Extratropical Climate Change in the Upper Troposphere and the Routing of Aircraft (EXTRA)

对流层上层的温带气候变化和飞机航线（EXTRA）

基本信息

批准号：
NE/J021113/1
负责人：
Keith Shine
金额：
$ 36.77万
依托单位：
University of Reading
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ021113%2F1
关键词：
Extratropical Climate Change Upper Troposphere

项目摘要

The upper troposphere in mid-latitudes is the region encompassing altitudes of around 8-12 km, which includes the jet streams, regions of very strong winds, which are closely related to strengths and paths of the mid-latitude depressions. Climate change is expected to change the nature of the upper troposphere at mid-latitudes - climate models indicate that over coming decades, it will warm, the relative humidity will increase and the strength and orientation of the jet stream might change, and the boundary between the troposphere and the overlying stratosphere (the tropopause) will increase in altitude. However, when different climate models are used to predict future climate change, there is a significant spread in the results they produce; the reasons for this spread are not fully understood.Understanding climate change in the mid-latitude upper troposphere is of importance in its own right, but it has a wider economic significance. The cruise altititude of commercial aircraft is in the upper troposphere and flight times can be strongly affected by the wind conditions. Most obviously, the duration of flights between (as an example) London and New York are normally more than an hour faster when going eastbound, as the aircraft attempt to fly in the jet stream and receive an extra "push" - by contrast, westbound flights normally try to avoid the jet stream as this would impede progress. However, day-to-day variations in weather conditions in the north Atlantic mean that flight durations of both eastbound and westbound flights can vary by up to 100 minutes, depending largely on the strength and position of the jet stream. Since fuel use, and hence carbon dioxide emissions, are closely related to the flight duration, there are both economic and climate consequences for this variation. In our recent research we have shown that the weather in the upper troposphere in the North Atlantic can be split into characeristic patterns (5 in winter and 3 in summer) for which the aircraft routes are distinct. In addition we have shown that other climate effects of aircraft emissions (for example, contrails and ozone change resulting from emissions of oxides of nitrogen) very likely vary between these weather patterns.Since aircraft routing is dependent on the weather situation in the upper troposphere, it is natural to ask whether climate change could impact on aircraft routing. There has been much research on the effect of aviation on climate change, but surprisingly little that asks the reverse question: what is the effect of climate change on aviation? Our proposal aims to answer this question, while at the same time improving understanding of upper tropospheric climate change. Since the aviation industry aims to put constraints on its carbon dioxide emissions, the effect of climate change on aviation routing could either assist or work against these aims. We will consider how the routes of individual aircraft may be affected by the changes in the frequency of different weather patterns in the North Atlantic, predicted by a number of different climate models. We will exploit a recent, large and easily available set of simulations of possible future climate change from a range of world-leading climate models that have been produced for the fifth assessment report of the Intergovernmental Panel on Climate Change, which is currently being written. We will assess how well the climate models reproduce the present-day weather patterns in the North Atlantic and then look at how these patterns change for various possible future climates. We will then see how aircraft routing is affected by these weather patterns and compute the impact of this carbon dioxide emissions. We will also investigate the impact of both the climate change and re-routing on the other climate impacts of aviation.We will extend this work to cover the North Pacific, which is expected to show a significant increase in air traffic over coming decades.

中纬度对流层上层是指海拔8~12公里左右的区域，其中包括急流、强风区，与中纬度低气压的强度和路径密切相关。气候变化预计将改变中纬度地区对流层上层的性质——气候模型表明，在未来几十年里，气候将会变暖，相对湿度将会增加，急流的强度和方向可能会发生变化，而对流层之间的边界也会发生变化。对流层和平流层（对流层顶）的高度将会增加。然而，当使用不同的气候模型来预测未来的气候变化时，它们产生的结果存在显着的差异；这种传播的原因尚不完全清楚。了解中纬度对流层上层的气候变化本身就很重要，但它具有更广泛的经济意义。商用飞机的巡航高度位于对流层上层，飞行时间会受到风力条件的强烈影响。最明显的是，（例如）伦敦和纽约之间的航班在东行时通常会快一个多小时，因为飞机试图在急流中飞行并受到额外的“推力” - 相比之下，西行航班通常会尽量避开急流，因为这会阻碍进展。然而，北大西洋天气状况的日常变化意味着东行和西行航班的飞行时间可能相差最多 100 分钟，这在很大程度上取决于急流的强度和位置。由于燃料使用以及二氧化碳排放与飞行时间密切相关，因此这种变化会产生经济和气候后果。在我们最近的研究中，我们表明，北大西洋对流层上层的天气可以分为不同的特征模式（冬季 5 种，夏季 3 种），飞机航线也各不相同。此外，我们还表明，飞机排放的其他气候影响（例如，氮氧化物排放导致的尾迹和臭氧变化）很可能在这些天气模式之间有所不同。由于飞机航线取决于对流层上层的天气状况，人们自然会问气候变化是否会影响飞机航线。关于航空对气候变化的影响已经有很多研究，但令人惊讶的是很少有人提出相反的问题：气候变化对航空有什么影响？我们的提案旨在回答这个问题，同时增进对对流层上层气候变化的理解。由于航空业的目标是限制二氧化碳排放，气候变化对航空路线的影响可能有助于实现这些目标，也可能不利于实现这些目标。我们将考虑北大西洋不同天气模式的频率变化如何影响个别飞机的航线，这些天气模式是由许多不同的气候模型预测的。我们将利用一系列世界领先的气候模型对未来可能发生的气候变化进行一组最新的、大量的、易于获得的模拟，这些模型是为目前正在撰写的政府间气候变化专门委员会第五次评估报告而制作的。我们将评估气候模型在多大程度上再现了北大西洋当前的天气模式，然后研究这些模式如何随着未来各种可能的气候而变化。然后，我们将了解这些天气模式如何影响飞机航线，并计算二氧化碳排放的影响。我们还将调查气候变化和重新航线对航空的其他气候影响的影响。我们将把这项工作扩展到北太平洋，预计未来几十年航空交通量将显着增加。