Water Vapor, Clouds, and Aerosol in the Tropical Tropopause Layer with in situ and Profiling Measurements from Long Duration Strateole-2 Balloons

热带对流层顶层中的水蒸气、云和气溶胶，通过长期 Strateole-2 气球进行原位和剖面测量

• 批准号: 1643022
• 负责人: Terry Deshler
• 金额: $ 125.81万
• 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: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1643022&HistoricalAwards=false
• 关键词: Water; Vapor; Clouds; Aerosol; Tropical

The tropical tropopause layer (TTL) is 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). The TTL extends from about 14 to 18.5km over the tropics and is above the tops of all but the tallest convective clouds. It often contains thin cirrus clouds which, though difficult to see, play an outsized role in trapping outgoing radiation and thus warming the troposphere. It is sometimes called the "gateway to the stratosphere" because most of the water vapor in the stratosphere, and many other stratospheric constituents, enter the stratosphere by moving upward through the TTL. The stratosphere is extremely dry compared to the troposphere, but stratospheric water vapor is of interest because it has an important greenhouse effect and can lead to the formation of polar stratospheric clouds which play a role in ozone hole formation.This project seeks to improve understanding of TTL processes by building and launching several instruments on balloons intended to fly at the top of the TTL. The balloons are part of the Strateole-2 field campaign organized by the Centre National d'Etudes Spatiales (CNES), the French Space Agency, and the Laboratoire de Meteorologie Dynamic (LMD) of the University of Paris-Saclay. Strateole-2 is a five-year campaign, with a small validation deployment in 2018 and full science deployments in 2020-2021 and 2022-2023. Balloons are launched from the Seychelles (about 5S in the Indian Ocean), with the expectation that each balloon will circle the earth for up to 90 days and observe the TTL between 20S and 15N. This award supports US participation in the validation campaign and the first full science deployment, along with post-campaign analysis. It is one of three awards made to US PIs for participation in Strateole-2, the full set being AGS-1643022, AGS-1642277/1642246, and AGS-1642650/1653644.One instrument to be built and deployed is an optical particle detector referred to as the LASP Particle Counter (LPC, named after the Laboratory for Atmospheric and Space Physics at the University of Colorado). The LPC uses scattered laser light to detect aerosol particles with sizes ranging from 0.3 to 10 microns and is used to estimate the flux of aerosols entering the stratosphere through the top of the TTL. In addition to the LPC the PIs are developing an instrument package called RACHuTS, for Reel-down Aerosol Cloud Humidity and Temperature Sensor. The RACHuTS package weighs less than 2kg and is suspended from a nylon cable which is reeled down to 2km below the balloon gondola and then reeled back up again, each time generating a vertical profile of TTL conditions over 15 minutes. RACHuTS is lowered and raised 5 times each night while the balloon is aloft (the optical components do not function in daylight). The instruments integrated into RACHuTS are developed elsewhere. These include the Compact Optical Backscatter Aerosol Detector (COBALD, developed at ETH Zurich), the Fluorescence Advanced Stratospheric Hygrometer for Balloon (FLASH-B, developed at the Central Aerological Observatory in Moscow), and the Thermodynamic SENsor (TSEN, developed at LMD). A commercial radiosonde package is also used to record atmospheric pressure and GPS position.One issue to be addressed in the project is the extent to which supersaturation is an important consideration in determining how much water vapor passes through the TTL and enters the stratosphere. The amount of water vapor entering the stratosphere is limited by the temperature minimum at the tropopause, under the assumption that the amount of water vapor above that level cannot exceed the amount corresponding to 100% relative humidity at that level. But it is possibly for relative humidity to exceed 100% in cases where ice particle concentrations are low enough and ascent is fast enough to allow moisture to reach the stratosphere before sublimation can occur. The RACHuTS instruments are well suited to the study of supersaturation effects as temperature, humidity, and ice particle concentrations are observed together over a substantial portion of the depth of the TTL. A further issue, to be addressed using the LPC, is the transport of primary aerosols into the stratosphere. The PIs seek to constrain the size distribution of these areosols and address questions related to the stability of the distribution, its geographical variability, its relationship to convective overshooting, and previous observations of large particles with low number concentrations.The work has scientific broader impacts due to the value of the observations for addressing a variety of questions regarding TTL processes. RACHuTS and LPC observations will be made available to the research community from servers at LASP so that it can be freely examined by the research community. In addition, the project constitutes a demonstration of a novel technology for meteorological observations which 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.

热带对流层顶层（TTL）是对流层（云，降水和天气系统的领域）和平流层（其上包含臭氧层的寒冷干燥区域）之间的过渡区。 TTL在热带上空延伸约14至18.5公里，除了最高的对流云之外，它位于所有对流云的顶部。 它通常包含薄卷云，虽然很难看到，但在捕获向外辐射，从而使对流层变暖方面发挥了巨大作用。 它有时也被称为“通往平流层的大门”，因为平流层中的大部分水蒸气和许多其他平流层成分都是通过TTL向上移动进入平流层的。 与对流层相比，平流层极为干燥，但平流层水蒸气令人感兴趣，因为它具有重要的温室效应，并可导致形成极地平流层云，而平流层云在臭氧洞的形成中发挥作用，该项目旨在通过在打算在TTL顶部飞行的气球上建造和发射若干仪器来提高对TTL过程的认识。 这些气球是法国国家空间研究中心（CNES）、法国航天局和巴黎萨克雷大学气象动力学研究所（LMD）组织的“气球-2”实地活动的一部分。 “彗星-2”是一项为期五年的活动，2018年将进行小规模验证部署，2020-2021年和2022-2023年将进行全面科学部署。 气球从塞舌尔群岛（印度洋约5S）发射，预计每个气球将环绕地球长达90天，并观察20 S和15 N之间的TTL。该奖项支持美国参与验证活动和第一次全面的科学部署，沿着活动后分析。 它是美国PI参与的三个奖项之一，全套是AGS-1643022，AGS-1642277/1642246和AGS-1642650/1653644。将建造和部署的一种仪器是称为LASP粒子计数器的光学粒子探测器（LPC，以科罗拉多大学大气和空间物理实验室命名）。LPC使用散射激光探测尺寸在0.3至10微米之间的气溶胶颗粒，并用于估计通过TTL顶部进入平流层的气溶胶通量。 除了LPC，PI正在开发一种名为RACHuTS的仪器包，用于卷轴式气溶胶云湿度和温度传感器。 RACHuTS包重量不到2公斤，悬挂在尼龙电缆上，该电缆被卷到气球吊舱下方2公里处，然后再次卷起来，每次产生超过15分钟的TTL条件的垂直剖面。RACHuTS每晚在气球升空时下降和上升5次（光学组件在白天不起作用）。纳入区域协调住房和城市发展支助系统的工具在其他地方开发。 其中包括苏黎世联邦理工学院研制的小型光学后向散射气溶胶探测器（COBALD）、莫斯科中央高空气象观测站研制的高级气球用荧光平流层湿度计（FLASH-B）和LMD研制的热力学传感器（TSEN）。商业无线电探空仪包还用于记录大气压力和GPS位置。该项目需要解决的一个问题是，过饱和度在多大程度上是确定有多少水蒸气通过TTL并进入平流层的重要考虑因素。 进入平流层的水汽量受到对流层顶最低温度的限制，假设该水平以上的水汽量不能超过该水平100%相对湿度的对应量。 但是，在冰粒浓度足够低且上升足够快的情况下，相对湿度可能超过100%，从而使水分在升华发生之前到达平流层。 RACHuTS仪器非常适合研究过饱和效应，因为温度、湿度和冰粒浓度在TTL深度的相当大的一部分上一起观测。 使用LPC处理的另一个问题是初级气溶胶向平流层的传输。 PI试图限制这些气溶胶的大小分布和解决有关的问题的稳定性的分布，其地理变异性，其关系到对流过冲，和以前的观测大颗粒低数concentration.The工作有科学更广泛的影响，由于价值的意见，解决各种有关TTL过程的问题。 RACHuTS和LPC观测结果将从LASP的服务器提供给研究界，以便研究界可以免费检查。 此外，该项目还展示了一种新的气象观测技术，这种技术可能具有广泛的科学应用。 除了这些考虑因素，该项目还支持博士后研究助理，从而发展该研究领域未来的科学劳动力。

项目成果

First Super‐Pressure Balloon‐Borne Fine‐Vertical‐Scale Profiles in the Upper TTL: Impacts of Atmospheric Waves on Cirrus Clouds and the QBO

第一个超压气球 - TTL 上部的精细 - 垂直 - 尺度剖面：大气波对卷云和 QBO 的影响

• DOI: 10.1029/2021gl097596
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Bramberger, Martina;Alexander, M. Joan;Davis, Sean;Podglajen, Aurelien;Hertzog, Albert;Kalnajs, Lars;Deshler, Terry;Goetz, J. Douglas;Khaykin, Sergey
• 通讯作者: Khaykin, Sergey

A reel-down instrument system for profile measurements of water vapor, temperature, clouds, and aerosol beneath constant-altitude scientific balloons

用于恒定高度科学气球下方水蒸气、温度、云和气溶胶轮廓测量的卷轴仪器系统

• DOI: 10.5194/amt-14-2635-2021
• 发表时间: 2021
• 期刊: Atmospheric Measurement Techniques
• 影响因子: 3.8
• 作者: Kalnajs, Lars E.;Davis, Sean M.;Goetz, J. Douglas;Deshler, Terry;Khaykin, Sergey;St. Clair, Alex;Hertzog, Albert;Bordereau, Jerome;Lykov, Alexey
• 通讯作者: Lykov, Alexey