Development and application of a new air pollution modeling system — Part III. Aerosol-phase simulations

摘要: Abstract A new air pollution modeling system is discussed and applied. The consists of GATOR, a gas, aerosol, transport, radiation quality model MMTD, mesoscale meteorological tracer dispersion model. gas-phase processes treated by GATOR include photochemistry, deposition, emissions, gas-to-particle conversion. To solve stiff chemical rate equations, sparse-matrix, vectorized Gear-type code (SMVGEAR) was used. aerosol in coagulation, aqueous chemistry, equilibrium, condensational growth, dissolutional evaporation, nucleation, sedimentation. transport horizontal advection diffusion vertical convection diffusion. Finally, the algorithm calculates ultraviolet, visible, infrared optical depths, mean intensities for photodissociation rates, radiative heat fluxes temperature calculations. MMTD predicts winds, diffusion, temperature, pressure, humidity, soil moisture, rainfall. These variables are fed to heating rates from back MMTD. With GATOR/MMTD system, simulated Southern California Air Quality Study (SCAQ) days 26–28 August 1987. Results were compared surface measurements many parameters. predicted normalized gross errors ozone 17.6% 23.4% at 2:30 p.m. on first second simulation, respectively. Also, error during 12 h simulation 22%. Correct emissions initial mixing ratios appear be necessary obtaining good results. Initial conditions outside basin seem affect results third days. Time-series plots, statistics, sensitivity test discussed. Aerosol will shown later work.