SGP/QCRAD/E15 - Direct normal irradiance intermittently low

Direct normal irradiance measurements appear to be intermittently too low and possibly 
incorrect during this time period. The cause is not known. No instrument DQRs currently 
exist describing the problem.

• Irradiance, shortwave, direct normal, pyrheliometer(short_direct_normal)

SGP/QCRAD/C1 - Reprocess: SW data require -1 multipler

Magnitude of data are correct, however, 2 wires were crossed producing negative values for 
SW Global Down, SW Global Up, SW Direct Normal, and SW Diffuse Down. Problem has been 
fixed at site.

Users of this data should multiply by -1 to get the correct values for SW Global Down, SW 
Global Up, SW Direct Normal, and SW Diffuse Down. Data will be reprocessed.

Documented in instrument DQR D000919.1.

• Best Estimate Global Downwelling Shortwave Hemispheric Irradiance(BestEstimate_down_short_hemisp)
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer(down_short_diffuse_hemisp)
• Irradiance, shortwave, direct normal, pyrheliometer(short_direct_normal)
• Irradiance, shortwave, upwelling, hemispheric, 10 meter(up_short_hemisp)

SGP/QCRAD/C1 - Upwelling SW cable problem

Starting 11/13/2006, the C1 SIRS Upwelling Shortwave (up_short_hemisp) started to show 
large differences in comparison to co-located E13 SIRS and C1 IRT25m.  After much 
troubleshooting and gnashing of teeth it was discovered that rodents had chewed through the 
instrument cables at the bottom of the tilt tower. Cables were replaced 01/23/2007 1930GMT.

Documented in instrument DQR D061121.2

• Irradiance, shortwave, upwelling, hemispheric, 10 meter(up_short_hemisp)

SGP/QCRAD/C1 - Sensor cable problem

Beginning October 3, 2007, the upwelling longwave irradiance (up_long_hemisp, aka "UIR") 
started to spike to unreasonable values positively offset from the co-located E13 by over 
100W/m2.  On January 17 2008 the UIR values become consistently bad due to bad UIR dome 
thermistor wiring.  Problem appears as a resistive offset in the dome thermistor but due 
to nature of failure (unknown cable problem) data correction would not yield any better 
data than the co-located E13 UIR instrument that is known to be operating correctly. 
Instrument cable replacement on 4/22 fixed the problem.

Thermopile data (netIR) from this instrument is good.  However, incoming irradiance data 
is not correctable due to bad UIR dome thermistor wiring within the instrument cable. 

Documented in instrument DQR D071022.4.

• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)

SGP/QCRAD/C1 - SW direct normal data drop out

NIP cable had failed during this time period.  Short_direct_normal data are not 
recoverable during this time period. However, it can be reconstructed using the following formula 
for each one minute data:
   short_direct_normal = (down_short_hemisp-down_short_diffuse_hemisp)/cos(zenith angle)

Documented in instrument DQR D090623.1

• Irradiance, shortwave, direct normal, pyrheliometer(short_direct_normal)

SGP/QCRAD/C1 - Failed upwelling SW cable

The upwelling shortwave hemispheric (up_short_hemisp) data were missing or incorrect due 
to a bad cable.  Cable was replaced on 6/30 and the problem was resolved.

Documented in instrument DQR D100701.1

• Irradiance, shortwave, upwelling, hemispheric, 10 meter(up_short_hemisp)

SGP/QCRAD/C1 - NIP failure

The short_direct_normal (NIP instrument) cable failed during this time period.	Data are 
not recoverable.

Users can derive an estimate of direct normal values using the following formula:
short_direct_normal = (down_short_hemisp - down_short_diffuse_hemisp)/cos(zenith angle)

Documented in instrument DQR D110628.2

• Irradiance, shortwave, direct normal, pyrheliometer(short_direct_normal)

SGP/QCRAD/C1 - Case and dome temperatures not available

Longwave downwelling and upwelling case and dome temperatures are not available during 
this time period because they were not kept in the sirs.a1 files and sirs.b1 files are not 
available. This means that some longwave tests and corrections can't be applied.

• LWupTd
• LWupTc
• LWdnTd
• LWdnTc
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Downwelling Longwave Hemispheric Irradiance, Pyrgeometer(down_long_hemisp)

SGP/QCRAD/C1 - Reprocess: Incorrect quality control values

qc_up_long_hemisp & qc_up_short_hemisp = 0 when they should be 1.

• qc_up_short_hemisp
• qc_up_long_hemisp

SGP/QCRAD/C1 - Reprocess: Error in processing code

End to end reprocess of qcradbrs data has been accomplished but the data has not been 
submitted to the ARM Archive yet. Problems found in the original data include:

1. upwelling data found in days where no brs1dutt data were available. This was caused by 
a bug in the original code which used sirs1dutt data as input when brs1dutt data is 
missing. In the reprocessed data there are simply no output files on these days.

2. A bug in the original code caused error in the generic IR correction of GSW, which 
affected mostly the nighttime data in the output.

• qc_LWupTc
• qc_LWupTd
• qc_up_short_hemisp
• LWupTc
• LWupTd
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• source_BestEstimate_down_short_hemisp
• qc_BestEstimate_down_short_hemisp
• qc_up_long_hemisp
• Best Estimate Global Downwelling Shortwave Hemispheric Irradiance(BestEstimate_down_short_hemisp)
• Irradiance, shortwave, upwelling, hemispheric, 10 meter(up_short_hemisp)