Improvements in the Advanced Navy Aerosol Model (ANAM)

摘要

The Navy Aerosol Model (NAM) is widely used as an engineering tool to provide a quick estimate of the aerosol extinction in the marine environment. Since its introduction, several shortcomings of NAM have been identified that are being addressed by the development of the Advanced Navy Aerosol Model (ANAM). At present, the Advanced Navy Aerosol Model has been reviewed as concerns its production mode. The two separate production modes (3rd and 4th modes in ANAM4) have been replaced by a single production mode in ANAM5. The shape of the new production mode is given by two sea spray source functions taken from literature, Vignati et al. and Smith and Harrison. The intensity of the new production mode in ANAM5 at a particular height above the surface is governed by a transfer function that depends on radius and wind speed. The production mode in ANAM5 has several tuning parameters that have been optimized by comparing ANAM5 concentration predictions to experimental aerosol data. ANAM5 performs better than ANAM4 in predicting the concentrations of large aerosols in open ocean conditions, but the performance is reduced in the coastal zone. This may be due to the presence of a strong advection mode that is currently not well taken into account by the ANAM.