US-France Workshop to Establish an International Collaboration for the Strateole-2 Campaign on Science of the Equatorial Upper Troposphere / Lower Stratosphere

本项目将资助一个由美国多所大学和研究机构的科学家组成的小组，在法国参加一个为期三天的研讨会，以建立一个新的热带对流层上层/平流层下层科学国际合作项目。从stratole 2中获得的对流层和平流层之间的动力学、化学和动量交换的新认识对于新一代的气候模式至关重要，这些模式扩展到1hpa的高度，并试图将平流层的变率纳入我们对气候变化的理解。研讨会还将为来自波多黎各的一群对气球平台感兴趣的物理学和工程学本科生提供一个机会，让他们了解平流层研究的主要动机，并从新的角度看待进行这类测量的工程挑战。平流层的水蒸气在平流层的辐射收支和调节地表变暖方面起着重要的作用。热带对流层顶层（TTL）通常被认为是通往全球平流层的门户，然而，关于化学输送途径以及潮湿空气如何向上输送并最终在TTL中脱水的问题仍然存在争议。研究的目的是：1)确定热带波和深层对流对水汽进入平流层和热带对流层顶层卷云形成的作用；2)通过小尺度重力波了解行星尺度波在准两年一次振荡强迫中的相对作用；3)表征本底气溶胶载荷、气溶胶大小分布，并分析其变化规律。而热带平流层下层的臭氧化学反应限制了这种运输。新型超压气球仪器，包括光纤温度分析器、新型pico-SDLA二极管激光测量水蒸气和轻型霜点湿度计，将以前所未有的精度测量现场冷点温度和水蒸气，将是该领域新进展的关键。

a non-technical explanation This project will support a team of scientists from several US universities and research institutes to participate in a 3-day workshop in France to establish a new international research collaboration for science of the Tropical Upper Troposphere / Lower Stratosphere (UT/LS).The new understanding of the dynamics, chemistry, and momentum exchange between the troposphere and stratosphere gained from Strateole 2 is critical for the new generation of climate models that extend as high as 1 hPa and attempt to incorporate variability in the stratosphere into our understanding of climate change. The workshop will also provide an opportunity for a group of undergraduate physics and engineering students from Puerto Rico interested in balloon platforms to learn about key motivations for stratospheric research, and get a new perspective on engineering challenges for making these types of measurements.a technical description Stratospheric water vapor plays an important role in the radiative budget of the stratosphere as well as in modulating surface warming. The tropical tropopause layer (TTL) is often referred to as the gateway to the global stratosphere, however there are still debates on the chemical transport pathways and how moist air is transported upward and eventually dehydrated in the TTL. The objectives of the research are to 1) determine the roles of tropical waves and deep convection on the transport of water vapor into the stratosphere and formation of cirrus clouds in the tropical tropopause layer, 2) understand the relative roles of planetary-scale waves through small scale gravity waves in the forcing of the quasi-biennial oscillation, 3) characterize background aerosol loading, aerosol size distributions, and ozone chemistry in the tropical lower stratosphere to constrain this transport. New superpressure balloon instrumentation, including a fiber-optic temperature profiler, new pico-SDLA diode laser measurements of water vapor and lightweight frost point hygrometers that measure in-situ cold point temperatures and water vapor with unprecedented accuracy, will be key to new advances in this field.