| Description: | 'Albedo' is derived from the measurements of Channels
1 and 2 of the AVHRR (Advanced Very High Resolution
Radiometer) on the NOAA-14 satellite. The
time-dependent calibration coefficients are provided
to the XDC by SeaSpace, which in turn obtains them
from NOAA NESDIS website
http://140.90.207.25:8080/EBB/ml/niccal2.html. These
are based on the formulae published by Rao and Chen in
1996 (Rao, C.R.N., and J. Chen, 1996: Post-launch
calibration of the visible and near-infrared channels
of the Advanced Very High Resolution Radiometer on the
NOAA-14 spacecraft. International Journal of Remote
Sensing, 17, 2743-2747.)
Rao provided TIME DEPENDENT correction formulas for the
period.
Channel 1: CF1 = (1.015 - 8.8*10-5 d + 1.3*10-8 d2 )
Channel 2: CF2 = (1.037 - 1.8*10-4 d + 3.2*10-8 d2 )
where d is days since launch of NOAA-14 (1994-12-30).
Xiong Xiaozhen of the University of Alaska has told us that
"The new coefficients is consistent with what I found
and applied in the thesis."
In December 1999, Rao and Chen published a new
calibration for Channels 1 and 2 for the NOAA-14 AVHRR
in the International Journal of Remote Sensing (Vol
20, 3485-3491; see also
http://140.90.207.25:8080/EBB/ml/niccal1.html). This
corrects an overestimate of albedo that results from
their earlier calibration expression. |