16 The Past, Present, and Future of the AVHRR Pathfinder SST Program
281
Fig. 16.2 Climatological
mean SST for week 50, based
on Pathfinder Version 5 data
is available on line. 1 An example image, generated from a climatological mean of
Pathfinder Version 5 SST, is shown in Fig. 16.2.
The following steps provide the details on the current state of the Pathfinder
processing system. Boldface items highlight the data and information provided to
the processing system.
Step 1: Ingestion, calibration, and navigation of GAC data
1.1. Calibrate and convert AVHRR digital counts for channels 1–5 to
radiances
1.1.1. Obtain AVHRR channels 1–5 radiometer count data from
NOAA and University of Miami collections of GAC data.
1.1.2. For channels 1 and 2, use pre-launch calibration coefficients to
perform a linear counts-to-radiance conversion, followed by a
correction for temporal changes using sensor decay rate data
and then a correction for inter-satellite differences using intersatellite standardization data to a NOAA-9 reference, both of
which use Libyan desert target area data.
1.1.3. For channels 3, 4, and 5 use both the above pre-launch
calibration data and onboard blackbody (space view and sensor
base plate) data to perform a non-linear counts-to-radiance
conversion.
1 At http://pathfinder.nodc.noaa.gov
281
Fig. 16.2 Climatological
mean SST for week 50, based
on Pathfinder Version 5 data
is available on line. 1 An example image, generated from a climatological mean of
Pathfinder Version 5 SST, is shown in Fig. 16.2.
The following steps provide the details on the current state of the Pathfinder
processing system. Boldface items highlight the data and information provided to
the processing system.
Step 1: Ingestion, calibration, and navigation of GAC data
1.1. Calibrate and convert AVHRR digital counts for channels 1–5 to
radiances
1.1.1. Obtain AVHRR channels 1–5 radiometer count data from
NOAA and University of Miami collections of GAC data.
1.1.2. For channels 1 and 2, use pre-launch calibration coefficients to
perform a linear counts-to-radiance conversion, followed by a
correction for temporal changes using sensor decay rate data
and then a correction for inter-satellite differences using intersatellite standardization data to a NOAA-9 reference, both of
which use Libyan desert target area data.
1.1.3. For channels 3, 4, and 5 use both the above pre-launch
calibration data and onboard blackbody (space view and sensor
base plate) data to perform a non-linear counts-to-radiance
conversion.
1 At http://pathfinder.nodc.noaa.gov