Convert radiances / irradiances to equivalent output quantity.  

output_quantity quantity

 
where quantity can be one of the following:

brightness

Convert radiances / irradiances to equivalent brightness temperatures.

reflectivity

Calculate transmission / reflectivity instead of absolute quantities. For irradiances / actinic fluxes the transmission T is defined as

T={{E}\over{E_{0}\cos{\theta}}} (1)

where E is the irradiance / actinic flux, E_{0} is the extraterrestrial flux, and \theta is the solar zenith angle. The reflectivity R is defined as

R={{\pi\cdot L}\over{E_{0}\cos{\theta}}} (2)

where L is the radiance, E_{0} is the extraterrestrial flux, and \theta is the solar zenith angle. Obviously, reflectivities do not depend on Sun-Earth distance. Please note the difference to transmittance.

transmission

Calculate transmittance / reflectance instead of absolute quantities. That is, set the extraterrestrial irradiance to 1 and do not correct for Sun-Earth distance:

T=\frac{E}{E_{0}} (3)

where E is the irradiance / actinic flux / radiance and E_{0} is the extraterrestrial flux. Please note the difference to reflectivity.