Read me for Daily OLR CDR v01r02 CDR
Hai-Tien Lee (lee@umd.edu)
                                 Last updated 2014.12.16

The production of Daily OLR CDR requires geostationary observations.  The final version is 
generated with Gridsat CDR (labeled as "v01r02", while the interim version is generated 
with the GSIP OLR product (labeled as "v01r02-preliminary").

The Gridsat Data set starts on 1980, the geostationary observations did not attain global
coverage until 1998. 

Polar areas (about 60 degrees polewards) are not covered by geostationary observations. 
The daily OLR in these areas are derived with HIRS observations only. With the overscans 
over the polar areas, the local time samples are available for more than 12 hourly bins. 
However, due to the orbital configuration, the observations are mostly for the daytime 
for the northern polar region, while it is mostly for the nighttime for the southern polar 
region. The HIRS observations over these regions are integrated linearly with the available
hourly-bin'ed observations, without employing any diurnal models. 

Note for 2014 data:
The final Daily OLR CDR is available for year 1979 to 2013. The data generated
for 2014 is considered the "preliminary" or the "interim" product. The final Daily OLR CDR
for 2014 will be generated when the Gridsat CDR data is released for year 2014 in full.

Currently, the Gridsat CDR data is available only up to March 2014, while the global 
coverage of GSIP v3.1 data became avalable on Aug 8, 2014 (day 218). 
The period in between (day088-day217) is therefore generated with HIRS observations only, 
without geostationary data.  Data for this period will be re-derived when Gridsat CDR data 
become available.

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Summary of Daily OLR CDR data availability

Daily OLR CDR v01r02 19790101-20131231:
1979 - HIRS only
1980-2013 - HIRS blended with Gridsat v02r01 CDR 
            (Note that Gridsat does not provide full coverage until 1998)
            
Daily OLR CDR v01r02-preliminary 20140101-present:
2014.d001-d087 - HIRS blended with Gridsat v02r01 CDR
2014.d088-d217 - HIRS only
2014.d218-present - HIRS blended with GSIP v3.1
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History

2014.8.15
The GSIP v3.1 data is currently acquired internally through STAR developer (thanks to 
Istvan Laszlo and Vladimir Kondratovich). The GSIP v3.1 product will be acquired from 
NCDC CLASS when it is ready.

As the NESDIS/STAR GSIP production is not in an operational setting, data lost is possible.
This might cause some variations in the Daily OLR CDR for the given day.  The daily data
that was affected will be reprocessed whenever the satellite observations become available.

2014.9.17
GSIP data missing: 01Z-15Z 2014.09.16 (day 259)

2014.09.22
GSIP production interrupted, STAR computer failure, in repair. Expect GSIP data be missing 
for 9/22-29.2014.  May use GSIP V2 as surrogate.

2014.10.09
GSIP production resumed.
GSIP is missing for day 263-280, 2014.


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