Interactions between Tropospheric Water Vapor and Potential Vorticity in Tropical Disturbances

了解推动热带纬度(南纬30度-北纬30度)大气运动的物理过程已被证明是大气科学的重大挑战之一。这一挑战的部分原因是云和降水过程在热带环流中发挥的中心作用。虽然关于驱动热带降雨的过程还有很多需要了解的地方，但近几十年来已经取得了许多进展。例如，研究发现，大气中水蒸气的浓度在热带降雨的调节中起着核心作用。尽管取得了这一突破，但我们对热带地区水蒸气、降水和大尺度大气运动如何发生的了解仍然有限。这项研究试图了解这种相互作用对大气流动中的扰动，即所谓的热带扰动。这些扰动包括水平流动主要是旋转的扰动，如东风波、赤道Rossby波和季风低气压系统。这些系统在加勒比海等热带多个区域的水文循环中起着重要作用，经常发展为热带气旋，对温带地区影响深远。这项研究将对热带降水的组织提供重要的见解，从而改善这些过程在模式中的表现。此外，由于这些扰动有时会发展成热带气旋，这项研究提供的见解可能对热带气旋发生的预测感兴趣。该项目的结果有很大的潜力形成一个新的热带运动的一般理论框架，可能会被纳入热带气象学的一门课程。一名研究生和一名博士后将通过该奖项获得资助。从研究项目中获得的知识也将用于公共宣传和通识教育。新的统计技术将用于分析水汽、降水和环流之间的相互作用。该研究小组将检查观测数据和数值模型的模拟，以获得清晰、清晰的图像，了解这些“旋转热带扰动”中的环流如何调节水蒸气的分布和降水过程。这项研究将阐明水蒸气改变降水的方式，以及降雨的这种变化如何影响这些扰动的循环。这个奖项反映了NSF的法定使命，通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为是值得支持的。

Understanding the physical processes that drive atmospheric motions in the tropical latitudes (30 degrees South-30 degrees North) has proven to be one of the great challenges of atmospheric sciences. This challenge arises in part due to the central role that clouds and precipitation processes play in the tropical circulation. While there is much that remains to be learned about the processes that drive tropical rainfall, numerous advancements have been made in recent decades. For example, research has found that the concentration of water vapor in the atmosphere plays a central role in the regulation of tropical rainfall. In spite of this breakthrough, our understanding of how water vapor, precipitation and large-scale atmospheric motions in the tropics occur remains limited. This study seeks to understand such interactions on perturbations in the atmospheric flow that are known as tropical disturbances. These include disturbances whose horizontal flow is largely rotational such as easterly waves, equatorial Rossby waves and monsoon low-pressure systems. These systems play an important role in the hydrologic cycle of multiple regions in the tropics, such as the Caribbean, and often develop into tropical cyclones, and have far-reaching impacts in the extratropics. The research will provide important insights on the organization of precipitation in the tropics, which will lead to improvements in the representation of these processes in models. Furthermore, because these disturbances sometimes develop into tropical cyclones, insights provided by this study may be of interest to the forecasting of tropical cyclogenesis. Results from the project have great potential to form a new general theoretical framework for tropical motions, which may be included in a course in tropical meteorology. A graduate student and a postdoc will be supported through this award. The knowledge gained from the research project will also be used for public outreach and general education. Novel statistical techniques will be used to analyze the interactions among water vapor, precipitation and circulation. The team will examine observational data and simulations from numerical models to obtain a lucid, clear picture of how circulations in these "rotational tropical disturbances" modulate the distribution of water vapor and precipitation processes. The study will elucidate the ways in which water vapor modifies precipitation, and how this change in rainfall affects circulations of these disturbances. The role that thermodynamic processes such as radiation and condensation play in this interplay will also be examined.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.