Climate Extremes in a Warmer World: What the Pliocene tell us?

极端天气和气候伴随着不利的社会经济影响，引起公众和决策者的极大兴趣。这些事件的盛行加剧了。北方野火的发生频率有所增加(例如，阿拉斯加和西伯利亚)。极端高温在东南亚和欧洲变得更加常见，而干旱在东非和南美更加常见。该项目将通过研究地球历史上的温暖气候状态，促进以新的视角研究水文和高温极端(例如，野火、热浪、干旱)。上新世中期暖期(约300万年前)是大气二氧化碳最后一次与现在(约400ppm)相媲美。研究表明，在上新世中期，全球气温比前工业时代高出5摄氏度。北冰洋季节性不结冰，北方森林延伸到北极海岸线，海平面比今天高出数米。鉴于丰富的地质证据和气候模型数据，上新世是国际古气候建模工作的关键焦点。该项目将使用一系列空间分辨率和复杂性范围的数值气候模型来研究中上新世期间的气候极端情况。这些结果将与极端气候观测趋势和不同温室气体排放/稳定情景下不久可能出现的极端气候的模拟结果进行比较。该项目有三个主要目标，利用历史观测为比较提供必要的基线：-分析上新世中期极端温度的地理分布、持续时间和频率，并将这些结果与未来的气候情景进行比较。-分析上新世中期水文极端事件(如干旱、高强度降雨事件)的地理分布、持续时间和频率，并将这些结果与未来气候情景进行比较。-阐明温度/水文极端与上新世期间发生/发生野火的地理可能性之间的关系。这将包括引用新的地质数据集，这些数据集记录了通过保存在多个陆地沉积物中的木炭层发生的野火。方法该项目将把现有的陆相上新世数据集与化石木炭赋存状态的新记录结合起来。它将使用利兹制作并通过国际上新世模型对比项目(PlioMIP)成员提供的气候模型输出，以调查高级别颗粒状气候数据(例如，每日-每月数据的统计分析)。学生将研究来自一组高分辨率纯大气模式(HadAM3H1.25x0.87o)模拟的气候数据(3小时)，以及一些有助于PlioMIP的世界最新气候和地球系统模型(例如，NCAR-CESM2和英国气象局-HadGEM3-AO)。

Weather and climate extremes, accompanied by adverse socio-economic impacts, are of great interest to the public and decision-makers. The prevalence of these events has intensified. Boreal wildfires have increased in frequency (e.g., Alaska and Siberia). Heat extremes have become more common in Southeast Asia and Europe, and droughts more common in East Africa and South America. This project will facilitate a novel perspective on hydrological and heat extremes (e.g., wildfire, heat waves, droughts) through the study of a warm climate state in Earth history. The mid-Pliocene Warm Period (~3 million years ago) was the last time atmospheric CO2 was comparable to present (~400 ppm). Studies indicate that the during the mid-Pliocene global temperatures were up to 5oC warmer than the pre-industrial era. The Arctic Ocean was seasonally ice-free, boreal forests reached the Arctic coastline and sea level was metres higher than it is today. Given a rich body of geological evidence, and climate model data the Pliocene is a key focus for international palaeoclimate modelling efforts.This project will investigate climate extremes during the mid-Pliocene using a spectrum of numerical climate models, that range in spatial resolution and complexity. These outcomes will be compared to both observational trends in climate extremes and simulations of plausible climate extremes of the near future under different greenhouse gas emission/stabilisation scenarios. The project has three main objectives using historical observations to provide the necessary baseline for comparison:- Analyse the geographical distribution, duration, and frequency of temperature extremes during the mid-Pliocene and compare these results to future climate scenarios. - Analyse the geographical distribution, duration, and frequency of hydrological extremes (e.g., droughts, high intensity rainfall events) during the mid-Pliocene and compare these results to future climate scenarios. - Elucidate the relationship between temperature/hydrological extremes and the geographical occurrence/likelihood of wildfires during the Pliocene. This will include reference to new geological data sets documenting wildfire occurrence through charcoal layers preserved in multiple terrestrial deposits. MethodsThe project will combine existing datasets of terrestrial Pliocene data with new records of fossil charcoal occurrence. It will use climate model outputs produced at Leeds and provided via members of the international Pliocene Model Intercomparison Project (PlioMIP), to investigate high-level granular climate data (e.g., statistical analysis of daily-monthly data). The student will examine climate data (3-hrly) from a set of high-resolution Atmosphere-only model (HadAM3H 1.25 x 0.87o) simulations as well as some of the worlds very latest climate and Earth System Model contributing to PlioMIP (e.g., NCAR - CESM2 & UK Met Office - HadGEM3-AO).