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

若干气候模式表明，未来变暖的气候可能导致降水增加，北非亚热带地区可能变绿，空气中粉尘负荷减少，高纬度地区植树造林。植被覆盖和沙尘最近都被强调为主要的气候强迫，能够影响大尺度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，因此我们仍然缺乏对这些复杂相互作用的透彻理解，这些相互作用在模式模拟中经常被忽略。***在过去的气候中，植被覆盖和粉尘排放发生了巨大的变化，这为我们提供了一个独特的机会，可以提高我们对它们在改变气候方面的作用的理解。例如，在非洲湿润期（AHP，距今11 - 5年），今天极度干旱的撒哈拉沙漠变成了一片郁郁葱葱的草地。然而，这种转变的确切机制可能是突然的，也可能不是突然的，以及来自尘埃和植被变化的反馈的作用仍然是一个悬而未决的问题。考虑到AHP期间经历的如此大的植被和沙尘负荷变化，这一时期是我们对辐射强迫与大气环流相互作用机制理解的一个很好的测试案例。这一时期将使我们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，它将提供机会来检查大尺度和区域气候变化之间的联系，这些变化引起了诸如陆海对比、高纬度温度放大以及季风的盛衰等现象。***本研究计划的长期目标是推动科学发展，使我们能够结合综合数据、数值气候模拟和统计模型等方法，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。***短期目标是：1)系统评估不同地理区域的沙尘和植被覆盖变化对本地和全球气候（过去和未来）探测的影响；2)通过发展AD hoc模型敏感性研究来探讨相关的归因机制；3)利用新的古气候重建和模式模拟来改进非洲西北部近20年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，以了解它们对解剖学上的现代人在非洲大陆扩散的潜在影响。

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.