A detailed description of the clear-sky radiance retrieval and clear-sky greenhouse parameters have been published (Frey et al, 1995). Frey et. al., (1995) used HIRS observations to investigate the spectral variation of the greenhouse effect of water vapor. This paper will present the spatial and temporal variability of a clear-sky greenhouse parameter, using the MODIS. Results are compared to the HIRS/2 study of Frey et al.