Continuing Measurements of Water Vapor, Clouds, Aerosol, and Waves Above, and Across, the Tropical Tropopause Layer with in Situ Instruments on Circum-Tropical Isopycnic Balloons

使用环热带等密度气球上的现场仪器持续测量热带对流层顶层上方和上方的水蒸气、云、气溶胶和波浪

• 批准号: 2336110
• 负责人: Terry Deshler
• 金额: $ 120.18万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-15 至 2027-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2336110&HistoricalAwards=false
• 关键词: Continuing; Measurements; Water; Vapor; Clouds

This award supports the continued participation of the Principal Investigators (PIs) in the Strateole-2 field campaign, organized by the French space agency (CNES, for Centre National d'Etudes Spatiales) and the Laboratory for Dynamic Meteorology (LMD) at the University of Paris-Saclay. The campaign makes observations of the tropical tropopause layer (TTL), the layer of the atmosphere from roughly 14km to 18km between the tropical troposphere and stratosphere, using balloons designed to float at a constant altitude for flights of up to 3 months. The balloons are launched from the Seychelles and float around the equator at the top of the TTL (near 18km) or in the lower stratosphere at an altitude close to 20km. Strateole-2 was planned as a set of three deployments, a preliminary engineering deployment with 8 balloon flights followed by two science deployments with 20 flights each. The first two deployments took place in 2019 and 2021 and funds for the PIs' participation in these deployments were provided through AGS-1643022. Funds provided here support participation in the third campaign, scheduled to begin in October 2025.The primary task under this award is the production of balloon-borne instruments to observe temperature, moisture, aerosols, and cirrus cloud ice particles. One instrument is the LASP Particle Counter (LPC), named for the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder. The LPC flies on the balloon gondola and detects aerosols and ice particles using laser backscatter. It can determine the concentration of particles of sizes ranging from 0.3 to 30 microns in 32 size bins. The LPC is accompanied by a moisture and temperature sensor developed for use in weather balloons, the Vaisala RS41, which can detect moisture at the low humidities found in the TTL and lower stratosphere. Five LPCs will be flown in the 2025 deployment, three at 18km and two at 20km.A second instrument is the Reeldown Aerosol, Cloud, Humidity and Temperature Sensor (RACHuTS), a 2kg package which is reeled up and down on a cord to generate soundings extending 2km below the balloon. RACHuTS integrates the Thermodynamic SENsor (TSEN, developed by a French team) with a smaller version of the LPC called the ROPC (RACHuTS Optical Particle Counter, with 8 size bins from 0.3 to 10 microns), along with an RS41 and the Tunable Diode Laser (TDL) moisture sensor developed under AGS-2233136. TDL is an improvement over the FLASH-B moisture sensor used in the previous deployments since it is not sensitive to ambient light and can thus be used during the day, doubling the opportunities for profiling. RACHuTS makes profiles with one meter vertical resolution, with one profile as it descends and another as it returns to the gondola. Three RACHuTS profilers will be flown in the 2025 deployment, all at 18km.As in the earlier deployments the measurements taken using LPC and RACHuTS will be used to address three issues in TTL science. The first is the extent to which supersaturation is an important factor in determining humidity in the stratosphere. Stratospheric humidity is thought to be limited by the saturation vapor pressure at the coldest temperature air encounters as it rises through the TTL to enter the stratosphere, under the assumption that water vapor condensation or deposition occurs when relative humidity reaches 100%. But data from previous deployments shows relative humidities above 150%, suggesting that the cold point saturation vapor pressure may not be as strict a limit as previously supposed. A related issue is the role of atmospheric waves in the formation of cirrus clouds in the TTL, as previous RACHuTS deployments and other evidence suggests that the majority of ice particle layers within the TTL are generated by cooling associated with rising motions in waves. The layers can be quite thin, perhaps only 10 meters, thus the one meter resolution of RACHuTS profiles is necessary to observe the layers. The third issue to be addressed in the project is the finding of layers of large particles, in the size range from 2 to 20 microns, at relative humidities too low to allow ice formation. The nature of these particles has yet to be determined. One strategy for studying them is to fly the LPC on two balloons at the 20km level, which is above the TTL and typically too warm and dry to support ice clouds. The detection of super-micron particles at that level would be a strong argument that the particles are not composed of ordinary ice.The work has scientific broader impacts due to the unique dataset to be collected, in particular the long sampling time, high vertical resolution, and high quality of the observations. RACHuTS and LPC observations will be made freely available to the research community so that they can be used in ways not anticipated here. In addition, the project develops novel technologies for meteorological observations that could have a wide array of scientific applications. Beyond these considerations, the project supports a postdoctoral research associate, thereby developing the future scientific workforce in this research area. The project develops a substantial international collaboration and also provides support and training to a research scientist and an undergraduate student at the University of Colorado.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.

该奖项支持由法国航天局（CNES，中心国家D'Etudes Spatiales）和帕里斯 - 帕里斯 - 萨克莱大学（University of Paris-Saclay）组织的首席研究人员（PIS）在法国航天局（CNES，CNES National d'Etudes Spatiales）和动态气象学（LMD）实验室组织的Strateo-2现场运动。该运动使观察热带对流层层层（TTL），这是在热带对流层和平流层之间的大气层从大约14公里到18公里的大气层，使用了气球，该气球设计用于在恒定的高度上漂浮，可在恒定的高度上飞行3个月。 气球是从塞舌尔发射的，并在TTL顶部（接近18公里）或在接近20公里的海拔高度下漂浮在赤道周围。 Startole-2计划是一组三个部署，这是一个初步的工程部署，其中8个气球飞行，然后是两次科学部署，每次飞行20次飞行。前两个部署于2019年和2021年进行，PIS参与这些部署的资金由AGS-1643022提供。 此处提供的资金支持参与第三次活动，计划于2025年10月开始。该奖项下的主要任务是生产气球传播仪器，以观察温度，水分，气溶胶和卷心云冰颗粒。 一种仪器是LASP粒子计数器（LPC），该仪器以科罗拉多大学博尔德大学大气和太空物理实验室命名。 LPC使用激光反向散射在气球缆车上飞行，并检测气溶胶和冰颗粒。它可以确定尺寸的颗粒浓度范围从32块中的0.3至30微米。 LPC伴随着用于天气气球的水分和温度传感器，即Vaisala RS41，可以在TTL和下层平流层中发现的低湿度下检测水分。 在2025年部署中将飞行五个LPC，在18公里处进行三个LPC，第二个仪表是第二个LPC，第二个乐器是Reeldown气溶胶，云，湿度和温度传感器（Rachuts）（Rachuts），这是一个2kg的包装，这是一个2kg的包装，它在绳索上上下旋转，以产生伸展2 km下方2km的声音。 Rachuts与较小版本的LPC集成了热力学传感器（TSEN，TSEN，由RACHUTS光学粒子计数器，8尺寸的垃圾箱，从0.3到10微米），以及RS41和可调二极管激光（TDL）的水分传感器（TDL）在AGS-223333333333336下开发的lpc。 TDL是对先前部署中使用的闪存B水分传感器的改进，因为它对环境光不敏感，因此可以在白天使用，使分析的机会增加了一倍。 Rachuts以一个米的垂直分辨率制作了轮廓，其中一个轮廓下降时，另一个轮廓返回到吊船时。 在2025年的部署中将驾驶三名Rachuts剖道师，而在早期部署中，所有使用LPC和Rachuts进行的测量将用于解决TTL科学中的三个问题。 首先是过饱和是确定平流层湿度的重要因素。 在最冷的温度空气遇到的饱和蒸气压在TTL上以进入平流层的饱和蒸气压的限制，这是在假设水蒸气凝结或沉积相对湿度达到100％时发生的。 但是先前部署的数据表明，相对湿度高于150％，这表明冷点饱和蒸气压力可能不如先前想象的那样严格。 一个相关的问题是大气波在TTL中形成卷云中的作用，因为先前的Rachuts部署和其他证据表明，TTL内的大多数冰层层是通过与波浪中的上升运动相关的冷却而产生的。 这些层可能很薄，也许只有10米，因此需要一米的rachuts轮廓分辨率才能观察这些层。 项目中要解决的第三个问题是发现大颗粒的层，尺寸在2至20微米之间，相对湿度太低而无法形成冰。这些颗粒的性质尚未确定。 研究它们的一种策略是将LPC在20公里水平上的两个气球上飞行，该气球高于TTL，通常太热又干燥，无法支撑冰云。 在该级别上检测超级微调颗粒将是一个有力的论点，即这些颗粒不是由普通冰组成的。由于要收集的独特数据集，尤其是长时间的采样时间，高垂直分辨率和高质量的观察结果，这项工作具有更广泛的影响。 Rachuts和LPC观察结果将免费提供给研究社区，以便可以在这里以无法预料的方式使用它们。此外，该项目为气象学观察开发了新的技术，这些技术可能具有广泛的科学应用。除了这些考虑之外，该项目还支持博士后研究助理，从而在该研究领域发展了未来的科学劳动力。 该项目开发了一项实质性的国际合作，还为科罗拉多大学的研究科学家和本科生提供支持和培训。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估来评估值得支持的。