Analysis of the change in mineral dust optical over the Eastern Mediterranean with source location using SEAWIFS imagery

摘要

Mineral dust from surrounding arid regions is the major aerosol in the Mediterranean atmosphere during spring and summer. The Eastern Mediterranean is particularly interesting because mineral dust may come from three different sources, originate from the central Sahara in spring, the eastern Sahara in summer and the Middle East/Arabian peninsula in autumn. We obtain the best agreement between SeaWiFS and Sun-Photometer derived aerosol optical thickness by considering the optical properties dust transported from different sources. Dust optical properties over the Eastern Mediterranean can be separated in two categories with different absorption efficiencies. By using the TOMS absorbing aerosol product to locate the dust sources, we found that mineral dust that comes from Middle East Arabian Peninsula has lower absorption in blue and green parts of the solar spectrum than dust coming from Sahara. In addition, we found that the dust coming from Sahara over the Eastern Mediterranean has optical properties similar to that transported over the Atlantic. This new set of mineral dust optical properties will be used to improve ocean color estimates in the Eastern Mediterranean Sea.