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

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.

来自南极的冰芯数据（ice core data）可为过去气候特征、大气环流以及大气气溶胶载荷变化提供详尽的解析。本研究报道了采自东南极高原（East Antarctic Plateau）的高分辨率数据集，其以1厘米为深度分辨率（depth resolution），覆盖过去80万年，包含可溶性钙（soluble calcium, Ca²+）、非海盐可溶性钙（non-sea-salt soluble calcium, nssCa²+）与颗粒矿物粉尘气溶胶（particulate mineral dust aerosol）的相关记录。尽管三类参数均主要源于粉尘，但非海盐可溶性钙与颗粒粉尘的比值本身取决于颗粒粉尘的浓度。本研究采用主成分分析（Principal Component Analysis）提取共同气候信号，构建了统一的粉尘通量高分辨率记录。借助这一新记录，我们识别了过去8个冰期（glacial periods）阶段中的南极暖化事件。冰期-间冰期转换（glacial-interglacial transitions）阶段粉尘通量与二氧化碳（carbon dioxide, CO₂）变化的相位关系显示，过去9次冰消期（glacial termination）过程中南大洋（Southern Ocean）的铁肥化作用（iron fertilization）并非二氧化碳浓度冰消期抬升的主导因素。冰消过程与南极暖化事件中粉尘通量的快速变化表明，南美南部粉尘源区周边的南西风带（southern westerly wind belt）对气候条件变化存在快速响应。这些粉尘变化早于温度上升的显著特征表明，在南大洋显著暖化之前，南半球已发生了大气环流重组（atmospheric reorganization）。