Synoptic classification of Moderate Resolution Imaging Spectroradiometer aerosols over Israel

The origins and variety of aerosols in Israel are strongly influenced by synoptic conditions as well as other variables. Days affected by a weak Persian trough system are characterized by coarse aerosols from North Africa, which contain mainly mineral dust aerosols, whereas days affected by the Red Sea trough with an eastern axis are characterized by fine aerosols from northern Europe. Some synoptic systems contain both groups of aerosols as well as mixed aerosols, e.g., the Red Sea trough with a central axis. This study utilizes the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra Satellite to obtain a synoptic classification of aerosols over Israel for 6 years. MODIS synoptic classification revealed a number of different aerosol types. For weak Persian trough, a high from the west and a medium Persian trough, the MODIS Terra aerosol optical thickness (AOT) fine mode fractions are 0.51, 0.54, and 0.51, respectively. While for Red Sea trough with an eastern or central axis AOT fine mode fraction (‘f’) is higher and is equal to 0.63 and 0.59, respectively. This is the first study in the region that investigates average back trajectory with regards to both synoptic systems and aerosol type. Investigation of back trajectories for the Persian trough synoptic system indicates that days with low ‘f’ at 700 hPa are associated with flows from North Africa, while days with high ‘f’ are linked to flow from Europe. Most of our findings are not unexpected, but provide the first 6 years quantified aerosol classification which is based on the synoptic systems.