Model simulation and analysis of coarse and fine particle distributions during ACE‐Asia

Abstract

[1] The Taiwan air quality model incorporating a dust module was applied to calculate masses of supermicron (diameter greater than 1 mm) and submicron particles (diameter less than 1 mm) and their dust fractions during the ACE-Asia airborne experiments over the northwestern Pacific. The results showed that the calculated vertical profiles of supermicron particle concentrations matched reasonably well with the observations obtained from 19 research aircraft missions. During dust storm events and at dust concentrated altitudes, the calculated dust fractions in the supermicron particles were usually greater than 90%, and the dust was concentrated in the lower troposphere mainly below 6 km. Without dust storm, dust was still the major component of the supermicron particles above boundary layer. In contrast to supermicron particles, the model results showed that the major component of the submicron particles observed during aircraft experiments was mostly from pollution. The calculated vertical profiles of submicron particle concentrations were sensitive to the emission inventory of air pollutants over east Asia. The correlation between observed anthropogenic volatile organic compound and submicron particles were used to identify the pollution fraction in the submicron particles, and the results were consistent with the model calculations of dust fraction. The model results showed that the dust fractions in the submicron particles were usually less than 28% in the boundary layer. During dust storm events the dust fractions were usually greater than 40% but can be as low as 24% when significant amount of pollutants were present.

Drought-sensitivity of fine dust in the US Southwest: Implications for air quality and public health under future climate change

“…We rely on ground-based measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network to calculate surface fine dust concentrations in the southwestern US (defined here as 31 • -41 • N, 115 • -103 • W; spanning Arizona, Colorado, New Mexico, and Utah) [49]. We use the iron content of PM 2.5 as a fine dust proxy, following the approach first proposed by Hand et al [7] and subsequently updated by Achakulwisut et al [9], to calculate monthly mean fine dust concentrations.…”

Characterizing the transport pathways of Asian dust

“…During these periods, concentrations of aerosol particles greater than 100 μg m −3 were obtained by the corresponding eight flight cases on board the NCAR C‐130 research aircraft. Results of Tsai et al 's [2004] model calculations indicated that these high concentrations of aerosol particles usually consisted of more than 90% dust. Therefore the aircraft measurements from these 8 flight cases are selected in this study for dust transport analyses.…”

“…The dust module in the Taiwan Air Quality Model (TAQM‐Dust) [ Tsai et al , 2004] is developed to simulate regional dust distributions over Asia. The three‐dimensional TAQM is a regional model used to simulate the time‐varying three‐dimensional distribution of trace gases and particles [ Jeng et al , 2000].…”

Towards the improvements of simulating the chemical and optical properties of Chinese aerosols using an online coupled model – CUACE/Aero

“…A number of models have been developed and used to simulate the PM other than mineral dust aerosol in East Asia in several projects, e.g. TRACER-P, ACE-Asia and MICS-ASIA projects (Chin et al, 2003;Gong et al, 2003b;Zhang et al, 2003;Tang et al, 2004;Tsai et al, 2004;Carmichael et al, 2008) and the Cloud Indirect Forcing Experiment (CIFEX) (Wilcox et al, 2006) and the East Asian regional Experiment (EAREX) (Nakajima et al, 2007). However, due to different purposes, those works were mostly focused on aerosols in the outflow of Asian continent or in Asian mega cities.…”