SGP/SIRS/E9 - Tracker failure

The solar tracker was not functioning during these periods. OPS found the solar tracker 
not running, power cycled suntracker and it normal operations resumed. 

Data from instruments directly reliant on tracker operations (short_direct_normal and 
down_short_diffuse_hemisp) are not recoverable.

• inst_direct_normal
• inst_diffuse

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

SGP/SIRS/C1 - Reprocess: Incorrect downwelling longwave calibration coefficient

The calibration coeff and serial number for the down_long_hemisp_shaded was incorrect 
during the period specified. 

Correct Instrument serial number = 30010F3 
                              K1 = 0.3125
Incorrect Instrument serial number = 30690F3 
                                K1 = 0.2762
 
Data will be reprocessed.

To correct the one minute data b1 datastream follow the procedure below:
1) Obtain the following variables from the 20s datastream for each one minute of the 
affected
time range:
  inst_down_long_shaded_dome_resist (Rd)
  inst_down_long_shaded_case_resist (Rc)
  inst_down_long_hemisp_shaded_tp (tpDIR_mV)
					 
2) using the 20s tp voltage in mV convert to uV.
  tpDIR[uV] = inst_down_long_hemisp_shaded_tp[mV]*1000[uV/mV]

3) For each 20s data entry convert Rd and Rc to temperature
  Td =1/ (a0 + (a1*LN (Rd*1000) + (a2*LN (Rd*1000)^3)))
  Tc = 1/ (a0 + (a1*LN (Rc*1000) + (a2*LN (Rc*1000)^3)))
  where a0 = 0.0010295 
	a1 = 0.0002391
	a2 = 0.0000001568

4) Apply for each 20s data entry: (correct k1=0.3125)
  WinDIR(W/m^2)= [0.3125*tpDIR] + Sigma*Tc^4 -4*Sigma*(Td^4 - Tc^4)
  where, 
        WinDIR = Corrected down_long_hemisp_shaded (W/m^2)
        Sigma =	5.6704E-8 (Stefan-Boltzman Constant)

				      
5) Generate new 1 minute average from the three 20-second measurements

• inst_down_long_shaded_dome_resist
• inst_down_long_shaded_case_resist
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)

• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_long_hemisp_shaded_std
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
• inst_down_long_shaded_case_temp
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• inst_down_long_shaded_dome_temp

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)

SGP/SIRS/E37 - Instrument problem

The short_direct_normal value is having some issues.  Data is missing starting 0123 GMT on 
6/30 through current.  Data is either close to 0 on clear days or not following normal 
trends prior to the aforementioned period.  down_short_diffuse_hemisp is also suffering 
from some issues.  

Problem looks to have started on 6/17, but may have started earlier than that.

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

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

SGP/SIRS/E37 - Tracker and NIP repairs

The solar tracker at this site was replaced; communication problems with the replacement 
tracker were performed 7/2/12; NIP repair performed 7/9/12. Data for direct normal (NIP) 
and diffuse (8-48) are incorrect and nonrecoverable during affected period. Longwave data 
are generally unaffected by such tracker failures.

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

• inst_diffuse
• inst_direct_normal

SGP/SIRS/E35 - Upwelling longwave resistor problem

The up_long_hemisp was missing or showing intermittent spikes for the specified period. 
OPS discovered a bad UIR resistor and replaced it with new resistor.

• inst_up_long_hemisp_tp
• inst_up_long_dome_resist
• inst_up_long_case_resist

• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• inst_up_long_case_temp
• Upwelling Longwave Hemispheric Net Infrared(up_long_netir)
• up_long_hemisp_std
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)
• inst_up_long_dome_temp
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)

SGP/SIRS/E38 - Instrument problem

up_long_hemisp shows large steps and offsets in values (greater than physically possible 
incoming radiation) that were eventually atributed to a bad instrument cable connection.
The up_long_hemsip values during the time range specified were intermittant, varying from 
10 to 100% of any given day.

• inst_up_long_hemisp_tp
• inst_up_long_case_resist
• inst_up_long_dome_resist

• up_long_hemisp_std
• Upwelling Longwave Hemispheric Net Infrared(up_long_netir)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• inst_up_long_case_temp
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• inst_up_long_dome_temp

SGP/SIRS/E31 - Instrument problem

Up_long_hemisp and up_long_netir are missing, noisy, or suspect during this time period.

• inst_up_long_case_resist
• inst_up_long_hemisp_tp
• inst_up_long_dome_resist

• up_long_hemisp_std
• Upwelling Longwave Hemispheric Net Infrared(up_long_netir)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Maxima(up_long_hemisp_max)
• inst_up_long_case_temp
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• inst_up_long_dome_temp
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)

SGP/SIRS/E31 - Tracker Failure

All tracker related datastreams are affected: short_direct_normal (NIP), 
down_short_diffuse_hemispheric (8-48), and possibly the down_long_hemisp_shaded (PIR) although it is not 
apparent in the reviewed data for the affected timeframe.

• inst_down_long_shaded_case_resist
• inst_diffuse
• inst_direct_normal
• Irradiance, longwave, downwelling, hemispheric, thermopile (Shaded Pyrgeometer1)(inst_down_long_hemisp_shaded_tp)
• inst_down_long_shaded_dome_resist

• down_long_hemisp_shaded_std
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• inst_down_long_shaded_dome_temp
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• down_short_diffuse_hemisp_std
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)
• inst_down_long_shaded_case_temp
• Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• short_direct_normal_std
• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Maxima(down_short_diffuse_hemisp_max)
• Downwelling Shortwave Diffuse Hemisp. Irrad., Ventilated Pyranometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)