Wednesday, 25 January 2012: 2:15 PM
Modeling Air and Precipitation Quality in Japan Using a Chemical Meteorology Model (NHM-Chem)
Room 244 (New Orleans Convention Center )
A new online coupled meteorology-chemistry model (NHM-Chem) was developed to simulate trace gas and aerosol chemistry, aerosol dynamics and cloud microphysics. The category approach of Eulerian, Multiscale, Tropospheric Aerosol Chemistry and dynamics Simulator (EMTACS) was utilized to simulate aerosol and cloud microphysical processes. In the approach, aerosols are classified into 4 categories, NUC (nucleation category), ACM (accumulation mode), AGR (soot aggregate), COR (coarse mode) and clouds are classified into 5 categories CLD (cloud), ICE (cloud ice), RNW (rain), SNW (snow) and GRW (graupel). Size distribution of each category is characterized by single mode prescribed functions, the log-normal functions for aerosols and the gamma function for clouds. A three moment bulk model, Modal Aerosol Dynamics model for multiple Modes and fractal Shapes (MADMS) was used to calculate aerosol dynamical processes, whereas a two moment bulk model was used for simulating mixed-phase cloud microphysical processes. Therefore, number concentrations of air-borne particles (aerosols and hydrometeors) from 1nm to several cm are consistently preserved in the model framework. To resolve the rapid growth in aerosol size from nucleation mode (several nm) to accumulation mode (several hundred nm), NUC category is discretized into 4 modal bins. Modal Bin Hybrid Model (MBHM) is used to simulate the aerosol dynamics for the 4 discretized modes. The NHM-Chem model can predict non-equilibrium and competitive processes of aerosol nucleation, condensation and coagulation growth from 1nm to super-micro meters of aerosol particles. As the lateral and upper boundary concentrations, NOx, Ox, CO and VOCs are used, simulated by a global-scale stratospheric and tropospheric chemical climate model (MRI-CCM2) on hourly basis. Thus, the present regional model is so-called a 1 way nested model of the global chemical climate model. A regional-scale simulation was performed for the entire year of 2006, covering Northeast Asian region. We present the model performance regarding major inorganic components in the air and rain/snow precipitation in Japan; hourly air concentrations of SO2, NO, NO2, NOx, O3, PM2.5, PM10, PM1-nss-SO42-, PM1-NH4+, daily, weekly or 2-weekly air concentrations of aerosol nss-SO42-, NO3-, Cl-, NH4+, Na+, Ca2+, and daily or weekly concentration of nss-SO42-, NO3-, NH4+, Na+, Ca2+, H2O in rain and snow precipitation.