Contact:

Dr. Charles N. Long
NOAA ESRL GMD/CIRES
325 Broadway Street
Boulder, CO 80305
email: Chuck.long@noaa.gov
Phone: 303-497-6056
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NOTE: The Integrated Surface Irradiance Study (ISIS) Network sites, with the exception
of the Madison (msn) site, include only downwelling total, direct and diffuse shortwave
(SW) measurements. Thus there is no pyrgeometer data with which to apply an IR loss 
correction. Instead, the average of the last half of the previous night and the first 
half of the following night has been added to all the data for that local day which
helps offset the IR loss but with larger uncertainty. These files use a "qadj" 
extension to denote the global SW has used a night average to help offset IR loss.

The Madison site had a pyrgeometer installed mid-June of 2009, and from then on the 
IR loss correction was applied. These latter files use a "qdat" extension. 

All other "missing" variables have been set so "-999.0" in order to preserve the
standard QCRad file format.

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NOTICE:These data products are made available to you by NOAA ESRL GMD
with the understanding that at the minimum you will clearly acknowledge 
the source. Journal references are given at the end of this document.

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QCRad outputs:

The output data files contain a header line, then the output data in rows starting with a 
date/time stamp, and followed by the variables in columns. The column headers and their
meanings are as follows:

Date		date in YYYYMMDD format, based on input time (UTC/LST/etc.)
Time		time of day in hhmm format,, based on input time (UTC/LST/etc.)
BESW		Best Estimate SW, sum of direct plus diffuse if both pass QC tests, else global SW if available (W/m^2)
GSW		total (global) SW from unshaded pyranometer (W/m^2)
DIF		measured downwelling diffuse SW (W/m^2)
DIR		measured downwelling direct SW (W/m^2)
SWup		upwelling SW from pyranometer (W/m^2)
LWdn		downwelling LW from pyrgeometer (W/m^2)
LWup		upwelling LW from pyrgeometer (W/m^2)
Ta		air temperature (K)  
VPrs 		vapor pressure  (mb)      
RH		Relative Humidity (%)
Prs		station pressure (same units as input)
LWdTc		Downwelling LW pyrgeometer case temperature (K)
LWdTd		Downwelling LW pyrgeometer dome temperature (K)
LWuTc		Upwelling LW pyrgeometer case temperature (K)
LWuTd		Upwelling LW pyrgeometer dome temperature (K)

qc1 through qc19 are quality testing flags, one for each test performed. See "QC_Rad3_flg_key.pdf" for details.
NOTE: If QC1, QC2, or QC3 flag value is set to "10" or greater, then that SW value was 
either "missing" or tested "bad" and the value was replaced by adding or subtracting the 
other two SW components to calculate the value. This calculated value is then tested just 
as the original value would have been, and might then be set to "bad" if the testing 
is not passed. The second digit (<10 value) represents the "normal" test flagging as described in
"QC_Rad3_flg_key.pdf."

gflg		type of IR loss correction applied to global SW, none/full dry/full moist/detector dry/det moist (0/1/2/3/4)
dflg		type of IR loss correction applied to diffuse SW, none/full dry/full moist/detector dry/det moist (0/1/2/3/4)
Z		Solar zenith angle (degrees)       
AU		Earth-Sun distance in astronomical units     
ClrSW		estimated clear-sky total downwelling SW, from user-set power law coefficient settings in configuration file  
DifCorr		IR loss correction applied to diffuse (shaded) SW measurements   
GSWCorr		IR loss correction applied to global (unshaded) SW measurements

There may be other variables that are "carried through" from the input files as set by the user in the configuration file.


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NOTE: The term "pyrgeometer detector flux" refers to the pyrgeometer signal (typically mV) 
times the sensitivity factor (or divided by the calibration factor). This value is 
what Dutton et al. 2001 call the instrument "netIR" in their diffuse correction paper.

 Dutton et al. Reference: 
Dutton, E. G., J. J. Michalsky, T. Stoffel, B. W. Forgan, J. Hickey, D. W. Nelson, 
T. L. Alberta, and I. Reda, 2001: Measurement of broadband diffuse solar irradiance 
using current commercial instrumentation with a correction for thermal offset errors. 
J. Atmos. and Ocean. Tech., 18(3), 297–314.

Other relevant references:

Long, C. N., and Y. Shi, (2008): An Automated Quality Assessment and Control Algorithm 
for Surface Radiation Measurements, TOASJ, 2, 23-37, doi: 10.2174/1874282300802010023.

Long, C. N. and Y. Shi, (2006): The QCRad Value Added Product: Surface Radiation 
Measurement Quality Control Testing, Including Climatologically Configurable Limits, 
Atmospheric Radiation Measurement Program Technical Report, ARM TR-074, 69 pp., 
Available via http://www.arm.gov.