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.

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 .…”

Modeling study on the transport of summer dust and anthropogenic aerosols over the Tibetan Plateau

“…In adding SPRINTARS to NHM in this study, the advection scheme of Walcek and Aleksic (1998), which guarantees mass conservation, was applied in the transport of aerosols and chemical tracers. Using the advection scheme, Kajino et al (2012) successfully simulated the transport of a chemical tracer. The turbulence scheme of Nakanishi and Niino (2006) and the two-moment bulk cloud microphysical scheme of Yamada (2003) were used.…”

Atmospheric radioactivity over Tsukuba, Japan: a summary of three years of observations after the FDNPP accident

“…The calculated domains cover southern Tohoku and the central part of Honshu. Details of the transport (advection, diffusion, and convective transport) and deposition schemes (dry and wet (in cloud and below cloud, grid-scale and subgrid-scale)) are described in Kajino et al (2012) and Sekiyama et al (2015). We simulated five species of particulate radionuclides (volatile and reactive 131 I (I 2 ), volatile and nonreactive 131 I (CH 3 I), non-volatile 131 I, 134 Cs, and 137 Cs).…”

“…The Eulerian chemical transport model RAQM2 (Kajino et al 2012;Adachi et al 2013;Sekiyama et al 2015) was used to simulate radioactive plume transport from the FDNPP accident over the Kanto Plain. The JMA/MRI non-hydrostatic meteorological model (NHM; Saito et al 2007) was used to simulate the meteorological field to calculate the transport and deposition processes of radionuclides using RAQM2.…”