RAPID: In-situ Observations to Characterize Multi-Scale Turbulent Atmospheric Processes Impacting Climate at Southern High Latitudes

RAPID：通过现场观测来表征影响南部高纬度地区气候的多尺度湍流大气过程

• 批准号: 2326960
• 负责人: Abhiram Doddi
• 金额: $ 19.97万
• 依托单位: University of Colorado at Boulder
• 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: 2023-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2326960&HistoricalAwards=false
• 关键词: RAPID; situ; Observations; Characterize; Multi

This international collaboration between the University of Colorado, the University of Kyoto, and the National Institute of Polar Research in Tokyo, will investigate the sources of atmospheric turbulence in coastal Antarctica. Strong winds forced against terrain produce waves called atmospheric gravity waves, which can grow in amplitude as they propagate to higher altitudes, becoming unstable, breaking, and causing turbulence. Another source of turbulence is shear layers in the atmosphere, where one layer of air slides over another, resulting in Kelvin-Helmholtz Instabilities. Collectively, both play important roles in accurately representing the Antarctic climate in weather prediction models. Collecting new turbulence observations in these remote southern high latitudes will improve wind and temperature forecasts of the Antarctic climate. This project will observe gravity wave and shear-induced turbulence dynamics by deploying custom high-altitude balloon systems in coordination and collaboration with a powerful remote sensing radar and multiple long-duration balloons during an observational field campaign at the Japanese Antarctic Syowa station.This research is motivated by the fact that the sources representing realistic multi-scale gravity wave (GW) drag, and Kelvin-Helmholtz Instability (KHI) dynamics, along with their contributions to momentum and energy budgets due to turbulent transport/mixing, are largely missing in the current General Circulation Model (GCM) parameterization schemes, resulting in degraded synoptic-scale forecasts at southern high latitudes. This project utilizes high-resolution in-situ turbulence instruments to characterize the large-scale dynamics of 1) orographic GWs produced by katabatic forcing, 2) non-orographic GWs produced by low-pressure synoptic-scale events, and 3) KHI instabilities emerging in a wide range of scales and background environments in the coastal Antarctic region. The project will deploy dozens of low-cost balloon systems equipped with custom in-situ turbulence and radiosonde instruments at the Japanese Syowa station in Eastern Antarctica. Balloon payloads descend slowly from an apogee of 20 km to provide high- resolution, wake-free turbulence observations, with deployment guidance from the PANSY radar at Syowa, in coordination with the LODEWAVE long duration balloon experiment. The combination of in-situ and remote sensing turbulence observations will quantify the structure and dynamics of small-scale turbulent atmospheric processes associated with GWs and KHI, thought to be ubiquitous in polar environments but rarely observed. Momentum fluxes and turbulence dissipation rates measured over a wide range of scales and background environments will provide datasets to validate current GCM parameterizations for atmospheric GW drag and turbulence diffusion coefficients in the lower and middle atmospheres at southern high latitudes, increasing our understanding of these processes and their contribution to Antarctic circulation and climate.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.

科罗拉多大学、京都大学和东京国立极地研究所之间的这项国际合作将调查南极洲沿海大气湍流的来源。与地形对抗的强风会产生被称为大气重力波的波，当它们传播到更高的高度时，振幅会增加，变得不稳定，破裂，并引起湍流。湍流的另一个来源是大气中的剪切层，其中一层空气滑过另一层，导致开尔文-亥姆霍兹不稳定性。两者共同在天气预报模式中准确地表示南极气候方面发挥着重要作用。在这些遥远的南方高纬度地区收集新的湍流观测资料将改善南极气候的风和温度预报。该项目将在日本南极Syowa站的实地观测活动中，通过部署定制的高空气球系统，与强大的遥感雷达和多个长时间气球协调和合作，观测重力波和剪切引起的湍流动力学。当前的大气环流模式（GCM）参数化方案在很大程度上缺失了代表实际多尺度重力波（GW）阻力和Kelvin-Helmholtz不稳定性（KHI）动力学的源，以及它们对湍流输送/混合引起的动量和能量预算的贡献，从而导致南方高纬度天气尺度预报的退化。该项目利用高分辨率的原位湍流仪器来表征1)由变热强迫产生的地形型GWs， 2)由低压天气尺度事件产生的非地形型GWs，以及3)在南极沿海地区广泛尺度和背景环境中出现的KHI不稳定性。该项目将在南极洲东部的日本Syowa站部署数十个配备定制原位湍流和无线电探空仪器的低成本气球系统。气球有效载荷从20公里的远地点缓慢下降，在Syowa的PANSY雷达的部署指导下，与LODEWAVE长时间气球实验协调，提供高分辨率，无尾迹湍流观测。原位和遥感湍流观测的结合将量化与GWs和KHI相关的小尺度湍流大气过程的结构和动力学，这些过程被认为在极地环境中普遍存在，但很少观测到。在大范围尺度和背景环境下测量的动量通量和湍流耗散率将提供数据集，以验证当前GCM对南方高纬度地区大气GW阻力和湍流扩散系数的参数化，增加我们对这些过程及其对南极环流和气候的贡献的理解。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。