By John Porter University of Hawaii porter@soest.hawaii.edu During ACE1 measurements of upwelling radiance were measured on the NCAR C130 aircraft. The data was collected with a spectrophotometer covering the range from 311 to ~1132 nm. The data above 420 and below 900 nm had better signal to noise and time averaging is encouraged if wavelengths above and below these values are used. Calibration was carried out on the system in the plane at the beginning and end of the experiment. These values were within 1% so that the system was stable throughout the experiment. Absolute calibration of the radiance measurements is %6. This is based on tests with three independent NIST traceable standards. The system worked well throughout the experiment when measuring clear sky upwelling radiance. Although our goal was not to study cloud reflected radiance, the measurements obtained during ACE1 can be used for this purpose. We suggest those interested in studying cloud reflectance with this data contact John Porter for further considerations on this matter as well as any other questions. File name convention example: f05all1 = flight 5 f32all1 = flight 32 Each line of the file contains day of year, gain, integration time, (256 radiance values in W/m2 sr nm) The wavelength of each channel is given by the following equation: wavelength (nm) = C0 + C1*I + C2*I^2 + C3*I^3 + C4*I^4 where C0 = 311.14 C1 = 3.298980475 C2 = 2.006471214*10^-4 C3 = 1.977325295*10^-6 C4 = 2.422430614*10^-9 and (I=0 to 255)