Improving Understanding and Diagnosis of Jet-Stream Turbulence

提高对急流湍流的理解和诊断

• 批准号: NE/W000997/1
• 负责人: David Schultz
• 金额: $ 76.8万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW000997%2F1
• 关键词: Improving; Understanding; Diagnosis; Jet; Stream

Turbulence is the leading cause of weather-related aircraft incidents and the underlying cause of many people's fear of air travel. One estimate of turbulence indicates over 63,000 encounters with moderate-or-greater turbulence and 5000 encounters with severe-or-greater turbulence annually. In 34 years, the US reported 883 fatalities associated with turbulence. Turbulence can also damage aircraft, by tearing off winds and engines, as happened in an extreme turbulent event over Colorado in 1992. The economic costs of turbulence are more than just injuries and damage, with flight delays, inspections, repairs, and post-accident investigations also taking their toll. Estimates of the total cost to US carriers alone are nearly $200 million annually. Although the costs of turbulence to UK/EU airlines and over EU airspace are not available, assuming the occurrence of turbulence and the density of air travel are similar to that over the US and that the EU is about the same size as the US, then costs should be comparable.Moreover, climate change is exacerbating the problem. Midlatitude turbulence diagnosed from climate projections increase under increasing atmospheric carbon dioxide, with a doubling or trebling later this century. Thus, the costs of turbulence due to climate change will lead to a substantial increase in turbulent events. Clear-air turbulence, abbreviated as CAT, is turbulence that occurs away from clouds in clear air. CAT is difficult for pilots to detect and for forecasters to predict. One of the reasons that it is difficult to predict is that CAT is believed to have multiple sources and no single forecasting tool works for all of the sources. One suspected source of CAT is the release of hydrodynamic instability, an imbalance between different forces in the atmosphere that lead to large and rapid accelerations of the air. Such accelerations may produce atmospheric phenomena such as roll-type circulations or wave-like motions that result in CAT. Presently, we have an incomplete understanding of how hydrodynamic instability forms, releases, produces turbulence, and returns to stability. In this proposed research, we will look at observations of turbulence from three sources. One is from a vertically pointing radar in Wales that can detect turbulence at the jet stream. A second one is from pilots manually reporting turbulence. A third is from automated instrumentation aboard aircraft. We will use these observations to understand the conditions in which CAT forms and its relationship to hydrodynamic instability. Because these observations are snapshots in time from single measurements, computer model simulations of real and idealised weather phenomena that produce CAT will be critical to determine how the instability forms, how the instability and resulting turbulence evolves, and how the atmosphere returns to balance after the release of the instability. Within the context of the results from the observations, we will construct the life cycle of CAT from its origin, to its growth, to its demise. Given these new insights, we will develop tools for model output (called diagnostics) to quantify the impacts from the release of the instability and evaluate the performance of these diagnostics over North America, the North Atlantic Ocean, and Europe. In this way, improved understanding of the CAT life cycle will lead to better predictions of jet-stream turbulence, as well as reduced costs and injuries to passengers and flight crew.

湍流是与天气相关的飞机事故的主要原因，也是许多人害怕航空旅行的根本原因。对湍流的一项估计表明，每年有超过 63,000 次遭遇中度或较大湍流，以及 5000 次遭遇严重或较大湍流。 34 年来，美国报告了 883 人因湍流死亡。湍流还会损坏飞机，因为风和发动机会被撕裂，就像 1992 年科罗拉多州发生的一场极端湍流事件一样。湍流的经济成本不仅仅是人员伤亡和损坏，还包括航班延误、检查、维修和事故后的损失。调查也造成了损失。据估计，仅美国运营商每年的总成本就接近 2 亿美元。尽管无法获得英国/欧盟航空公司和欧盟空域的湍流成本，但假设湍流的发生和航空旅行的密度与美国相似，并且欧盟的面积与美国大致相同，那么成本应该具有可比性。此外，气候变化正在加剧这一问题。根据气候预测诊断出的中纬度湍流随着大气中二氧化碳的增加而增加，本世纪后期增加了一倍或三倍。因此，气候变化造成的湍流成本将导致湍流事件的大幅增加。晴空湍流，缩写为CAT，是指在晴朗空气中远离云层发生的湍流。 CAT 飞行员很难发现，预报员也很难预测。难以预测的原因之一是 CAT 被认为有多个来源，并且没有一个预测工具适用于所有来源。 CAT 的一个可疑来源是流体动力学不稳定性的释放，即大气中不同力之间的不平衡，导致空气大幅快速加速。这种加速度可能会产生大气现象，例如导致 CAT 的滚转型环流或波状运动。目前，我们对流体动力学不稳定性如何形成、释放、产生湍流以及恢复稳定的了解还不完全。在这项拟议的研究中，我们将从三个来源观察湍流。其中之一来自威尔士的垂直指向雷达，可以探测急流的湍流。第二个来自飞行员手动报告湍流。第三个来自飞机上的自动化仪表。我们将利用这些观察结果来了解 CAT 形成的条件及其与流体动力学不稳定性的关系。由于这些观测结果是单次测量的及时快照，因此产生 CAT 的真实和理想天气现象的计算机模型模拟对于确定不稳定性如何形成、不稳定性和由此产生的湍流如何演变以及大气在释放不稳定因素。在观察结果的背景下，我们将构建 CAT 从起源、生长到消亡的生命周期。鉴于这些新见解，我们将开发模型输出工具（称为诊断），以量化不稳定因素释放的影响，并评估这些诊断在北美、北大西洋和欧洲的性能。通过这种方式，加深对 CAT 生命周期的了解将有助于更好地预测急流湍流，并减少乘客和机组人员的成本和伤害。

项目成果

Climatology of Large Hail in Europe: Characteristics of the European Severe Weather Database

欧洲大冰雹的气候学：欧洲灾害性天气数据库的特征

• DOI: http://dx.10.5194/egusphere-2023-176
• 发表时间: 2023
• 作者: Hulton F

Five-Year Climatology and Composite Study of Precipitation Bands Associated with Extratropical Cyclones over the British Isles

与不列颠群岛温带气旋相关的降水带的五年气候学和综合研究

• DOI: http://dx.10.1175/waf-d-22-0207.1
• 发表时间: 2023
• 期刊: Weather and Forecasting
• 影响因子: 2.9
• 作者: Zhang T

Weather Effects on the Spread of COVID-19: Characteristics and Critical Analysis of the First and Second Years of Scientific Research

天气对 COVID-19 传播的影响：科学研究第一年和第二年的特征和批判性分析

• DOI: http://dx.10.1175/bams-d-23-0071.1
• 发表时间: 2023
• 期刊: Bulletin of the American Meteorological Society
• 影响因子: 8
• 作者: Tan L