Dust Impact and Vegetation Influence on CLIMate: looking to the future from a paleo perspective (DiViCLIM)

灰尘影响和植被对 CLIMate 的影响：从古角度展望未来 (DiViCLIM)

• 批准号: RGPIN-2018-04981
• 负责人: Pausata, FrancescoSalvatoreRocco
• 金额: $ 2.19万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=713429
• 关键词: Dust; Impact; Vegetation; Influence; CLIMate

Several climate models suggest that a future warmer climate may lead to an increase in precipitation and a potential greening of the subtropical North Africa, a reduction in airborne dust loadings, and afforestation of high latitudes. Both vegetation cover and dust were recently highlighted as major climate forcings, able to affect large-scale atmospheric circulation and its modes of variability, such as the monsoons, the El Nino-Southern Oscillation, the tropical cyclone activity and the Arctic climate. However, at present few studies are yet available on the implication of vegetation and dust changes on regional and global climate, and therefore we still lack a thorough understanding of these complex interactions that are often neglected in model simulations. Past climates, during which large changes in vegetation cover and dust emission occurred, offer a unique opportunity to improve our understanding of their role on altering climate. For example, during the African Humid Period (AHP, 11 - 5 kyrs BP), the today's hyper arid Sahara desert was transformed into a lush expanse of grass. However, the exact mechanisms involved in this transition, which may or may have not been abrupt, and the role of feedbacks from dust and vegetation changes are still open questions. Given such large vegetation and dust loading changes experienced during the AHP, this period is a good test case of our mechanistic understanding of the interplay between radiative forcing and atmospheric circulation. This period will allow to clearly detect the most important geographical regions that are able to play a larger role in affecting global climate. It will then provide opportunities to examine connections among large-scale and regional climate changes, which give rise to phenomena, such as land-sea contrast, high-latitude temperature amplification, and the waxing and waning of the monsoons. The long-term goal of this research program is to advance the science that will allow us to anticipate the climate consequences associated with aerosol-land-cover changes-climate interactions, combining methods that involve the synthesis of data, numerical climate simulations, and statistical models. The short-term objectives are 1) to systematically assess the impact of dust and vegetation cover changes in different geographical regions in affecting local and global climate (past and future) detection; 2) to investigate the associated mechanisms at play attribution through the development of ad hoc model sensitivity studies; 3) to use new paleoclimate reconstructions and model simulations to improve the interpretation of marine sediment core reconstructions of the last 20 kyrs from northwestern Africa; 4) to quantify the changes in the environmental condition in central and southern Africa to understand their potential influence on the dispersal of anatomically modern humans within the African continent.

一些气候模型表明，未来气候变暖可能会导致降水增加，北非亚热带地区可能出现绿化，空气中尘埃含量减少，以及高纬度地区的植树造林。最近，植被覆盖和灰尘都被强调为主要的气候强迫，能够影响大规模的大气环流及其变化模式，例如季风、厄尔尼诺南方涛动、热带气旋活动和北极气候。然而，目前关于植被和沙尘变化对区域和全球气候影响的研究还很少，因此我们对这些在模型模拟中经常被忽视的复杂相互作用仍然缺乏透彻的了解。 过去的气候，植被覆盖和灰尘排放发生了巨大的变化，为我们提供了一个独特的机会来加深我们对它们在改变气候中的作用的理解。例如，在非洲湿润期（AHP，距今11 - 5 kyrs），今天极度干旱的撒哈拉沙漠变成了一片茂密的草地。然而，这种转变所涉及的确切机制（可能是突然的，也可能不是突然的），以及灰尘和植被变化的反馈的作用仍然是悬而未决的问题。鉴于 AHP 期间经历了如此大的植被和灰尘负荷变化，这一时期是我们对辐射强迫和大气环流之间相互作用的机械理解的一个很好的测试案例。这一时期将能够清楚地发现能够在影响全球气候方面发挥更大作用的最重要的地理区域。然后，它将提供机会来研究大规模和区域气候变化之间的联系，这些变化引起了陆地与海洋对比、高纬度温度放大以及季风盛衰等现象。 该研究计划的长期目标是推进科学发展，使我们能够结合数据综合、数值气候模拟和统计方法来预测与气溶胶-土地覆盖变化-气候相互作用相关的气候后果。模型。 短期目标是1）系统评估不同地理区域的灰尘和植被覆盖变化对当地和全球气候（过去和未来）检测的影响； 2) 通过开发特别模型敏感性研究来调查起作用归因的相关机制； 3) 使用新的古气候重建和模型模拟来改进对非洲西北部最近 20 公里海洋沉积物岩心重建的解释； 4）量化非洲中部和南部环境条件的变化，以了解其对非洲大陆解剖学上的现代人类扩散的潜在影响。