SGP/SIRS/E9 - PSP dome contamination

Measured values of diffuse shortwave downwelling radiation fluctuated below derived values 
of downwelling shortwave radiation by 50 W/m^2 during the afternoon hours under clear 
conditions. 

SMOS precipitation and wind speed data reveals rain and wind the night before on 02/20/03 
0100 GMT probably contaminated the PSP dome with dirt.

Precipitation of .25mm on 02/23/04 0300 seems to have effectively cleared the PSP dome 
since PSP data on 02/24/04 compares correctly to direct and diffuse components.

• inst_global

• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• down_short_hemisp_std

• Raw data stream - documentation not supported

SGP/SIRS/E9 - Unknown -failed PSP ventilator fan

Downwelling shortwave hemispheric (DSH) readings appear to have a slight to moderate 
negative offset from derived DSH values.  At night, this negative offset causes qc flags 
(since values are below the minimum threshold of -10 W/m^2).  Differences between derived and 
actual DSH values are sometimes on the order of 50 W/m^2 due to this offset. 
The offset was discovered to be due to a failed ventilator fan which is used to clear the 
dome of the PSP, the instrument which measures the DSH.  The ventilator likely seized or 
was intermittent and heated the PSP base giving an erroneous DSH reading.  Field techs 
replaced the fan on 01/25/2005 1745GMT.  The DSH has been reading normally since that time.

• inst_global

• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• down_short_hemisp_std

• Raw data stream - documentation not supported

SGP/SIRS/E9 - 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 instanteous 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)
• Upwelling Longwave Hemispheric Net Infrared(up_long_netir)
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)