TWP/SKYRAD/C2 - Direct Normal reading too low

The NIP (direct_normal shortwave irradiance) measurement was reading too low during this 
time period.  No TWP Ops documentation could be found to determine the cause but data 
review indicate that the NIP appeared to be reading low by about 25W/m2 during this period.  
The NIP data had well defined steps in irradiance when compared to three component checks 
indicating the problem period.

• Raw data stream - documentation not supported

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

• inst_direct_normal

TWP/SKYRAD/C2 - Tracker failure

Tracker failed to wake up on 12/17.  Ops reset tracker on 12/21.  

The affected instruments are the 8-48 (down_short_diffuse) and NIP (direct_normal) 
shortwave instruments.

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

• inst_direct_normal
• inst_diffuse

TWP/SKYRAD/C2 - Tracker inoperative

The tracker failed in park position.  Tracker was replaced 5/14 but did not resume fully 
normal operation until 5/18.

The down_short_diffuse and short_direct_normal data are directly affected by this failure. 
 These data are not recoverable.

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

• inst_direct_normal
• inst_diffuse

TWP/SKYRAD/C2 - Instrument grounding problem

During this time period the IRT analog output line appears to have adversely affected the 
skyrad datalogger grounding.  This resulted in intermittent anomalous readings across all 
skyrad datalogger channels including logger voltage.

• inst_down_long_hemisp2_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• Radiation, shortwave, downwelling total hemispheric irradiance, 1-min avg(down_short_hemisp)
• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_std
• down_long_hemisp1_min
• inst_down_long_hemisp2_tp
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_long_hemisp1_max
• inst_down_long_hemisp1_tp
• down_long_hemisp2_std
• down_short_diffuse_hemisp_std
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• sky_ir_temp_min
• down_short_hemisp_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• down_long_hemisp1_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• inst_down_long_hemisp1_dome_temp
• short_direct_normal_std
• down_long_hemisp2_max
• down_long_hemisp2_min
• inst_down_long_hemisp2_dome_temp
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Maxima(down_short_hemisp_max)
• sky_ir_temp_max
• Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyranometer, Minima(down_short_hemisp_min)
• inst_down_long_hemisp1_case_temp
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)

• inst_diffuse
• inst_down_long_hemisp2_tp
• inst_direct_normal
• inst_down_long_hemisp1_tp
• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp2_case_resist
• inst_sky_ir_signal
• inst_down_long_hemisp2_dome_resist
• inst_global
• inst_down_long_hemisp1_dome_resist

TWP/SKYRAD/C2 - IRT Missing

After a significant rain event on 5/25, the IRT was found to be the cause of grounding 
problems with the SKYRAD datalogger that was affecting the measurements from other 
instruments. This problem was solved by removing the IRT signal from the datalogger. The problem 
was suspected to be with either the power/signal cable or the internal grounding of the 
IRT. The problem was corrected when both the IRT and analog cable were replaced on 6/23.

• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_std
• sky_ir_temp_max
• sky_ir_temp_min

• inst_sky_ir_signal

TWP/SKYRAD/C2 - Reprocess: IRT configuration

When the IRT was replaced, it was not initially configured correctly.  The data will be 
reprocessed.

• Temperature, Sky Infra-Red(sky_ir_temp)
• sky_ir_temp_max
• sky_ir_temp_min

TWP/SKYRAD/C2 - Suspect PIR1 data

PIR1 was exhibiting unusual data excursions during the specified time ranges and data are 
suspect.  The problem spontaneously resolved on October 11th without site ops action.  
The problem has not returned.

• down_long_hemisp1_max
• down_long_hemisp1_std
• down_long_hemisp1_min
• inst_down_long_hemisp1_dome_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• inst_down_long_hemisp1_case_temp

• inst_down_long_hemisp1_case_resist
• inst_down_long_hemisp1_dome_resist
• inst_down_long_hemisp1_tp