Publications

Masoumi, A; Laleh, E; Bayat, A (2019). Optical and physical properties, time-period, and severity of dust activities as a function of source for the main dust sources of the Middle East. JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS, 185, 68-79.

Abstract
To achieve long-time and comparable aerosol properties with the maximum geographical coverage possible in the Middle East, four AERONET sites (Kuwait university, Solar village, IASBS, and Mezaira) are selected. Aerosol optical depth (AOD) at 870 nm, Angstrom exponent (alpha) for two wavelengths, 440 and 870 nm, real and imaginary parts of aerosol refractive index at 870 nm (m(r), m(i)), and aerosol effective radius are studied for these sites during 2010-2017. Daily-mean values of aerosol properties (m(r) >= 1.51, m(i) <= 0.013, and alpha <= 0.88), show that dust particles are the dominant aerosol type in the atmosphere of the Middle East area. It has been seen that dusty days (daily-mean AOD(870) >= 0.50, and alpha <= 0.50), assign a notable percentage (14%-19%) of all days of data for all sites with the exception of the IASBS site. Based on the monthly-averaged MODIS-Terra Deep Blue AOD at 550 nm, it is seen four main dust sources in the Middle East: Mesopotamian area in Iraq and East Syria, northern part of the Arabian Peninsula, Elrob Elkhali desert at southern part of the Arabian Peninsula, and sources of East Arabian Peninsula located in Oman country. All sources of dust are active during dry months in spring and summer seasons. The monthly-averaged wind field data of ERA-interim ECMWF model reveals that dust events in northern part of the Arabian Peninsula are mainly originated from North Arabian Peninsula (Tigris-Euphrates basin) sources in spring (summer). In East Arabian Peninsula (Mezaira site), dusty conditions have continued until late summer and it is related to dust activities of sources, located at southern (Elrob Elkhali desert) and eastern part (Oman country) of the Arabian Peninsula. Dust recorded in Iran plateau (IASBS site), can be originated from sources of Tigris-Euphrates basin via westerly wind at higher altitudes. Also, it seems that dust particles originated from Tigris-Euphrates basin, have smaller sizes and higher values of complex refractive index and therefore it is essential to consider source functionality of dust particles optical and physical properties for each sub-region of the Middle East.

DOI:
10.1016/j.jastp.2019.01.015

ISSN:
1364-6826