Classification of aerosol types using AERONET version 3 data over Kuwait City

Abstract

The particle linear depolarization ratio (PLDR) and single scattering albedo (SSA) at 1020 nm are retrieved by the AERONET (Aerosol Robotic Network) Version 3.0 level 1.5 inversion products are used to categorize different types of aerosols and investigate their temporal distribution for the atmospheric particles of Kuwait City. The results show that when PLDR increases in the atmosphere, the amount of SSA at 440, 670, 870, and 1020 nm wavelength channels and the contribution of coarse-mode particles increased. Also, the spectral behavior of SSA changes from a negative to positive slope by increasing PLDR. The highest density of aerosol incidence rate in the two-dimensional histogram diagram occurs in the range with low fine mode fraction and dust ratio. The main objective of this study is to present that the atmosphere of Kuwait City is strongly affected by pure dust (PD) and polluted dust plumes, namely, dust-dominated mixture (DDM), pollution dominated mixture (PDM), all with an occurrence frequency of 85%. The annual average incidence rate of different aerosol types is 32.2% for DDM, 31% for PD, 21.8% for PDM, 10.3% for SA, 2.5% for MA, 1.3% for WA, and 0.9% for NA, from 2006 to 2019. However, the distribution of different types of pollution particles varies with the seasons change. The incidence rate of pure and polluted dust is more than 85% from March to October. In addition, the annual average incidence rate of dust-free pollution aerosols (NA, WA, MA, and SA) is 15%. The highest amount of dust-free pollution particles in different months is related to the SA that constitutes about 40% in the cold months.