PRELIMINARY EXAMINATION OF DAYTIME RADIATION DATA FROM TIROS III OVER CLOUDY REGIONS

Samples of listed radiation data for three channels (2, 3, and 5) from TIROS III are examined in conjunction with cloud photographs. Although the effective temperatures for the window channel (Channel 2) and the computed albedos for the visible channel (Channel 5) depict the clear and cloudy regions, apparent variations in cloud density are not described adequately by either channel alone. Most of the variability of Channel 5 data for selected regions with constant Channel 2 data appear to result from inhomogeneities in the viewed cloud cover. Computed albedos for Channel 5 did not display a dependence on scattering angle for scattering angles between 135 and 156 degrees. A proper interpretation of Channel 3 data awaits further study on the relative significance of scattering and absorption of solar radiation within the spectral region covered by Channel 3. Instrumental uncertainties remain in the data, especially for Channel 3 and to a lesser extent for Channel 5. Consequently, analyses of data from these channels emphasize relative variations rather than absolute values. (Author)