(Table 4) Seasonal variation of sea spray sodium concentrations during 2004-2007 at Concordia Station, Antarctica

From November 2004 to December 2007, size-segregated aerosol samples were collected all-year-round at Dome C (East Antarctica) by using PM10 and PM2.5 samplers, and multi-stage impactors. The data set obtained from the chemical analysis provided the longest and the most time-resolved record of sea spray aerosol (sea salt Na+) in inner Antarctica. Sea spray showed a sharp seasonal pattern. The highest values measured in winter (Apr-Nov) were about ten times larger than in summer (Dec-Mar). For the first time, a size-distribution seasonal pattern was also shown: in winter, sea spray particles are mainly submicrometric, while their summer size-mode is around 1-2 µm. Meteorological analysis on a synoptic scale allowed the definition of atmospheric conditions leading sea spray to Dome C. An extreme-value approach along with specific environmental based criteria was taken to yield stronger fingerprints linking atmospheric circulation (means and anomalies) to extreme sea spray events. Air mass back-trajectory analyses for some high sea spray events allowed the identification of two major air mass pathways, reflecting different size distributions: micrometric fractions for transport from the closer Indian-Pacific sector, and sub-micrometric particles for longer trajectories over the Antarctic Plateau. The seasonal pattern of the SO4**2- /Na+ ratio enabled the identification of few events depleted in sulphate, with respect to the seawater composition. By using methanesulphonic acid (MSA) profile to evaluate the biogenic SO4**2- contribution, a more reliable sea salt sulphate was calculated. In this way, few events (mainly in April and in September) were identified originating probably from the \"frost flower\" source. A comparison with daily-collected superficial snow samples revealed that there is a temporal shift between aerosol and snow sea spray trends. This feature could imply a more complex deposition processes of sea spray, involving significant contribution of wet and diamond dust deposition, but further work has to be carried out to rule out the effect of wind re-distribution and to have more statistic significance.2004年11月至2007年12月，研究团队于南极东内陆穹顶C（Dome C）站点采用PM10、PM2.5采样器与多级撞击式采样器，全年不间断采集分粒径气溶胶样品。经化学分析得到的本数据集，构建了南极内陆地区时长最长、时间分辨率最高的海洋飞沫气溶胶（海盐钠离子）观测记录。海洋飞沫气溶胶呈现显著的季节变化特征：南半球冬半年（4月-11月）的观测峰值浓度约为夏半年（12月-3月）的10倍。本研究首次揭示了海洋飞沫气溶胶的粒径分布季节变化规律：冬半年海洋飞沫粒子以亚微米级为主，而夏半年的粒径模态约为1-2 µm。通过天气尺度气象分析，研究明确了将海洋飞沫输送至穹顶C站点的大气环流条件。本研究采用极值分析法结合特定环境判据，提取了将大气环流（均值与距平）与极端海洋飞沫事件相关联的更强示踪特征。针对部分高浓度海洋飞沫事件的气团后向轨迹分析表明，存在两类主要气团输送路径，对应不同的粒径分布特征：来自邻近印太扇区的输送路径对应微米级粒子组分，而途经南极高原的长距离输送路径则对应亚微米级粒子。硫酸根离子（SO₄²⁻）与钠离子的比值的季节变化特征，帮助研究识别出少数相对于海水组分呈现硫酸盐亏损的事件。研究通过甲磺酸（MSA）浓度剖面评估生源性硫酸根的贡献，进而计算得到更为可靠的海盐硫酸盐组分。通过该方法，研究识别出少数可能源自"frost flower"源的事件，这些事件主要集中于4月与9月。与每日采集的表层积雪样品的对比分析表明，气溶胶与积雪中的海洋飞沫气溶胶的变化趋势存在时间偏移。该特征暗示海洋飞沫的沉降过程更为复杂，涉及湿沉降与钻石尘沉降的显著贡献；但未来仍需开展进一步研究，以排除风再分配过程的影响并提升统计显著性。