A case study of dust aerosol radiative properties over Lanzhou, China

Abstract

Abstract. The vertical distribution of dust aerosol and its radiative properties are analysed using the data measured by the micropulse lidar, profiling microwave radiometer, sunphotometer, particulate monitor, and nephelometer at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) during a dust storm from 27 March to 29 March 2007. The analysis shows that the dust aerosol mainly exists below 2 km in height, and the dust aerosol extinction coefficient decreases with height. The temporal evolution of aerosol optical depth (AOD) during the dust storm is characterized by a sub-maximum at 22:00 (Beijing Time), 27 March and a maximum at 12:00, 28 March. The AOD respectively derived by lidar and sunphotometer shows a good consistency. The PM 10 concentration and aerosol scattering coefficient share similar variation trends, and their maximums both appear at 22:00, 27 March.The aerosol extinction coefficient and relative humidity have the similar trends and their maximums almost appear at the same heights, which presents a correlation between extinction coefficient and relative humidity known as aerosol hygroscopicity. The relative humidity is related with temperature, and then the temperature will affect the aerosol extinction properties by modifying the relative humidity condition.The aerosol extinction coefficient, scattering coefficient, and PM 10 concentration present good linear correlations. The correlation coefficients of the aerosol scattering coefficients of 450, 520, and 700 nm and PM 10 concentration, of aerosol extinction coefficient retrieved by lidar at 532 nm and PM 10 concentration, and of aerosol extinction and scattering coefficient are respectively 0.98, 0.94, and 0.96.

Seasonal variation of surface and vertical profile of aerosol properties over a tropical urban station Hyderabad, India

“…Anderson et al [2003] calculated LR values of 50 AE 5 sr for fine-mode dominated samples and 46 AE 8 sr for coarse-mode dominated samples at low RH during the ACE-Asia. Literature survey of various LR values estimated at different environments over the globe is presented in He et al [2006] and Zhang et al [2010], which are close to our findings in the vast majority of the cases.…”

“…The BSC profile (Figure 9a) also reveals the structure of thin elevated aerosol layers that are comparable in magnitude with the boundary layer. Accurately assessing the origin of such layers is highly uncertain, since they are somewhat different than those observed during major dust storms [Liu et al, 2008b;Chen et al, 2010;Zhang et al, 2010]. Several previous studies over Southeast Asia Müller et al, 2003;Ganguly et al, 2006;Niranjan et al, 2006Niranjan et al, , 2007Satheesh et al, 2006Satheesh et al, , 2009Rajeev et al, 2010;Mishra et al, 2010;Komppula et al, 2012] show that the aerosol plumes can rise up to 3-5 km, while some of the studies [e.g.…”

Urban particle size distributions during two contrasting dust events originating from Taklimakan and Gobi Deserts

“…The study of Huang et al (2010a) indicated the transport pathways of dust, concentrations of pollutant precursors and meteorological conditions were main factors affecting the mixing extent of pollutants with dust. Mostly previous studies about mixing of Asian dust with urban pollution focused on Beijing in northern China Sun et al, 2005;Wang et al, 2005aWang et al, , 2005bZhang et al, 2010aZhang et al, , 2010bZhao et al, 2007). However, Unlike Beijing with more polluted cities in its southern and southwestern directions such as Shijiazhuang and Tianjin, air mass at Lanzhou were mostly from northern or northwestern direction with much less pollution.…”

“…Located in the transport pathway of Asian dust storms, Lanzhou is usually impacted by dust storms. Several studies about dust aerosol particles have been conducted in Lanzhou (Feng et al, 2011;Huang et al, 2008;Liu et al, 2004Liu et al, , 2012Qu et al, 2010;Ta et al, 2004;Tao et al, 2007;Wang et al, 2006Wang et al, , 2009Zhang et al, 2010aZhang et al, , 2010bZhang and Li, 2012). Chu et al (2008) showed that the concentration of the total suspended particles (TSP) in Lanzhou was 2e10 times higher than the third-level air quality criterion (severe pollution) during winter and spring, partly due to dust events.…”

An overview of passive and active dust detection methods using satellite measurements

“…Dust aerosols directly affect the earth's atmospheric radiation balance by absorbing and scattering solar radiation, and by absorbing and re-emitting outgoing longwave radiation (Tegen, 2003;Fu et al, 2009;Zhang et al, 2010;Hansell et al, 2012;Zhao et al, 2013). They can also indirectly affect the climatic system by acting as cloud condensation nuclei and altering the microphysical properties, albedo, and lifetime of clouds (Albrecht, 1989;Yin et al, 2002;Huang et al, 2006a, b;Su et al, 2008;Wang W. C. et al, 2010).…”