Dust and calcium record in calculated for ice core EPICA Dome C

Ice core data from Antarctica provide detailed insights into the characteristics of past climate, atmospheric circulation, as well as changes in the aerosol load of the atmosphere. We present high-resolution records of soluble calcium (Ca2+), non-sea-salt soluble calcium (nssCa2+), and particulate mineral dust aerosol from the East Antarctic Plateau at a depth resolution of 1 cm, spanning the past 800 000 years. Despite the fact that all three parameters are largely dust-derived, the ratio of nssCa2+ to particulate dust is dependent on the particulate dust concentration itself. We used principal component analysis to extract the joint climatic signal and produce a common high-resolution record of dust flux. This new record is used to identify Antarctic warming events during the past eight glacial periods. The phasing of dust flux and CO2 changes during glacial-interglacial transitions reveals that iron fertilization of the Southern Ocean during the past nine glacial terminations was not the dominant factor in the deglacial rise of CO2 concentrations. Rapid changes in dust flux during glacial terminations and Antarctic warming events point to a rapid response of the southern westerly wind belt in the region of southern South American dust sources on changing climate conditions. The clear lead of these dust changes on temperature rise suggests that an atmospheric reorganization occurred in the Southern Hemisphere before the Southern Ocean warmed significantly.

南极冰芯数据可细致揭示古气候特征、大气环流格局以及大气气溶胶负荷的演变规律。本研究提供了东南极高原过去80万年以来、深度分辨率达1厘米的高分辨率记录，涵盖可溶性钙（soluble calcium, Ca²⁺）、非海盐可溶性钙（non-sea-salt soluble calcium, nssCa²⁺）以及颗粒态矿物粉尘气溶胶（particulate mineral dust aerosol）三类指标。尽管上述三类参数均主要源自粉尘，但非海盐可溶性钙与颗粒态粉尘的比值本身取决于颗粒态粉尘的浓度。本研究采用主成分分析提取联合气候信号，并构建了一条统一的高分辨率粉尘通量记录。借助这一新的粉尘通量记录，我们识别出过去8个冰期阶段的南极变暖事件。冰期-间冰期转换阶段粉尘通量与二氧化碳（CO₂）浓度变化的相位关系表明，过去9次冰消期中南大洋的铁施肥作用并非二氧化碳浓度在冰消期上升的主导因素。冰消期与南极变暖事件期间粉尘通量的快速变化表明，南美南部粉尘源区周边的南半球西风带对气候条件变化存在快速响应。粉尘变化显著超前于温度上升这一现象表明，在南大洋显著变暖之前，南半球已发生大气环流重组。