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: 2335082
• 负责人: Martina Bramberger
• 金额: $ 44.44万
• 依托单位: NorthWest Research Associates, Incorporated
• 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=2335082&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.

该奖项支持主要调查员继续参与法国航天局（法国国家空间研究中心）和巴黎-萨克雷大学动态气象学实验室组织的“卫星-2”实地活动。该活动使用设计为在恒定高度漂浮长达3个月的气球，对热带对流层和平流层之间约14公里至18公里的大气层热带对流层顶层进行观测。 这些气球从塞舌尔群岛发射，漂浮在TTL顶部上方的赤道周围，或者在平流层下部，高度接近20公里。 Strategole-2计划分为三次部署，首先是初步工程部署，其中包括8次气球飞行，然后是两次科学部署，每次20次飞行。前两次部署分别于2019年和2021年进行，PI参与这些部署的资金通过AGS-1642277提供。 第三次部署计划于2025年10月开始。这里提供的资金支持开发和部署一种缩写为RATS的新仪器，即卷轴式大气温度传感器。 粗略地说，大鼠是一个温度计下降的一个长绳下面的气球吊舱，其中包含第二个温度计。两个温度计之间的温差可以用来探测重力波，类似于海洋表面波的大气波，只是它们可以垂直和水平传播。大鼠可以探测到重力波，因为波的上下运动会引起冷却和变暖，因此两个适当分离的温度计之间的温差可以记录波的通过。该提案的标题是使用RATS温度计对平流层下部的大气热带波进行定性，其动机来自重力波在驱动准两年振荡（QBO）中的作用，准两年振荡是指赤道上空纬向风向的逆转，始于平流层上部，在略长于两年的时间内下降到对流层顶。 QBO对亚季节天气预测很重要，因为它与影响世界各地天气的气候变化模式有关。 用于天气预测的模型很难捕捉到QBO，部分原因是驱动它的波的波长小于典型的模型网格间距，特别是在垂直方向。 RATS可以探测到两个温度计之间距离的2到30倍之间的垂直波长的波，温度计设置为200米或300米，以捕获400米到6公里或600米到9公里的波长。 较长的波长可以通过运行模型来分辨，从而与模型输出进行比较，而较短的波长则无法分辨。该合同涵盖了RATS硬件的开发，其中包括一个较低的测量单元（LMU），该单元包含一个温度计（由法国国家空间研究中心开发），沿着一个RS 41无线电探空仪传感器模块（来自维萨拉），用于测量温度、湿度和压力，以及一个用于确定位置的GPS接收器。 LMU使用线轴和滑轮系统升高和降低，使其能够停靠在吊舱上进行发射，并在气球达到飞行高度时下降。 吊舱内装有沿着的温度计、气压计和全球定位系统接收器。这项工作具有社会意义，因为通过改进QBO波驱动的表现，可以更好地进行长期天气预报。该项目涉及与两个业务天气预报中心的合作，从而提供了从研究到业务的连接。 所有的现场活动数据都提供给全球研究界，以追求TTL物理和动力学的额外研究课题。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。