SGP/SIRS/E21 - Failed Tracker

During the time ranges specified the SIRS solar tracker had failed for unspecified 
reasons.  Measurements of short_direct_normal (NIP) and down_short_diffuse_hemisp (8-48) will be 
incorrect and not recoverable.  Longwave data are unaffected.

• inst_diffuse
• inst_direct_normal

• down_short_diffuse_hemisp_std
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)

SGP/SIRS/E21 - Ventilator Fan Failure

Start time is uncertain due to length of time this problem existed.  During the time frame 
specified the PSP (down_short_hemisp) and 8-48 (down_short_diffuse_hemisp) ventilator 
fans failed. PM replaced the fans 7/1/2008 1500. 
Ventilator failure does adversely affect thermopile radiometer measurements but the extent 
has not been quantified. The 8-48 is significantly less affected than the PSP. Mentor 
suggests using component sum method detailed in SIRS
instrument handbook where down_short_hemisp = down_short_diffuse +
short_direct_normal * cos (zenith angle) for each time record.

• inst_diffuse
• inst_global

• Raw data stream - documentation not supported

• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• down_short_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)

SGP/SIRS/E21 - Tracker inoperative

The solar tracker at this site had numerous failures over the time range of this DQR.  The 
result is non-recoverable data for any direct normal (NIP) or diffuse (8-48) broadband 
measurement.  Longwave data is generally unaffected by such failures.

• inst_diffuse
• inst_direct_normal

• down_short_diffuse_hemisp_std
• short_direct_normal_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)

SGP/SIRS/E21 - Tracker failure

First apparent on 03/26, the short_direct_normal values were incorrect after approximately 
1700GMT each day. The tracker was found to have excessive clock drift and was reset by 
site ops on 05/04/2010 and returned to service at 1935GMT. The down_short_diffuse_hemisp 
values appear unaffected by the tracker misalignment.

The short_direct_normal data values are suspect after approximately 1800GMT each day from 
03/26 to 04/26 and after 1700GMT from 04/27 to the end of the period.  The 
short_direct_normal data are not recoverable but can be calculated indirectly using the following 
relationship for each minute of data:
down_short_hemsip = short_direct_normal * cos(zenith angle) + down_short_diffuse

• inst_direct_normal

• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)

SGP/SIRS/E21 - Reprocessing: TimeCheck Error

The EF data system lost communication with the GPS likely starting on or around June 7th, 
the max time set For E21 was -5.04 sec. Since then, it has been increasing steadily:

Jun 8  Offset:    -267.449039
Jun 9  Offset:    -541.038624
Jun 10 Offset:    -814.469141
Jun 11 Offset:    -1076.862114
Jun 12 Offset:    -1350.330223
Jun 13 Offset:    -1623.639335
Jun 14 Offset:    -1897.047754
Jun 15 Offset:    -2170.552312
Jun 16 Offset:    -2422.130746
Jun 17 Offset:    -2684.607495
Jun 18 - Jun 22 (unknown)
Jun 23 Offset:    -4204.730579

If the E21 system clock drifts the E21 Datalogger clocks will be set to the same incorrect 
time. SIRS irradiance data will be correct but the corresponding time stamp cannot be 
accurately known or simply corrected for.

• inst_diffuse
• inst_up_long_hemisp_tp
• time_offset
• inst_up_short_hemisp
• inst_up_long_case_resist
• lat
• alt
• inst_down_long_shaded_case_resist
• lon
• inst_down_long_shaded_dome_resist
• inst_global
• base_time
• inst_direct_normal
• inst_up_long_dome_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)

• Raw data stream - documentation not supported

• up_short_hemisp_std
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Upwelling Longwave Hemispheric Net Infrared(up_long_netir)
• down_long_hemisp_shaded_std
• lat
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Maxima(up_short_hemisp_max)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• inst_down_long_shaded_case_temp
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• time_offset
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)
• lon
• down_short_diffuse_hemisp_std
• inst_up_long_case_temp
• base_time
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• up_long_hemisp_std
• alt
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• down_short_hemisp_std
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• inst_up_long_dome_temp
• short_direct_normal_std
• inst_down_long_shaded_dome_temp
• vBatt
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)

SGP/SIRS/E21 - NIP data intermittently missing or incorrect

The short_direct_normal data was showing negative values (<-50 W/m^2)(during first time 
range) and missing value (-9999)(during second time range) each day a little after sunrise. 
Primarily between the hours of 11:00 - 14:00 GMT. Site Ops repaired a broken wire in the 
NIP cable and data appeared OK after the repair.

NIP data are not recoverable. Users can calculate short_direct normal component using:
short_direct_normal = (down_short_hemisp - down_short_diffuse_hemisp)/cos(zenith angle)

• inst_direct_normal

• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)