Results of a remote sensing validation experiment are reported. Above cloud measurements of reflected solar radiation were made with a grating spectrometer, co-incident below cloud measurements of emitted thermal radiation with a FTIR spectrometer. Two remote sensing algorithms based on radiative transfer simulations were employed to retrieve visible optical depths and effective droplet radii. The values derived from both measurements are consistent and indicative for the cloud vertical structure. ¿ 2000 American Geophysical Union