| 초록 |
With the aim to estimate the global distribution of black carbon aerosols, size dependent atmospheric aerosol processes were parameterized in MOCAGE, a Chemistry and Transport Model. Particle size distribution was represented by mono mode log-normal distribution and discretized by particle size in 30 groups that were treated as independent tracer in the model. Wet deposition processes were parameterized in two different ways, in- and below-cloud scavenging, depending on the phase of precipitation. In-cloud scavenging distinguishes the chemical composition of the aerosols but not the particle size whereas below-cloud scavenging differentiates the particle size but not the chemical composition. We also took into account the problem of precipitation that covers only a fraction of the grid for two ways of scavenging. Comparison of the simulated results with observations made during the IOP of ESCOMPTE program in June 2001 in southern part of France showed the results are in general in accordance with the observations with an uncertainty of within a factor 10, typical order of magnitude for the state-of-the-art of global modeling. The global distribution of aerosol concentration was very inhomogeneous in the troposphere with a contrast over continent to over ocean while it was relatively homogeneous in the high altitude. Wet scavenging was appeared to be most active in 1.5-5 km altitude due to the superposition of the two scavenging processes in this altitude. The estimated mean atmospheric residence time of black carbon aerosols was found to be about one week, in good agreement with that in the literature. |
