Collaborative Research: Characterizing Atmospheric Tropical-waves of the Lower Stratosphere with Reel-down Atmospheric Temperature Sensing for Strateole-2--RATS Chasing CATS!

合作研究：利用 Strateole-2 的卷轴大气温度传感来表征平流层下部的大气热带波——RATS 追逐 CATS！

• 批准号: 2335083
• 负责人: Lars Kalnajs
• 金额: $ 65.5万
• 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: 2024-03-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2335083&HistoricalAwards=false
• 关键词: Collaborative; Research; Characterizing; Atmospheric; Tropical

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 just above the top of the TTL or in the lower stratosphere at an altitude near 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-1642277. The third deployment is scheduled to begin in October 2025.Funds provided here support the development and deployment of a new instrument with the acronym RATS, for Reel-down Atmospheric Temperature Sensor. Roughly speaking RATS is a thermometer lowered on a long tether below a balloon gondola which contains a second thermometer. The difference in temperature between the two thermometers can be used to detect gravity waves, atmospheric waves similar to ocean surface waves only they can propagate vertically as well as horizontally. RATS can detect gravity waves because the up and down motions of the waves cause cooling and warming, thus the difference in temperature between two appropriately separated thermometers can record the passage of a wave. The title of the proposal refers to the use of the RATS thermometers for the Characterization of Atmospheric Tropical waves of the lower Stratosphere (CATS).Motivation for the work comes from the role of gravity waves in driving the Quasi-Biennial Oscillation (QBO), the reversal in zonal wind direction over the equator that begins in the upper stratosphere and descends to the tropopause over a period slightly longer than two years. The QBO matters for subseasonal weather prediction because it has been linked to modes of climate variability that influence weather around the world. Models used for weather prediction have difficulty capturing the QBO, in part because the waves that drive it have wavelengths that are smaller than typical model grid spacings, particularly in the vertical. RATS can detect waves with vertical wavelengths between 2 and 30 times the distance between the two thermometers, which is set to either 200m or 300m to capture wavelengths from 400m to 6km or 600m to 9km. The longer wavelengths can be resolved by operational models and thus compared with the model output while the shorter ones are unresolved.The award covers the development of the RATS hardware, which includes a Lower Measuring Unit (LMU) containing a thermometer (developed by CNES) along with an RS41 radiosonde sensor module (from Vaisala) to measures temperature, humidity, and pressure, and a GPS receiver for determining position. The LMU is raised and lowered using a spool and pulley system that allows it to be docked to the gondola for launch and reeled down when the balloon reaches its flight altitude. The gondola contains a second thermometer along with a barometer and GPS receiver.The work is of societal interest given the prospects for better long-range weather predictions through improved representation of the wave driving of the QBO. The Strateole-2 field campaign involves collaborations with two operational weather prediction centers, thereby providing a connection from research to operations. All field campaign data is made available to the global research community to pursue additional research topics on TTL physics and dynamics.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.

该奖项支持首席研究员 (PI) 继续参与由法国航天局（CNES，国家空间研究中心）和大学动态气象学实验室 (LMD) 组织的 Strateole-2 实地活动巴黎-萨克雷。该活动使用设计为在恒定高度漂浮的气球进行长达 3 个月的飞行，对热带对流层顶层 (TTL) 进行观测，该层是热带对流层和平流层之间约 14 公里至 18 公里的大气层。 气球从塞舌尔发射，围绕赤道漂浮在 TTL 顶部上方或海拔近 20 公里的低平流层中。 Strateole-2 计划分为三项部署，一项是初步工程部署，进行 8 次气球飞行，随后是两项科学部署，每次 20 次飞行。前两次部署于 2019 年和 2021 年进行，通过 AGS-1642277 为 PI 参与这些部署提供资金。 第三次部署计划于 2025 年 10 月开始。此处提供的资金用于支持新仪器的开发和部署，该仪器的缩写为 RATS（Reel-down 大气温度传感器）。 粗略地说，RATS 是一个温度计，用一条长绳系在气球吊舱下方，气球吊舱内还装有第二个温度计。两个温度计之间的温度差可用于检测重力波、大气波，类似于海洋表面波，只是它们可以垂直和水平传播。 RATS可以探测到重力波，因为重力波的上下运动会导致冷却和变暖，因此两个适当分开的温度计之间的温差可以记录重力波的经过。该提案的标题是指使用 RATS 温度计来表征平流层下部的大气热带波 (CATS)。这项工作的动机来自重力波在驱动准两年期振荡 (QBO) 中的作用，赤道上空纬向风向的逆转，从平流层上部开始，在略长于两年的时间内下降到对流层顶。 QBO 对于次季节天气预报很重要，因为它与影响世界各地天气的气候变化模式有关。 用于天气预报的模型很难捕获 QBO，部分原因是驱动 QBO 的波的波长小于典型模型网格间距，特别是在垂直方向上。 RATS 可以检测垂直波长为两个温度计之间距离的 2 至 30 倍的波，该距离设置为 200m 或 300m，以捕获 400m 至 6km 或 600m 至 9km 的波长。 较长的波长可以通过操作模型来解析，从而与模型输出进行比较，而较短的波长则无法解析。该奖项涵盖了 RATS 硬件的开发，其中包括包含温度计的下测量单元 (LMU)（由 CNES 开发）以及用于测量温度、湿度和压力的 RS41 无线电探空仪传感器模块（来自维萨拉）以及用于确定位置的 GPS 接收器。 LMU 使用线轴和滑轮系统进行升高和降低，使其能够停靠在吊舱上进行发射，并在气球到达其飞行高度时卷起。 吊舱包含第二个温度计、气压计和 GPS 接收器。这项工作具有社会意义，因为通过改进 QBO 波浪驱动的表示，有望实现更好的远程天气预报。 Strateole-2 实地活动涉及与两个运营天气预报中心的合作，从而提供从研究到运营的联系。 所有现场活动数据均提供给全球研究界，以寻求有关 TTL 物理和动力学的其他研究课题。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。