Causes of change in European mean and extreme climate over the past 500 years

过去500年欧洲平均和极端气候变化的原因

基本信息

批准号：
NE/G019819/1
负责人：
Gabriele Hegerl
金额：
$ 39.31万
依托单位：
University of Edinburgh
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG019819%2F1
关键词：
Causes change European mean extreme

项目摘要

The aim of our project is to understand the causes of variability and change in mean and extreme temperature, and changes in mean precipitation over the last 500 years, largely focusing on Europe. Spatial patterns of climate change and changes in extremes are important since climate affects society and the natural world on regional scales. By understanding why temperature and temperature extremes as well as precipitation have varied in the past, we will be better able to predict how it might vary in the future. This will be because we will have improved our knowledge of what mechanisms were important in changes in the past, and tested the ability of climate models to reproduce what has happened in the past. Researchers have reconstructed European temperature variability over the last 500 years, and long homogenized instrumental records are now available that go back into the 18th century, and in some cases have daily resolution. Also, some reconstructions of precipitation and circulation are becoming available that go back reliably about 250 years, and with more limitations, 500 years. Other investigators have reconstructed changes in solar activity, the timing and magnitude of major volcanic eruptions and the composition of the atmosphere using data recorded in the ice sheets. The most important natural 'forcing' of climate has been thought to be changes in radiation from the Sun. This is reconstructed from measures of solar activity such as sunspots. However, another possibly more important climate forcing is the effect of large explosive volcanic eruptions. These inject sulphate aerosol into the upper atmosphere, which reflect more sunlight, causing cooling. Since the 18th and 19th centuries human forcings have become important. Human emissions of carbon dioxide and other greenhouse gases are well mixed, so cause roughly equal warming everywhere. From the 18th century on substantial deforestation took place. The removal of forest makes the land reflect more sunlight back to space, causing a cooling. The main fossil fuel burnt in the 19th century was coal, whose burning causes sulphur to be emitted to the atmosphere. The sulphur forms a short-lived aerosol which acts to cool regions close to where it is emitted. Thus, human forcings would be expected to have a rather complex regional affect with, in the Northern Hemisphere, warming from greenhouse gases being, partly to fully, offset by cooling due to deforestation and aerosols. To find causes of the observed patterns of climate change over Europe and the Northern hemisphere we will use climate models that can simulate what would have happened due to each individual 'forcing' described above. Then using mathematical techniques we will compare these 'fingerprints' with reconstructions of past climate change and climate variability and determine which changes have been caused by external influences, and which are just a representation of a naturally varying climate. We will mainly focus on patterns of temperature and precipitation change over Europe since 1500, but also explore the causes of changes over the entire millennium. The results of the comparison tell us the relative contribution of each forcing to past climate change, and how much change is left unexplained and may have occurred spontaneously due to chaotic variability in the climate. Since climate models, like the real world, have chaotic variability, we will use several simulations to isolate the predictable component. Using models and reconstructions, we will also explore the mechanisms responsible for the historical changes.

我们项目的目的是了解过去500年来平均温度和极端温度变化的原因，平均降水量的变化，主要集中在欧洲。气候变化和极端变化的空间模式很重要，因为气候在区域范围内影响社会和自然世界。通过了解为什么过去的温度和温度极端和降水在过去有所不同，我们将能够更好地预测未来的变化。这是因为我们将提高我们对过去变化中哪些机制重要的了解，并测试了气候模型重现过去发生的事情的能力。在过去的500年中，研究人员已重建了欧洲温度的变化，现在可以使用长期均质的仪器记录，可以追溯到18世纪，在某些情况下可以每天解决。同样，一些降水和循环的重建正在可靠地可靠地返回250年，并且有更多的限制（500年）。其他研究人员使用记录的冰盖中记录的数据重建了太阳能活动的变化，主要火山喷发的时间和幅度以及大气组成。人们认为最重要的自然“强迫”是从太阳辐射的变化。这是从太阳活动（例如黑子）的测量中重建的。但是，另一个可能更重要的气候强迫是大型爆炸性火山喷发的影响。这些将硫酸盐气溶胶注入上层大气中，这反映了更多的阳光，从而导致冷却。自18世纪和19世纪以来，人类强迫变得很重要。二氧化碳和其他温室气体的人类排放良好，因此到处都大致相等。从18世纪开始，进行了实质性的森林砍伐。森林的去除使土地反射到更大的阳光回太空，从而导致冷却。 19世纪的主要化石燃料是煤炭，其燃烧使硫散发到大气中。硫形成短寿命的气溶胶，可用于靠近其发射的冷却区域。因此，在北半球，人类的强迫将产生相当复杂的区域影响，从温室气体变暖，部分是由于森林砍伐和气雾剂而被冷却所抵消。为了找到欧洲和北半球的气候变化模式的原因，我们将使用气候模型，这些模型可以模拟由于上述每个人的“强迫”而导致的情况。然后，我们将使用数学技术将这些“指纹”与过去气候变化和气候变化的重建进行比较，并确定哪些变化是由外部影响引起的，哪些只是自然变化的气候的代表。自1500年以来，我们将主要关注欧洲温度和降水变化的模式，但也探讨了整个千年中变化的原因。比较结果告诉我们，每种强迫对过去气候变化的相对贡献，以及由于气候中混乱的变化而无法解释的变化，可能是自发发生的。由于像现实世界一样，气候模型具有混乱的可变性，因此我们将使用几个模拟来隔离可预测的组件。使用模型和重建，我们还将探索负责历史变化的机制。