TWP/GNDRAD/C2 - IRT problem

The GNDRAD IRT exhibited a positive bias compared to the PIR from 2100 to 0700 UTC each 
day. The problem was corrected by removing the signal cable, cleaning the contacts, and 
reconnecting the cable.

• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature, Standard Deviation(sfc_ir_temp_std)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Effective Surface (Skin) Temperature(sfc_ir_temp)

TWP/GNDRAD/C2 - incorrect IRT calibration

When the GNDRAD data logger was upgraded, the calibration offset for the IRT was initially 
incorrect.

• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Effective Surface (Skin) Temperature(sfc_ir_temp)

TWP/GNDRAD/C2 - IRT connector

The IRT had a problem with the connector of either the signal or power cable which 
produced an output of 0 volts equivalent to a measurement of 223K. The problem was corrected 
when the connectors were cleaned and tightened.

• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature, Standard Deviation(sfc_ir_temp_std)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Effective Surface (Skin) Temperature(sfc_ir_temp)

TWP/GNDRAD/C2 - Reprocess: 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 are 
being reprocessing to remove the calibration bias.  Note, this also affected standard 
deviation, maximum and minimum data fields.

• Upwelling (10 meter) Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)

TWP/GNDRAD/C2 - IRT signal

When the other GNDRAD radiometers were replaced on 12/3/2006, the quality of the IRT 
signal began to degrade until 12/26 when it became unusable. The instrument was replaced on 
2/4/2007.

• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature, Standard Deviation(sfc_ir_temp_std)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Effective Surface (Skin) Temperature(sfc_ir_temp)

TWP/GNDRAD/C2 - Reprocess: IRT calibration

The configuration of the IRT was set to that used at TWP/C3. This caused the calibration 
of the data to be wrong. It was corrected by reconfiguring the IRT to match the datalogger 
program.
   
These data can be reprocessed and corrected by adding 10K, i.e. sfc_ir_temp(new) = 
sfc_ir_temp(old) + 10K.

• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)
• Effective Surface (Skin) Temperature(sfc_ir_temp)

TWP/GNDRAD/C2 - Reprocessed: Incorrect calibration

The Gndrad PSP was changed out 11/25 but the datalogger program was not updated until 
11/30.

PSP #31293 installed 20071125.2202.  Correct calibration coefficient = 123.46.

Reprocessed to correct upwelling shortwave hemispheric irradiance (US) by:
US(new) = (US(old) / 123.56 ) * 123.46

Reprocessing completed March 2008.

• Upwelling (10 meter) Shortwave Hemispheric Irradiance, Pyranometer(up_short_hemisp)
• Upwelling (10 meter) Shortwave Hemispheric Irradiance, Pyranometer, Maxima(up_short_hemisp_max)
• Upwelling (10 meter) Shortwave Hemispheric Irradiance, Pyranometer, Standard
  Deviation(up_short_hemisp_std)
• Upwelling (10 meter) Shortwave Hemispheric Irradiance, Pyranometer, Minima(up_short_hemisp_min)

• Instantaneous Upwelling Shortwave Hemispheric Irradiance, Pyranometer(inst_up_short_hemisp)