Using aviation meteorology to improve aircraft safety

航空气象学是一门了解、预测和减少这些危险的科学，以提高飞行安全。有证据表明，由于气候变化，闪电和湍流将变得更加普遍，这增加了我们对这些危害的理解的必要性。许多在北海石油和天然气领域工作的直升机被闪电击中，其中一些遭遇了特别具有破坏性的正面袭击。在一个典型的冬季，北海作业区域大约有10次冷空气爆发，每次持续约三天，这意味着每个季节通常有30个罢工风险日。雷击可造成重大损害，立即引发紧急情况，并要求直升机停止服务进行维护和维修。大气条件和雷击之间的详细关系目前还不太确定。此外，全球每年都有数千架飞机遭遇严重的湍流。湍流不仅会伤害乘客和机组人员，还会对飞机造成结构损坏。乱流每年造成的经济损失达数亿美元。根据事故和事件调查，遭遇垂直和水平高空风切变（与湍流有关）有时会违反飞机的认证信封。现有的操作湍流预测算法产生了很大一部分遗漏事件和误报。这反映了我们对湍流的成因及其与大气条件的关系的了解不足，表明通过有针对性的研究提高预报的准确性还有很大的余地。这个项目将提高我们对影响航空的湍流和闪电及其与大气条件的关系的科学认识。英国民航局（Civil Aviation Authority，简称CAA）自20世纪70年代以来的数十万起事故和事件的数据库将被挖掘出来，以隔离涉及湍流或闪电的事件。对于每个事件，将根据再分析数据（例如ERA-Interim）确定时间、日期和地点的大气条件。将计算各种提出的晴空湍流诊断方法（如埃尔罗德指数、位涡度、理查德森数）、对流湍流（如对流有效势能（CAPE）和其他对流诊断产品）和闪电（如最大云高度的五次方，CAPE乘以降水率）。通过在特定诊断的统计气候学直方图中确定它们对应的百分位数，将检验它们代表观测事件的能力。该项目的第二个方面将是考虑气候变化的影响。在使用网格化再分析数据确定了CAA数据库中最擅长诊断事件的诊断方法后，将根据网格化气候模式模拟计算这些诊断方法。在适当的温室气体情景下，将确定诊断方法在不同海拔和地理区域以及不同季节的长期趋势。该项目将使人们更好地了解(i)影响航空的湍流和闪电与大尺度大气条件的关系，以及（ii）影响航空的湍流和闪电对气候变化的响应。

Aviation meteorology is the science of understanding, predicting, and minimizing the risks from these hazards, to improve flight safety. There is evidence that both lightning and turbulence will become more common because of climate change, increasing the need to improve our understanding of these hazards.Many helicopters working in the North Sea oil and gas sector have been struck by lightning, some encountering positive strikes that are especially destructive. In a typical winter season, there are about 10 cold-air outbreaks in the North Sea operating area, each lasting around three days, meaning there are typically 30 strike risk days per season. Lightning strikes can cause substantial damage, immediately prompting an emergency and requiring the helicopter to be taken out of service for maintenance and repairs. The detailed relationship between atmospheric conditions and lightning strikes is currently poorly established.In addition, thousands of planes encounter potentially hospitalizing severe turbulence globally each year. As well as injuring passengers and crew, turbulence can also cause structural damage to aircraft. The economic cost of turbulence is several hundred million dollars annually. Encounters with vertical and horizontal high-altitude wind shear - which is associated with turbulence - sometimes currently infringe aircraft certification envelopes, according to accident and incident investigations. Existing operational turbulence prediction algorithms generate a significant fraction of missed events and false positives. This reflects our poor understanding of the causes of turbulence and its relationship to atmospheric conditions, suggesting considerable scope to improve the accuracy of the forecasts through targeted research.This project will improve our scientific understanding of aviation-affecting turbulence and lightning and their relationship to atmospheric conditions. The Civil Aviation Authority's (CAA's) database of several hundred-thousand accidents and incidents since the 1970s will be mined to isolate events involving turbulence or lightning. For each event, the atmospheric conditions at the time, date, and location will be determined from reanalysis data (e.g. ERA-Interim). Various proposed diagnostics of clear-air turbulence (e.g., Ellrod's index, potential vorticity, Richardson number), convective turbulence (e.g., convective available potential energy (CAPE) and other convective diagnostic products), and lightning (e.g., maximum cloud height to the fifth power, CAPE multiplied by precipitation rate) will be calculated. Their ability to represent the observed event will be tested by identifying which percentile they correspond to, in a histogram of the statistical climatology of the particular diagnostic.A second strand to the project will be to consider the effects of climate change. Having identified which diagnostics are most skillful at diagnosing events in the CAA database using the gridded reanalysis data, those diagnostics will be calculated from gridded climate model simulations. Under a suitable greenhouse gas scenario, long-term trends in the diagnostics will be identified at different altitudes and geographic regions and in different seasons.The project will result in an improved understanding of (i) the relationship of aviation-affecting turbulence and lightning to large-scale atmospheric conditions, and (ii) the response of aviation-affecting turbulence and lightning to climate change.