Radiometric in-situ calibration of satelital sensors of Earth   observation using a spectroradiometer
  By using the satelital information of Earth observation unloaded by a station constructed in the country and reflectances measurements of the soil, we found the total radiation attenuation of the atmosphere for a small region of the Colombian territory. It was necessary to use the Fourier's theory that describes the ideal filters of signals to find the transfer functions between the spectral response of an spectroradiometer and the satelital sensor, whose radiative sign we are going to calibrate. After that, we used the reflectance spectrum of the soil taken with our spectroradiometer, the information in digital numbers (DN) of a pixel of the satelital image of the same region at the same time, and using again the theory of ideal filters we found the transfer function between the responses of both sensors to the radiance of the soil. The relation between both signals provides us the total intensity of the radiation attenuation of the atmosphere for pixel, which is fundamental to do a radiometric calibration of the whole image. We found a factor of atmosphere attenuation of the radiation ({\lambda} between 430nm to 830nm) from the soil(of the pixel surface) of H_{Total({\lambda})Atmosphere} = 1,435x 10^{-3}. 
Camilo Delgado-Correal, Jos\'e E. Garc\'ia
physics.ao-ph astro-ph.IM