Aerosol attenuation model for Scandinavian environment; User manual

The aerosol extinction model NORAM for Scandinavian environment has been implemented in a user friendly form. This user manual describes installation and usage of the model and computer program NORAM (Nordic Aerosol Model). FOI has earlier carried out transmission measurements with a multi channel transmissometer (OLA) in order to characterize the aerosol attenuation in IR for Swedish conditions. The reason was that IR transmission models (mostly American) underestimated the IR attenuation compared to measurements. Data from the OLA measurements have been analyzed and have resulted in a number of models of how the aerosol attenuation depends on the weather. The models have earlier not been suited to distribute outside FOI. In cooperation between FOI and PvTT in Finland (The Finnish Defence Forces Technical Research Centre) the study has been resumed and has resulted in models for how the aerosol attenuation depends on the most common meteorological parameters. The models have been implemented in a computer program (NORAM) which lets the user define input data to a suitable model and calculates the aerosol attenuation. The input data are also used in MODTRAN calculation of the gas attenuation. The user can study the calculated results in graphic and numeric form.