Development of the RAQM2 aerosol chemical transport model and predictions of the Northeast Asian aerosol mass, size, chemistry, and mixing type

Abstract

Abstract.A new aerosol chemical transport model, the Regional Air Quality Model 2 (RAQM2), was developed to simulate the Asian air quality. We implemented a simple version of a triple-moment modal aerosol dynamics model (MADMS) and achieved a completely dynamic (nonequilibrium) solution of a gas-to-particle mass transfer over a wide range of aerosol diameters from 1 nm to super-µm. To consider a variety of atmospheric aerosol properties, a category approach was utilized in which the aerosols were distributed into four categories: particles in the Aitken mode (ATK), soot-free particles in the accumulation mode (ACM), soot aggregates (AGR), and particles in the coarse mode (COR). The aerosol size distribution in each category is characterized by a single mode. The condensation, evaporation, and Brownian coagulations for each mode were solved dynamically. A regional-scale simulation ( x = 60 km) was performed for the entire year of 2006 covering the Northeast Asian region. The modeled PM 1 /bulk ratios of the chemical components were consistent with observations, indicating that the simulated aerosol mixing types were consistent with those in nature. The non-sea-salt SO 2− 4 mixed with ATK + ACM was the largest at Hedo in summer, whereas the SO 2− 4 was substantially mixed with AGR in the cold seasons.Ninety-eight percent of the modeled NO − 3 was mixed with sea salt at Hedo, whereas 53.7 % of the NO − 3 was mixed with sea salt at Gosan, which is located upwind toward the Asian continent. The condensation of HNO 3 onto sea salt particles during transport over the ocean accounts for the difference in the NO − 3 mixing type at the two sites. Because the aerosol mixing type alters the optical properties and cloud condensation nuclei activity, its accurate prediction and evaluation are indispensable for aerosol-cloud-radiation interaction studies.

Evaluation of the Community Multiscale Air Quality (CMAQ) model v5.0 against size-resolved measurements of inorganic particle composition across sites in North America

“…5. Consistent with previous results of Kelly et al (2010), the model frequently underestimates the moderate (25-50 %) levels of chloride depletion seen at the BRACE sites (AZP, GAN, and SYD), which are within 20 km or less from Tampa Bay. The negative bias in the amount of chloride depletion is slightly greater at BRG (not shown).…”

Evaluation of the Community Multiscale Air Quality (CMAQ) model v5.0 against size-resolved measurements of inorganic particle composition across sites in North America

“…5. Consistent with previous results of Kelly et al (2010), the model frequently underestimates the moderate (25-50 %) levels of chloride depletion seen at the BRACE sites (AZP, GAN, and SYD), which are within 20 km or less from Tampa Bay. The negative bias in the amount of chloride depletion is slightly greater at BRG (not shown).…”

The MESSy aerosol submodel MADE3 (v2.0b): description and a box model test

“…Van Dingenen and Raes, 1991;Kerminen and Wexler, 1995;Jefferson et al, 1997;Bardouki et al, 2003) and used in models (0.1-1; e.g. Vignati et al, 2004;Zaveri et al, 2008;Mann et al, 2010;Kajino et al, 2012). Here, we use α H 2 SO 4 = 1 as in former generations of the submodel, which was also found to be in agreement with field measurements by .…”

Sensitivity of black carbon concentrations and climate impact to aging and scavenging in OsloCTM2–M7

“…Our overall findings are in line with other recent studies. The tendency to overestimate high-altitude BC concentrations over the Pacific has been noted for several other model (Kipling et al, 2013;Samset et al, 2014;Schwarz et al, 2013;Wang et al, 2014). The vertical profiles from OsloCTM2-M7 also fall roughly within the range of the Ae-roCom Phase II models (Samset et al, 2014).…”

Evaluation of the Community Multiscale Air Quality (CMAQ) model v5.0 against size-resolved measurements of inorganic particle composition across sites in North America

“…5. Consistent with previous results of Kelly et al (2010), the model frequently underestimates the moderate (25-50 %) levels of chloride depletion seen at the BRACE sites (AZP, GAN, and SYD), which are within 20 km or less from Tampa Bay. The negative bias in the amount of chloride depletion is slightly greater at BRG (not shown).…”

The MESSy aerosol submodel MADE3 (v2.0b): description and a box model test

“…Van Dingenen and Raes, 1991;Kerminen and Wexler, 1995;Jefferson et al, 1997;Bardouki et al, 2003) and used in models (0.1-1; e.g. Vignati et al, 2004;Zaveri et al, 2008;Mann et al, 2010;Kajino et al, 2012). Here, we use α H 2 SO 4 = 1 as in former generations of the submodel, which was also found to be in agreement with field measurements by .…”

Sensitivity of black carbon concentrations and climate impact to aging and scavenging in OsloCTM2–M7

“…Our overall findings are in line with other recent studies. The tendency to overestimate high-altitude BC concentrations over the Pacific has been noted for several other model (Kipling et al, 2013;Samset et al, 2014;Schwarz et al, 2013;Wang et al, 2014). The vertical profiles from OsloCTM2-M7 also fall roughly within the range of the Ae-roCom Phase II models (Samset et al, 2014).…”

Evaluation of the Community Multiscale Air Quality (CMAQ) model v5.0 against size-resolved measurements of inorganic particle composition across sites in North America

“…5. Consistent with previous results of Kelly et al (2010), the model frequently underestimates the moderate (25-50 %) levels of chloride depletion seen at the BRACE sites (AZP, GAN, and SYD), which are within 20 km or less from Tampa Bay. The negative bias in the amount of chloride depletion is slightly greater at BRG (not shown).…”

The MESSy aerosol submodel MADE3 (v2.0b): description and a box model test

“…Van Dingenen and Raes, 1991;Kerminen and Wexler, 1995;Jefferson et al, 1997;Bardouki et al, 2003) and used in models (0.1-1; e.g. Vignati et al, 2004;Zaveri et al, 2008;Mann et al, 2010;Kajino et al, 2012). Here, we use α H 2 SO 4 = 1 as in former generations of the submodel, which was also found to be in agreement with field measurements by .…”

Sensitivity of black carbon concentrations and climate impact to aging and scavenging in OsloCTM2–M7

“…Our overall findings are in line with other recent studies. The tendency to overestimate high-altitude BC concentrations over the Pacific has been noted for several other model (Kipling et al, 2013;Samset et al, 2014;Schwarz et al, 2013;Wang et al, 2014). The vertical profiles from OsloCTM2-M7 also fall roughly within the range of the Ae-roCom Phase II models (Samset et al, 2014).…”