SGP/IRT25m/C1 - Odd Instantaneous Surface IRT data

The sgpirt25mC1.a1 data for variable
   inst_sfc_ir_temp
look odd.  Each day, the first two records and the last 58 records have reasonable data 
but the remaining records are all zero. This behavior is seen all the way back to 20021121 
when the instantaneous variables were added to the sgpirt25mC1.a1 data stream.

The other instantaneous data variables do not show a similar pattern and the 60 sec 
sfc_ir_temp data look reasonable.

• Instantaneous Surface Infra-red Temperature(inst_sfc_ir_temp)

SGP/IRT25m/C1 - Reprocess: up_short_hemisp needs -1 multiplier

The upwelling hemispheric shortwave measurement
   in the SGP.C1 IRT25m data streams for the time
   period noted requires a (-1) multiplier to correct
   for swapped connections at installation.

• inst_up_short_hemisp_tp

• inst_up_short_hemisp
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)
• up_short_hemisp_std
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)

• inst_up_short_hemisp
• up_short_hemisp_std
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)

• Raw data stream - documentation not supported

SGP/IRT25m/C1 - error in data logger program

On 12/16/2002, the logger software for the IRT25m was
inappropriately edited. This resulted in incorrect instantaneous
values at 20 and 40 seconds after each minute and incorrect 
calculation of 60-second averaged instantaneous values (because
the 20 and 40 second values are two of three instantaneous
values used to calculate this average). On 5/21/2003, the data
logger program was corrected.

• inst_up_long_case_resist
• inst_up_long_dome_resist
• Instantaneous Surface Infra-red Temperature(inst_sfc_ir_temp)
• inst_up_short_hemisp_tp
• inst_up_long_hemisp_tp

• inst_up_long_dome_temp
• inst_up_long_case_temp
• inst_up_short_hemisp
• inst_case_temp
• Instantaneous Upwelling Longwave Hemispheric Irradiance, Pyrgeometer(inst_up_long_hemisp)
• Instantaneous Surface Infra-red Temperature(inst_sfc_ir_temp)
• inst_dome_temp

SGP/IRT25m/C1 - Corrupt instananeous dome and case temp data

In the data stream sgpirt25mC1.a1, the variables
   inst_dome_temp
   inst_case_temp
changed to
   inst_up_long_dome_temp
   inst_up_long_case_temp
beginning with the file from 20030220. 

The data for these two variables appears to be corrupt
in the 20030219 file after 1620, likely due to the variable 
name changes.  The data for these two variables appear to
be reasonable in the 20030220 file and beyond.

• inst_case_temp
• inst_dome_temp

SGP/IRT25m/C1 - Upwelling bias due to dirt on lens

The upwelling IRT at 25m exhibited a positive bias compared to the PIR. The problem was 
corrected when the lens was cleaned.

• sfc_ir_temp_std
• Surface Infra-Red Temperature Minima(sfc_ir_temp_min)
• Instantaneous Surface Infra-red Temperature(inst_sfc_ir_temp)
• Effective Surface (Skin) Temperature(sfc_ir_temp)
• Surface Infra-Red Temperature Maxima(sfc_ir_temp_max)

• Raw data stream - documentation not supported

SGP/IRT/C1 - 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.

• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Instantaneous Upwelling Longwave Hemispheric Irradiance, Pyrgeometer(inst_up_long_hemisp)