Developing a Coarse-Grained Model to Investigate Long-Term Climate Behaviour

开发粗粒度模型来研究长期气候行为

• 批准号: 2445971
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2445971
• 关键词: Developing; Coarse; Grained; Model; Investigate

This project is looking at long term climatic behaviours with the intention of gaining insights into both past and future environmental changes. This relates to the LWEC research area of EPSRC as I will be investigating environmental effects that result from both orbital and geological phenomena, as well as the impact that humans have had.Earth's climate is constantly changing, with some changes taking millions of years and others just a decade. The current climate emergency, predominantly caused by significantly increased carbon dioxide emissions, has sparked an increased concern for the future of our climate. A global climate model (GCM) uses large datasets to make predictions about Earth's state with a timescale of the order of 100 years. GCMs are large-scale complex models that attempt to simulate the interacting behaviour of the oceans, atmosphere, cryosphere, biosphere and anthroposphere. Most current GCMs are highly tuned for accurate predictions over a decade timescale. These are important for vulnerable areas such as The Netherlands, with its flat, low altitude landscape, to prepare for climate events such as a rise in sea-level. There are also larger scale changes occurring, of the order of 100,000 years, most notably the regular glacial cycles or "ice ages". These changes may be relevant for short to medium term climate change but are not yet understood making them an important target for future research. The Milankovich cycles describe periodic variations to Earth's movement, including its axial tilt, varying with a period of 41, 000 years, and the eccentricity of its orbit, with a period of 100, 000 years. For the last million years, Earth's average temperature, and the surface area of its ice caps, has fluctuated with a reliable 100,000 year cycle. Although the consensus is that the eccentricity of Earth's orbit drives this climate variation, it is not entirely responsible. Before the last million years these climate cycles had a period of around 41,000 years, seemingly linked to Earth's axial tilt. Explaining this transition, from one periodicity to the other, is referred to as the '100,000 year problem' as it is not yet understood by climate scientists. Additionally, data shows that Earth's average temperature does not respond linearly to the Milankovich cycles suggesting that Earth has non-linear feedback mechanisms interacting with the Milankovich cycles. This PhD will explore and develop fundamental models of the whole-Earth system focusing on the known past behaviour the Earth's glacial cycles and possible future climate change on a 1,000 year timescale. The Budyko energy balance model developed in the 1950s provides a simple way to estimate the effect of parameters such as atmospheric CO2 concentration and the effect of the Milanovich cycles on global temperature over a timescale ranging from 1,000 to 1,000,000 years. Recently, Widiasih adapted the Budyko model to incorporate polar ice caps making it a candidate for investigating glacial cycles [3]. However, the resulting model does not reproduce the known past history of glacial cycles as the direct effect of the eccentricity cycle is too small to account for them. A possible explanation for this discrepancy is that the Budyko model treats the Earth as a homogeneous "waterworld" with both hemispheres being equivalent. The Earth is highly asymmetric with a significantly different distribution of land and ocean between the Northern and Southern hemispheres. Incorporating differential albedo between the hemispheres might account for the difference but will require reformulating the model from the beginning. The main objectives of this PhD are to develop novel models that can account for glacial cycles and use them to inform future predictions and improvements to GCMs. In particular: 1 Reformulate the Budyko model for an asymmetric Earth. A number of other extensions to the model are possible such as using the empirically observed albedo-larelationship.

该项目正在研究长期的气候行为，目的是洞悉过去和将来的环境变化。这与EPSRC的LWEC研究领域有关，因为我将调查轨道和地质现象均引起的环境影响，以及人类所产生的影响。Earth的气候正在不断变化，有些变化花费了数百万年，而另一些则仅仅是十年。当前的气候紧急情况主要是由二氧化碳排放量显着增加引起的，引发了人们对我们气候未来的关注。全球气候模型（GCM）使用大型数据集对地球状态进行预测，并以100年的时间尺度进行。 GCM是大规模复杂模型，试图模拟海洋，大气，冰冻圈，生物圈和人际的相互作用行为。在十年的时间范围内，大多数当前的GCM都经过高度调整以进行准确的预测。这些对于荷兰等脆弱的地区很重要，并具有平坦的低海拔景观，以准备诸如海平面上升的气候事件。还发生了更大的变化，即100，000年的阶段，最著名的是常规的冰川周期或“冰年龄”。这些变化可能与短期到中期气候变化有关，但尚未理解，使其成为未来研究的重要目标。米兰科维奇周期描述了地球运动的周期性变化，包括其轴向倾斜，随着41，000年的周期而变化，其轨道的偏心率为100，000年。在过去的百万年中，地球的平均温度及其冰盖的表面积随着可靠的100,000年周期波动。尽管共识是地球轨道的怪异驱动了这种气候变化，但它并不完全负责。在过去的百万年前，这些气候周期的时期约为41,000年，似乎与地球的轴向倾斜有关。从一个周期性到另一个周期性，解释这种过渡被称为“ 100,000年的问题”，因为气候科学家尚未理解。此外，数据表明，地球的平均温度对米兰科维奇周期没有线性响应，这表明地球具有与米兰科维奇周期相互作用的非线性反馈机制。该博士将探索和开发整体系统的基本模型，重点介绍了过去的冰川周期的已知行为，并在1000年的时间表上可能的未来气候变化。 1950年代开发的Budyko能量平衡模型提供了一种简单的方法来估计参数的影响，例如大气CO2浓度以及米兰诺维奇周期对全球温度的影响，范围从1,000至1,000，000年。最近，Widiasih对Budyko模型进行了改编，以结合极性冰盖，使其成为研究冰川周期的候选者[3]。但是，由于偏心周期的直接效应太小而无法解释它们，因此所产生的模型并未再现已知的过去历史。对这种差异的可能解释是，Budyko模型将地球视为同质的“水世界”，两个半球都是等效的。地球是高度不对称的，在北半球和南半球之间的土地和海洋分布显着不同。在半球之间纳入差异反照率可能是差异的原因，但需要从一开始就重新制定该模型。该博士学位的主要目标是开发可以解释冰川周期的新型模型，并使用它们为未来的GCMS预测和改进提供信息。特别是：1重新制定了不对称地球的Budyko模型。模型的许多其他扩展是可能的，例如使用经验观察到的反照率广告。