comparisons are made between two radiative codes used to evaluate components of terrestrial radiation budget. The first one, named LlL7 and under development at IAG-USP, produces irradiances from radiances previously computed by LOWTRAN-7 code and integrated along the whole terrestrial spectrum. The second one is included in the INPE/CPTEC general circulation model. Both are tested using realistic and isothermal atmospheres. Sensitivity tests are made for the treatment of water vapor continuum absorption. Conditions established in the ICRCCM program were followed and results of two line-by-line codes were used as a reference for the comparisons. The discrepancies between LlL7 and reference codes seem to depend on columnar water vapor while CPTEC/COLA most times underestimates downward longwave irradiances. Observed systematic errors are due to several reasons such as the different number of spectral intervals used for irradiance integration and different sources of spectroscopic data.Pages: 1477-148
