更好地了解热带气旋。这项研究的更广泛的影响包括两名研究生的教育和培训，以及将工具和产品整合到课堂学习活动中，以及为来自代表性不足的群体的调查员提供支持。对热带气旋形成的了解增加，飓风形成的预警准备时间相应增加，将给社会带来惠益。

This effort will address the genesis of tropical cyclones (and antecedent regions of low pressure and near-surface cyclonic wind patterns termed tropical depressions) through further study of the "marsupial paradigm." This conceptual model refers to a theory of hurricane formation in which the translation speed of one type of parent atmospheric disturbance (termed an "easterly wave") is matched the environmental flow so as to create a protective zone (or so-called "pouch") in which developing small-scale cyclonic circulation(s) are protected from hostile environmental conditions until further strengthening occurs. This study will be supported by data to be collected during the 2010 NSF-supported PREDICT (PRE-Depression Investigation of Cloud-systems in the Tropics) field campaign involving the NSF/NCAR GV research aircraft as well as complementary resources being provided by NASA and NOAA. This research will focus on conditions within the meso-alpha scale wave pouch region (having 200-2000 km horizontal extent), its interaction with the larger-scale environment, and impacts of this interaction on ultimate tropical cyclone formation. It will incorporate flight-level, dropsonde and radar data from the PREDICT field campaign, with reanalysis data, various satellite datasets, and the WRF-ARW numerical model to address three main questions: 1) Is a well-defined wave pouch a necessary condition for tropical cyclone development, and if so, how does it form? 2) Why do some waves exhibiting a deep pouch fail to develop into a tropical storm? 3) How does the Saharan Air Layer (SAL) affect tropical cyclogenesis, and why do some wave pouches provide protection from dry air intrusion while others do not? The intellectual merit of this effort centers on exploitation of the focused PREDICT dataset in conjunction with numerical model simulations conducted in the marsupial framework to lead to better understanding of tropical cyclogenesis. Broader impacts of this research include the education and training of two graduate students and the integration of tools and products into classroom learning activities, as well as support for an investigator drawn from an underrepresented group. Benefits to society will come through the increased understanding of tropical cyclogenesis and associated increases in warning lead time for hurricane formation.