Table 4. Detailed error budget for radiance method (Slater 1991)(a,b)

                                               Present        Anticipated
                                          ---------------   -----------------
                                           Error   Overall   Error  Overall
     Source                                 (%)    Error (%)  (%)   Error (%)
---------------------                      -----  --------  -----  ---------
Radiometer calibration                               2.5               1.6
  Panel calibration                          2.0             1.0
  Lamp calibration                           1.3             0.9
  Scale uncertainty                          1.2             0.8
  Transfer uncertainty                       0.5             0.5
  Lamp positioning                           0.3             0.3
  Lamp current stability                     0.5             0.5
  Voltage measurement error                  0.5             0.5
Measurement accuracy                                 1.3               1.2
  Data logger accuracy                       0.5             0.5
  Radiometer stability                       0.5             0.5
  Pointing angle errors (+8%)                1.1             1.0
Correction for altitude difference                  <0.1              <0.1
Uncertainty in reflectance-based method      5.0             3.0

TOTAL ERROR (RMS)                                    2.8               2.0

(a)  Private discussions with P. N. Slater, 1991, University of Arizona, Tucson, Arizona.
(b)  The estimates in Table 4 are more recent than those given in Table 2 and reflect successful efforts to reduce the uncertainty. Uncertainties are in % 
error with reference to exoatmospheric irradiance. First and third columns refer to values on the left. Second and fourth columns refer to the resultant effect 
of these uncertainties on radiance at the satellite detector.