SGP/SIRS/C1/E13 - Incorrect calibration coefficients

After the DIR changeout on 8/27, the DLH measurements at the central facility vary 
significantly between pyrgeometers by as much as 65 Wm^(-2).  It was discovered that the two 
downwelling pyrgeometers destined for C1 and E13 may have been swapped during installation.  
The instrument mentor is unsure of applied calibration coefficients during this DQR's 
time period.  Backing out new downwelling longwave irradiances would be difficult in this 
case. Fortunately, the problem period is less than a fortnight.

• inst_down_long_shaded_dome_resist
• inst_down_long_shaded_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)

• Raw data stream - documentation not supported

• inst_down_long_shaded_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)
• inst_down_long_shaded_dome_resist

• Raw data stream - documentation not supported

• inst_down_long_shaded_case_temp
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• down_long_hemisp_shaded_std
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• inst_down_long_shaded_dome_temp

• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• down_long_hemisp_shaded_std
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• inst_down_long_shaded_case_temp
• inst_down_long_shaded_dome_temp

SGP/SIRS/E13 - Monthly Report

:Data quality this site-month is good. The offset for the Global PSP is about -7 W/m^2.
The dominant problem here is the daytime 3 component problem. Direct and Diffuse are
always too high and Global is too low. The problem occurs around the time that the
testing regime switches from twilight to daytime testing regimes or from daytime to
twilight. The flags occur in significant numbers on the 1st - 5th, 7th - 20th, 24th - 
28th,
30th, and 31st. The failures vary in magnitude and duration. The worst flags for a 
particular

respect to this problem. Global goes below daytime empirical limits on both the 5th and
6th for substantial periods of time. Diffuse
also goes below daytime empirical limits on the 6th in the afternoon. Upwelling Longwave
is
below empirical limits on the 24th. This may not be a problem, as many sites exhibited
the same problem on the same night. Exceptionally cold temperatures may be the cause.

• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)

SGP/SIRS/E13 - Reprocessed: Longwave Calibration error

Modified pyrgeometer calibration procedures were implemented beginning in December 2003. 
These modified procedures introduced a calibration bias in the longwave data. The previous 
procedures were re-implemented at all sites between December 2005 and February 2006 to 
restore proper calibrations. 

The data collected while the incorrect procedures were in place have been reprocessed to 
remove the calibration bias.  The reprocessed 60 second averaged data are based on 3 
instantaneous 20 second data records rather than on 60 1 second instantaneous data records. 
Still, these data are considered far superior to the originally processed data. The 
reprocessed data were archived in October 2006.

• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Upwelling Longwave Hemispheric Net Infrared(up_long_netir)