Cruz Juncal A, McDermott Frank, Turrero María J, Edwards R Lawrence, Martín-Chivelet Javier
Department of Geodynamics, Stratigraphy, and Paleontology, Faculty of Geological Sciences, Complutense University of Madrid, Madrid, Spain.
UCD School of Earth Sciences and Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland.
Sci Adv. 2021 Jun 25;7(26). doi: 10.1126/sciadv.abe6102. Print 2021 Jun.
Despite the multiple impacts of mineral aerosols on global and regional climate and the primary climatic control on atmospheric dust fluxes, dust-climate feedbacks remain poorly constrained, particularly at submillennial time scales, hampering regional and global climate models. We reconstruct Saharan dust fluxes over Western Europe for the last 5000 years, by means of speleothem strontium isotope ratios (Sr/Sr) and karst modeling. The record reveals a long-term increase in Saharan dust flux, consistent with progressive North Africa aridification and strengthening of Northern Hemisphere latitudinal climatic gradients. On shorter, centennial to millennial scales, it shows broad variations in dust fluxes, in tune with North Atlantic ocean-atmosphere patterns and with monsoonal variability. Dust fluxes rapidly increase before (and peaks at) Late Holocene multidecadal- to century-scale cold climate events, including those around 4200, 2800, and 1500 years before present, suggesting the operation of previously unknown strong dust-climate negative feedbacks preceding these episodes.
尽管矿物气溶胶对全球和区域气候有多种影响，且大气尘埃通量主要受气候控制，但尘埃-气候反馈仍受限制，尤其是在亚千年时间尺度上，这阻碍了区域和全球气候模型的发展。我们通过洞穴石笋锶同位素比率（Sr/Sr）和岩溶模型重建了过去5000年西欧上空的撒哈拉尘埃通量。该记录显示撒哈拉尘埃通量呈长期增加趋势，这与北非逐渐干旱化以及北半球纬度气候梯度增强相一致。在较短的百年至千年尺度上，尘埃通量呈现出广泛变化，与北大西洋海洋-大气模式和季风变化一致。尘埃通量在全新世晚期数十年至世纪尺度的寒冷气候事件之前迅速增加（并在这些事件中达到峰值），包括距今约4200年、2800年和1500年左右的事件，这表明在这些事件之前存在此前未知的强烈尘埃-气候负反馈机制。
