Strateole-2: Atmospheric Wave Influences on Cirrus, Water Vapor, and Global Circulation Near the Tropical Tropopause

Strateole-2：大气波对热带对流层顶附近的卷云、水蒸气和全球环流的影响

• 批准号: 2231667
• 负责人: Martina Bramberger
• 金额: $ 76.89万
• 依托单位: NorthWest Research Associates, Incorporated
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2231667&HistoricalAwards=false
• 关键词: Strateole; Atmospheric; Wave; Influences; Cirrus

This award supports analysis of observations collected in the first two deployments of the Strateole-2 field campaign, which took place in the winters of 2019/2020 (8 flights) and 2021/2022 (17 flights). Strateole-2 is a long-duration ballooning campaign organized by the Centre National d'Etudes Spatiales (CNES), the French national space agency. The balloons were launched from the Seychelles and drifted around the equator for up to two months following the winds of the lower stratosphere. The campaign used a variety of instruments to observe the tropical tropopause layer (TTL), the transition zone between the troposphere (the domain of clouds, precipitation, and weather systems) and the stratosphere (the cold and dry region above it which contains the ozone layer). A primary focus of Strateole-2 is gravity waves, meaning wave motions in the atmosphere for which the primary restoring force is gravity. Such waves are generated by vertical motions occurring in the deep convective clouds over tropical oceans but they can have horizontal wavelengths much larger than convective systems, with sufficient extent in latitude to be affected by the Coriolis force and its variation with latitude. These waves are of interest because they provide the vertical transport of horizontal momentum which drives the quasi-biennial oscillation (QBO), a reversal of the winds in the equatorial stratosphere that starts at high levels and descends over the next two years. The up-and-down motions in the waves also affect the temperature of the TTL, and the colder temperatures occurring in the upward displacements promote the condensation of ambient water vapor, promoting the formation of thin cirrus clouds which block outgoing infrared radiation and thus have an effect on Earth's energy balance. The formation of ice particles in cirrus clouds also reduces the amount of water vapor entering the stratosphere, where it has additional effects on the planetary energy balance.Work performed here focuses specifically on waves which are long, with horizontal wavelengths of perhaps 1,000km, but shallow, with vertical wavelengths less than a kilometer, and periods of a few days. The project takes advantage of the NSF-funded suite of instruments flown in the deployments, including the radio occultation receiver (ROC) supported under AGS-1642650, the fiber optic temperature profiler (FLOATS) developed under AGS-1642277, and the reel-down instrument package (RACHuTS) developed under AGS-1643022. It also uses data from instruments developed by researchers in France, including a balloon-borne lidar (BeCOOL) and an infrared water vapor sensor (PicoSTRAT), as well as onboard thermometers, barometers, and GPS receivers. These data sources are used in combination with satellite data and reanalysis products, and specialized simulations with enhanced vertical resolution are performed by unfunded collaborators at the European Centre for Medium-Range Weather Forecasts. One issue to be addressed is the generation of these pancake-like waves, which must somehow be generated by localized convection despite their long horizontal wavelengths. Work on momentum transport considers wave breaking and subsequent generation of turbulence as well as the calculation of wave momentum flux.The work has broader impacts through its potential for improving the representation of the QBO in models used for long-range weather prediction. Models have difficulty representing the QBO, in part due to the difficulty of representing the effect of gravity wave momentum transport, and the QBO plays important roles in modulating the potentially predictable forms of subseasonal weather variations. In addition, the radiative effects of cirrus clouds and stratospheric water vapor are among the factors that matter for understanding and anticipating anthropogenic climate change. In addition, the PIs conduct public outreach and education by participating in an effort to correct scientific misunderstanding in social media, working with colleagues to develop easy-to-use tutorials that give users access to scientific data and information. The project provides support and training to a postdoctoral fellow, thereby promoting the scientific workforce in this research area.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.

该奖项支持对Strateo-2现场运动的前两个部署中收集的观察结果的分析，该活动发生在2019/2020的冬季（8次飞行）和2021/2022（17个航班）。 Strateo-2是一项由法国国家航天局（CNES）中心国家空间（CNES）组织的长期气球运动。 气球是从塞舌尔发射的，在较低平流层的风中绕着赤道漂流了长达两个月。 该运动使用各种仪器来观察热带对流层滨层（TTL），对流层（云，降水和天气系统的域）和平流层（其中包含臭氧层的冷和干燥区域）之间的过渡区。 Strateo-2的主要重点是重力波，这意味着主要恢复力为重力的大气中的波动运动。这样的波是由热带海洋上深的对流云中发生的垂直运动产生的，但它们的水平波长可能比对流系统大得多，其纬度足够的纬度可以受到科里奥利力及其与纬度变化的影响。 这些波是引人注目的，因为它们提供了水平动量的垂直运输，该水平动量驱动了准生物振荡（QBO），这是赤道平流层中风的逆转，该风速从高水平开始，并在未来两年内下降。波浪中的上下动作也会影响TTL的温度，并且在向上的位移中发生的较冷温度促进了环境水蒸气的冷凝，从而促进了薄卷云云的形成，从而阻止了向外爆发的红外辐射，从而对地球能量平衡产生影响。 卷云中的冰颗粒的形成也减少了进入平流层的水蒸气的量，它对行星能量平衡具有其他影响。在这里进行的工作专门集中在长的波浪上，水平波长的水平波长约为1,000km，但垂直波长少于垂直波长，而不是远小于一定的千禧时间和几天。 该项目利用了部署中飞行的NSF资助的仪器套件，包括根据AGS-1642650支持的无线电隐匿性接收器（ROC），根据AGS-1642277为AGS-1642277开发的光纤温度探测器（FLOATS），以及在AGS-1642277中开发的卷轴仪表（RACHUTS）（RACHUTS）（RACHUTS）。 它还使用来自法国研究人员开发的仪器的数据，包括气球传播的激光雷（Becool）和红外水蒸气传感器（Picostrat），以及机上温度计，气压计和GPS接收器。这些数据源与卫星数据和重新分析产品结合使用，并且具有增强垂直分辨率的专门模拟是由欧洲中型天气预报中心的无资金合作者进行的。要解决的一个问题是这些类似薄煎饼的波的产生，尽管水平波长很长，但必须以某种方式通过局部对流产生。 动量传输的工作考虑了波浪的破裂和随后的湍流以及波动动量通量的计算。这项工作通过改善用于长期天气预测的模型中的QBO代表而产生了更大的影响。 模型很难代表QBO，部分原因是代表重力波动量运输的效果的困难，QBO在调节潜在可预测的次生天气变化的形式中起着重要作用。 此外，卷云和平流层水蒸气的辐射作用是理解和预期人为气候变化的因素。 此外，PIS通过参与纠正社交媒体中的科学误解，与同事合作开发易于使用的教​​程，使用户可以访问科学数据和信息，从而进行公众推广和教育。 该项目为博士后研究员提供了支持和培训，从而促进了该研究领域的科学劳动力。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，认为值得通过评估来获得支持。