1.8 CF Standard Names: Optical Thickness of Atmosphere Layer due to Ambient Aerosol Particles (optical_thickness_of_atmosphere_layer_due_to_ambient_aerosol_particles)

Record Label : optical_thickness_of_atmosphere_layer_due_to_ambient_aerosol_particles

Record Title : Optical Thickness of Atmosphere Layer due to Ambient Aerosol Particles

CF Standard Name : optical_thickness_of_atmosphere_layer_due_to_ambient_aerosol_particles

Record Description : The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-optical_thickness) on traversing the path. A coordinate variable of radiation_wavelength or radiation_frequency can be specified to indicate that the optical thickness applies at specific wavelengths or frequencies. "Layer" means any layer with upper and lower boundaries that have constant values in some vertical coordinate. There must be a vertical coordinate variable indicating the extent of the layer(s). If the layers are model layers, the vertical coordinate can be model_level_number, but it is recommended to specify a physical coordinate (in a scalar or auxiliary coordinate variable) as well. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase.

Canonical Units : 1