In this study, the combination of multiple satellite data was used to improve the assessments of aerosol properties including the aerosol optical depth, Angstrom exponent, UV aerosol index, and single scattering albedo over a semi-arid urban area during the period from 2008 to 2017. The data sets were derived from MODIS and OMI. The critical threshold values for each of the aerosol properties have been defined according to the previous studies to determine different aerosol types.

Results of long term analysis of aerosol properties show that all parameters present a distinct monthly variation. A slightly increasing trend is detected for aerosol index values and this indicates the presence of more absorbing aerosols in recent years. There also is an obvious, consistent cooling effect of aerosols based on the variation of single scattering albedo. The aerosol optical depth relative frequency histogram shows a wide range of values with a maximum of about 40% around the range of 0.3 which is generally higher than some other polluted cities in the world. However, the Angstrom exponent peak around 0.8 likely means the dominance of aerosols in coarse mode.

The results of the determination of different aerosol type show that, right after the mixed type aerosols, the urban/industrial aerosol type is the second-highest contributor to the aerosol composition and that it is followed by dust aerosols. On the other hand, maritime aerosols and smoke, present in less than 5% of the days studied, do not have a significant contribution. Seasonal analysis of different aerosol types indicates the dominance of large absorbing aerosols, i.e. dust during summertime, and small aerosols with non-absorbing properties, i.e. urban/industrial aerosols, mostly during cold seasons.

在这项研究中，使用了多个卫星数据的组合来改善对气溶胶性质的评估，包括在2008年至2017年期间半干旱市区的气溶胶光学深度，埃指数，紫外线气溶胶指数和单散射反照率数据集来自MODIS和OMI。根据先前的研究确定了每种气溶胶特性的临界阈值，以确定不同的气溶胶类型。

气溶胶特性的长期分析结果表明，所有参数都呈现出明显的每月变化。检测到气溶胶指数值略有增加的趋势，这表明近年来存在着更多吸收性气溶胶。基于单个散射反照率的变化，气溶胶还具有明显，一致的降温效果。气溶胶光学深度相对频率直方图显示的值范围很广，在0.3的范围内最大值约为40％，通常高于世界上其他受污染的城市。但是，埃斯特罗姆（Angstrom）指数峰值在0.8附近可能意味着在粗模式下气溶胶占主导地位。

不同气溶胶类型的测定结果表明，紧随混合气溶胶之后，城市/工业气溶胶类型是气溶胶成分的第二大贡献者，其次是粉尘气溶胶。另一方面，在少于5％的研究天数中存在的海洋气溶胶和烟雾没有显着贡献。对不同类型气溶胶的季节性分析表明，吸收性较大的气溶胶（即夏季的灰尘）占主导地位，而具有非吸收性的小型气溶胶（即城市/工业气溶胶）则主要在寒冷季节占主导地位。