Aerosols over the Arabian Sea

This paper provides an overview of dust transport pathways and concentrations over the Arabian Sea during 1995. Results indicate that the transport and input of dust to the region is complex, being affected by both temporally and spatially important processes. Highest values of dust were found off the Omani coast and in the entrance to the Gulf of Oman. Dust levels were generally lower in summer than the other seasons, although still relatively high compared to other oceanic regions. The Findlater jet, rather than acting as a source of dust from Africa, appears to block the direct transport of dust to the open Arabian Sea from desert dust source regions in the Middle East and Iran/Pakistan. Dust transport aloft, above the jet, rather than at the surface, may be more important during summer. In an opposite pattern to dust, sea salt levels were exceedingly high during the summer monsoon, presumably due to the sustained strong surface winds. The high sea salt aerosols during the summer months may be impacting on the strong aerosol reflectance and absorbance signals over the Arabian Sea that are detected by satellite each year.本文概述了1995年阿拉伯海海域的沙尘传输路径与沙尘浓度特征。研究结果显示，该区域的沙尘传输与沉降过程极为复杂，同时受时空尺度上的关键物理过程调控。沙尘浓度峰值出现在阿曼沿岸以及阿曼湾入口区域。夏季沙尘浓度整体低于其他季节，但相较于其他大洋区域仍处于较高水平。芬德勒特急流（Findlater jet）并未成为非洲沙尘的输送源，反而似乎阻碍了中东、伊朗/巴基斯坦沙漠沙尘源区向开阔阿拉伯海的直接沙尘传输。夏季时段，急流层上方高空的沙尘传输而非地表沙尘传输，可能占据主导地位。与沙尘浓度变化趋势相反，夏季季风期间海盐气溶胶浓度极高，推测这与持续强劲的地表风场有关。夏季的高浓度海盐气溶胶，可能对每年卫星探测到的阿拉伯海海域强烈的气溶胶反射与吸收信号产生影响。