Weekly Report on GOES-14 PLT Science Test

							   Weekly Report on
GOES-14 PLT Science Test

       NOAA / NESDIS / STAR
  X. Wu, G. Rancic, F. Yu, M. Grotenhuis
           December 14, 2009

                                           1
   Initial Post-Launch Calibration of
GOES-14 Imager Visible Channel by Moon
Purpose:
 Verify pre-launch calibration
 Establish benchmark for trending


Method:
 Vicarious calibration based on lunar observations.


Data:
 GOES-14 lunar observations on 08/10/2009.


Analysis:
 Lunar irradiances are calculated per Wu & Yu (2006).
 ROLO predicted irradiances are obtained (courtesy of Dr. Tom Stone of
  USGS).
                                                                      2
                                                  GOES-14 observed and ROLO model
                                                predicted lunar irradiances and their ratios
                                                                                   GOES-14 Lunar Calibration

                                                                                      GOES     ROLO    Ratio

                                               0.92                                                                                    1.030


                                                                               3. The ratio is not constant, likely due to
                                               0.90
                                                                               angular dependence of scan mirror reflectance           1.020
Irradiance (W m^-2 um^-1) or Ratio (no unit)




                                                                               that will be addressed separately.




                                                                                                                                                GOES/ROLO Ratio (no unit)
                                               0.88                                                                                    1.010


                                                                                       2. The measured irradiance
                                               0.86
                                                                                       generally follows the                           1.000
                                                                                       predicted trend.
                                                          1. The predicted lunar
                                                          irradiance decreases
                                               0.84                                                                                    0.990
                                                          with the waning moon

                                               0.82                                                                                     0.980
                                                   20.4      20.6     20.8     21.0           21.2             21.4   21.6   21.8   22.0
                                                                                    Time (UTC on 10 Aug 2009)
                                                                                                                                                                            3
              Preliminary results
   The GOES-14 Imager visible channel appears
    ~1% brighter than predicted by the ROLO model.
   Well within the uncertainty of Lunar based post-
    lunch calibration (>2%).
   It has been observed for several AVHRR’s that
    measurements are initially brighter then expected.
   Further evaluation by other vicarious calibration
    will follow.


                                                    4