The canopy and atmosphere radiative transfer models SLC and MODTRAN were coupled to simulate top-of-atmosphere (TOA) radiance data for 3 Norway spruce stands in Eastern Czech Republic. The simulations fitted the near-nadir CHRIS radiance data well. A sensitivity analysis based on the singular value decomposition of the Jacobian matrix provided useful information for building the look up tables needed to estimate needle and canopy parameters. Canopy cover, fraction of bark in the plant area index, needle chlorophyll and dry matter content were estimated using the TOA CHRIS radiance. For comparison, the simulations, sensitivity analysis and parameter estimations were also conducted for the top of canopy (TOC) level, using atmospherically corrected CHRIS reflectance data. The results showed that the TOA approach performs as good as the TOC approach and allowed decreasing the ill-posedness for at least one stand.