Parameterizing optical properties of soot-containing aerosols

摘要

In recent years there has been much focus on the impacts of atmospheric aerosol on the radiation field.Nevertheless there is still a large incertitude in quantifying the effects on shortwave and long wave radiation,especially in the case of internally mixed aerosols which is supposed to be the predominant mixing state of atmospheric aerosols.But as well for some externally mixed aerosol types the results are uncertain yet.In addition to this direct aerosol effect a further indirect effect occurs,that is describing the impacts of aerosol burden changes on cloud properties.The sum of both effects may be as important as the much better known effect caused by the greenhouse gases.A great difficulty one has to deal with in determining the aerosol direct impact on the radiation field is the need for Mie calculations,which call for huge amounts of computing power and resulting costs.This laborious process cannot be conducted yet in full coupled runs of atmospheric models,neither on the regional nor on the global scale.As a consequence,the optical properties of aerosols must be parameterized.