Nanodata technology of aerosol index over Iraq during 2005-2020

Abstract

The Aerosol Index (AI) is a measure of the number of UV-absorbing aerosols in the air, such as soot and desert dust. The AI is positive for absorbing aerosols and negative for non-absorbing aerosols. AI is derived from the Ozone Monitoring Instrument (OMI) on board the Dutch–Finnish Aura satellite. In this work AI is analyzed over Iraq for the period 2005 to 2020. The results show significant spatial and temporal variabilities of the seasonal AI with lower (<1) at the southern parts and higher (>2) at the southern part. The AI is significantly changes from season to season being low during winter and high during summer. AI in spring is higher than that in autumn, especially in the south, due to more frequent northwesterly wind. The effect of rain shortage and the large NW Shamal wind on AI are apparent since AI is very high along the alluvial plain during summer The box, whisker plots of mon AI for six cities, chosen to consist of different regions of Iraq, show that Mosul records the lowest minimum AI (~0.1) and the lowest average (~1.1). Anah exhibits the highest maximum AI (~4.1), while Basra has the highest mean value (~2.0). Outliers in AI are observed only in Rutba (two cases) and Al-Nukhaib (one case). Mann-Kendall test on the seasonal AI of the six cities indicates a significant decreasing trend of AI is observed during summer season in all cities and the trend is most significant in Mosul, Anah, Baghdad, and Basra. The most decreasing trend during Autumn occurred in the city of Basra. AI contours overlaid on MODIS false colors images in three different dust storms cases and one non-dust case revels that AI can provide information on the severity, gradient, location of core, and tracking path of a dust storm.