Impact of pollution on the optical properties of trans‐Pacific East Asian dust from satellite and ground‐based measurements

Abstract

We investigate changes in the optical properties of a large dust plume originating from East Asian deserts during its transport over the northwestern Pacific Ocean in March 2013. The study makes use of observational products from two sensors in the NASA A-Train satellite constellation, the Moderate Resolution Imaging Spectroradiometer and the Cloud-Aerosol Lidar with Orthogonal Polarization. Forward trajectory clustering analysis and satellite observations show that dust initiating from the Taklimakan and Gobi deserts experienced thorough mixing with industrial pollution aerosols shortly after leaving the source region and were lofted by a strong midlatitude weather system to more than 4 km in height. The dust plume accompanied the weather system and reached the east coast of the North American continent within 7-10 days. The dust aerosols became spectrally absorptive during transport due to mixing with other aerosol types such as soot. Furthermore, a decrease in the depolarization ratio suggests that the complexities in aerosol particle morphologies were reduced during transport over the ocean. More than half of the dust aerosol layers surviving the trans-Pacific transport were polluted and exhibited different optical properties and radiative effects from those of pure dust.

The relationship between anthropogenic dust and population over global semi-arid regions

“…Therefore, studies on different types of aerosols are necessary in the study of radiative effect (J. Huang et al, 2009Wang et al, 2010;Yi et al, 2014).…”

Characterizing a persistent Asian dust transport event: Optical properties and impact on air quality through the ground-based and satellite measurements over Nanjing, China

“…However with long-range transport, Asian dusts often mix with anthropogenic pollutants such as black carbon and sulfate, thus exhibiting relatively complex optical properties and radiative effects (Huang et al, 2010a,b;Yi et al, 2014). Meanwhile, atmospheric chemical transport models are increasingly being used to quantify Asian-dust transport and contributions to atmospheric particulate matter (PM) concentration (Uno et al, 2006).…”

Effect of particle shape on dust shortwave direct radiative forcing calculations based on MODIS observations for a case study

“…The uncertainty in estimating direct radiative forcing is partially due to the inherent difficulties in accurately determining the geometric size, morphology and mineralogical composition of dust particles, as well as their associated single scattering properties (Sokolik et al, 2001;Reid et al, 2003). Moreover, the direct radiative forcing of dust aerosols also depends on external conditions such as the solar zenith angle, underlying surface reflectance, and mixing processes during their transport (Lin et al, 2013;Yi et al, 2014a).…”