  In this work we use solar observations with the ALMA radio telescope at the
wavelength of 1.21 mm. The aim of the analysis is to improve understanding of
the solar chromosphere, a dynamic layer in the solar atmosphere between the
photosphere and corona. The study has an observational and a modeling part. In
the observational part full-disc solar images are analyzed. Based on a modified
FAL atmospheric model, radiation models for various observed solar structures
are developed. Finally, the observational and modeling results are compared and
discussed.
