Synoptic classification of Moderate Resolution Imaging Spectroradiometer aerosols over Israel

Abstract

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.

An overview of regional and local characteristics of aerosols in South Africa using satellite, ground, and modeling data

“…There is a wealth of remotely sensed air quality information available from satellite platforms, and a number of studies have used aerosol optical depth (AOD or τ ) as a proxy for air quality (Zhuang et al, 2014; Luo et al, 2014; Zhang et al, 2014; Qi et al, 2013; Massie et al, 2006; Kumar et al, 2013; Alam et al, 2011; Kaskaoutis et al, 2007; Carmona and Alpert, 2009; Guo et al, 2011; Marey et al, 2011; Sorooshian et al, 2011; Tesfaye et al, 2011; Sreekanth and Kulkarni, 2013; Singh et al, 2004; Crosbie et al, 2014). AOD (aerosol optical depth) typically displays strong seasonality, with higher AOD observed during periods of peak photochemical production of secondary aerosol – except in areas where either dust generation or biomass burning enhances AOD during other seasons.…”

Synoptic conditions favouring the occurrence of aerosol episodes over the broader Mediterranean basin

“…Several authors (e.g. Barkan and Alpert, 2008;Dayan et al, 2008;Carmona and Alpert, 2009;Kalderon-Asael et al, 2009) examined the relation of synoptic-scale circulation patterns in the eastern Mediterranean with changes of mineral aerosol particles between dusty and non-dusty conditions. Recently, other types of aerosol episodes, e.g.…”

Extremely large anthropogenic-aerosol contribution to total aerosol load over the Bay of Bengal during winter season

“…AOD) and aerosol size (e.g.Ångström exponent, effective radius, finemode fraction) is the most common and widely used technique for the discrimination between different aerosol types (e.g. Pace et al, 2006;Kaskaoutis et al, 2007a;El-Metwally et al, 2008;Carmona and Alpert, 2009;Kalapureddy et al, 2009). Thus, scatter plots of AOD vs. α can be obtained in order to discriminate different aerosol types through determination of physically interpretable cluster regions.…”