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.

本论文概述了1995年阿拉伯海海域的粉尘输送路径与浓度分布特征。研究结果显示，该区域的粉尘输送与输入过程极为复杂，同时受时空尺度显著的关键大气过程影响。阿拉伯海靠近阿曼沿岸以及阿曼湾入口区域的粉尘浓度最高。尽管与其他大洋区域相比仍处于较高水平，但夏季的粉尘浓度整体低于其他季节。芬德勒急流(Findlater jet)并未作为非洲的粉尘源区，反而似乎阻断了中东以及伊朗/巴基斯坦的沙漠粉尘源区向开阔阿拉伯海的直接粉尘输送过程。夏季期间，急流上方高空的粉尘输送而非地表粉尘输送，可能发挥更为关键的作用。与粉尘浓度变化趋势截然相反，夏季季风期间的海盐浓度极高，推测这是由持续强劲的地表风力所致。夏季的高浓度海盐气溶胶，可能会对每年通过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。