Updates to Appendix B in NOAA TM NESS 107
      for NOAA-F/9 and NOAA-H/11


The following information is an amendment to Appendix B:

1.   The pre-launch values of the calibration coefficients for
     the visible channels of the NOAA-H/11 AVHRR has been
     revised.  The new values are based on a more recent    
     (April 1989) calibration of the integrating sphere, the
     secondary standard used at ITT to calibrate the AVHRR.    
     The orginally published values are based on a November 1987
     sphere calibration, which was inconsistent with previous and
     subsequent sphere calibrations.

     The new values are:

                         G              I


     Channel 1           0.095          -3.78
     Channel 2           0.090          -3.60

     Although this table presents a better estimate of the
     calibration of the NOAA-11 AVHRR before launch, the
     calibration may vary after launch.  There is evidence that
     the G coefficient for the AVHRR's on earlier satellites
     changed as much as 5 to 10% per year after launch.  We do
     not yet have a good estimate of the in-orbit NOAA-11 AVHRR
     calibration.

2.   A preliminary version of the Appendix B for NOAA-H/11 was
     issued with erroneous values of the central wavenumbers for
     the infrared channels of the AVHRR (FM203).  
     The correct values are as follows:

     TEMP      CHANNEL 3      CHANNEL 4      CHANNEL 5

     180-225    2663.50        926.81         841.40
     225-275    2668.15        927.36         841.81
     275-320    2671.40        927.83         842.20
     270-310    2670.96        927.75         842.14

3.   In the Appendix B for NOAA-F/9 in NOAA Tech. Memo NESS 107 -
     Rev. 1 (Oct. 1988) there is a typographical error on page B5
     in the Channel 5 Nonlinearity Correction Table.  For a
     target temperature of 305 degrees K and a blackbody
     temperature of 10 degrees C, the value of the correction
     should be 0.7 degrees C, not 1.1 degrees C.