We present MATRIX-VBS, a new aerosol scheme that simulates organic partitioning in an aerosol microphysics model, as part of the NASA GISS ModelE Earth System Model. MATRIX-VBS builds on its predecessor aerosol microphysics model MATRIX and was developed in the box model framework. The scheme features the inclusion of organic partitioning between the gas and particle phases and the photochemical aging process using the volatility-basis set. To assess the performance of the new model, we compared its mass concentration, number concentration, and activated number concentration to the original scheme MATRIX, and evaluated its mass concentrations in four seasons against data from the NASA Atmospheric Tomography Mission (ATom) aircraft campaign. Results from MATRIX-VBS show that organics are transported further away from their source, and their mass concentration increases aloft and decreases at the surface as compared to those in MATRIX. The mass concentration of organics at the surface agrees well with measurements, and there are discrepancies for vertical profiles aloft. In the new scheme, the global mass load of organic aerosols increased by 40.0%, there is also an increased number of particles at the surface by 23.4% and fewer activated ones in most regions. The new scheme presents advanced and more comprehensive capability in simulating aerosol processes.
 

organic aerosol volatility