SGP/BRS/C1 - low downwelling shortwave readings

Downwelling shortwave (DS) values frequently drop below -10 W/m^2 at night, and are 
consistently 20-40 W/m^2 less than the calculated downwelling shortwave during the day in 
clear-sky conditions. Corrective maintenance on 12/1/2004 corrected this offset.  It is not 
clear which CM action corrected the problem since the DS instrument cable was grounded to a 
new location and the DS ventilator fan was found in poor condition and was replaced.  
Either of these issues could have led to the problem observed in this instrument.

• down_short_hemisp_std
• 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)

• inst_global

• Raw data stream - documentation not supported

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

SGP/BRS/C1 - Missing data due to Ice storm and clock problems

Data are missing due to power failures caused by an ice storm
and resulting system/instrument clock problems.

• site
• base_time
• Measured Downwelling Diffuse Shortwave Irradiance (dif)(difswfluxdn_measured)
• solar_cos_z
• Measured Downwelling Direct Shortwave Irradiance (dir)(dirfluxdn_measured)
• sswfluxdn_cloudeffect
• nsamples_clearsky_detection
• time_offset
• time_offset_LST
• difratiodn_measured_stdev
• gswfluxdn_cloudeffect
• difcloudeffect_normalized
• sswfluxdn_clearskyfit
• Measured Downwelling Global Shortwave Irradiance (gsw)(gswfluxdn_measured)
• Measured Surface Albedo from Shortwave Irradiance Measurements (alb)(albedosw_measured)
• guvbdn_measured
• lon
• Clear-sky Fit Estimated Downwelling Direct Shortwave Irradiance (cdir)(dirfluxdn_clearskyfit)
• difratiodn_clearskyfit
• Clear-sky Fit Estimated Sfc. Albedo from Shortwave Irrad. Measurements (calb)(albedosw_clearskyfit)
• lat
• nsamples_cloudfraction
• sswfluxdn_measured
• difratiodn_measured
• Clear-sky Fit Estimated Downwelling Global Shortwave Irradiance (csw)(gswfluxdn_clearskyfit)
• guvbdn_clearskyfit
• sun_earth_distance
• difswfluxdn_cloudeffect
• nsamples_gswfluxdn_clearskyfit
• base_time_LST
• alt
• nsamples_sswfluxdn_measured
• Fractional Sky Cover(cloudfraction)
• Clear-sky Fit Estimated Downwelling Diffuse Field Shortwave Irradiance (cdif)(difswfluxdn_clearskyfit)

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

• difswfluxdn_cloudeffect
• lat
• coef_clearsky_guvb_b
• coef_clearsky_guvb_a
• Clear-sky Fit Estimated Downwelling Direct Shortwave Irradiance (cdir)(dirfluxdn_clearskyfit)
• solar_cos_z
• guvbdn_measured
• sswfluxdn_measured
• coef_clearsky_albedo_a
• coef_clearsky_albedo_b
• Clear-sky Fit Estimated Sfc. Albedo from Shortwave Irrad. Measurements (calb)(albedosw_clearskyfit)
• sswfluxdn_cloudeffect
• coef_clearsky_ssw_a
• coef_clearsky_ssw_b
• coef_clearsky_difratio_b
• coef_clearsky_difratio_a
• sun_earth_distance
• coef_clearsky_gsw_b
• coef_clearsky_gsw_a
• coef_clearsky_dsw_c
• coef_clearsky_dsw_a
• sun_earth_distance_dailyaverage
• coef_clearsky_dsw_b
• lon
• base_time
• flag_clearsky_detection
• time_offset
• Measured Downwelling Direct Shortwave Irradiance (dir)(dirfluxdn_measured)
• difratiodn_clearskyfit
• guvbdn_clearskyfit
• coef_date
• Measured Downwelling Diffuse Shortwave Irradiance (dif)(difswfluxdn_measured)
• sswfluxdn_clearskyfit
• Clear-sky Fit Estimated Downwelling Diffuse Field Shortwave Irradiance (cdif)(difswfluxdn_clearskyfit)
• base_time_LST
• site
• difratiodn_measured
• Measured Downwelling Global Shortwave Irradiance (gsw)(gswfluxdn_measured)
• time_offset_LST
• alt
• Measured Surface Albedo from Shortwave Irradiance Measurements (alb)(albedosw_measured)
• Clear-sky Fit Estimated Downwelling Global Shortwave Irradiance (csw)(gswfluxdn_clearskyfit)
• gswfluxdn_cloudeffect

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

• Raw data stream - documentation not supported

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

SGP/BRS/C1 - NIP sensor failure

Normal incidence values of downwelling shortwave radiation were
               reported as -9999 (missing).  The NIP instrument was damaged by
               lightning in the area near the time of failure.

• 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
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

• inst_direct_normal

• Raw data stream - documentation not supported

SGP/BRS/C1 - Monthly Summary

Data quality this site-month is poor. This is due largely to the missing Upwelling
Shortwave and Upwelling Longwave the entire month. This problem has been ongoing for
several months now. DQPR # 124 asserted that the Global PSP was recording inaccurate
readings. Thus, the Global PSP was changed out on the 17th by site ops. Prior to the
17th, the Global PSP was falling below nighttime empirical limits on most nights and
there were severe 3 component failures during the day. The change out of the PSP
mitigated the severity of the 3 component failures and eliminated the nighttime empirical
limits failures. There were still substantial 3 component flags after the 17th.

• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• Radiation, shortwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_short_hemisp)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• 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)

SGP/BRS/C1 - Reprocess: Incorrect Calibration Coefficients

Lightening strike on or near 6/2/2004 took the BRS NIP(31747E6) out of service, on or near 
6/15 the NIP was replaced and the datalogger program was changed to reflect the new 
NIP(31343E6). On 8/5/2004 the DIR (Downwelling longwave) instrument was changed out and a new 
program was loaded to reflect a new DIR.  The new program contained the original 
installed shortwave instrument calibration coefficients including NIP 31747E6. Thus from 8/5 to 
when the shortwave instruments were changed out on 12/3 the wrong s/n and calibration 
factor (i.e. 31747E6) was applied to the actual NIP(31343E6)installed at BRS C1.

• 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
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

• inst_direct_normal

• Raw data stream - documentation not supported

SGP/BRS/C1 - Monthly Summary

Data quality this site-month is good. The offset in the Global PSP has been much improved, 
with an average nighttime offset of -4 W/m^2, since measures were taken on 17 DEC 2004 
to fix it. The Global PSP does not go below nighttime empirical limits all month. Global 
does fall below daytime empirical limits for significant time periods on the 2, 4, 5, 12, 
28, 30. There were still substantial 3 component flags 17 DEC 2004. The charcteristic 
three component failures are present through out the month, especially closer to the end of 
the month. The problem is about equally as bad in the morning as the evening.

The flags are usually high level yellow at their worst for any given day. Finally, there 
are the typical three component flags on the 29th as well, but these occur under cloudy 
skies. The data return to normal the next day and a cause for the problem cannot be 
determined.

• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• 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)

SGP/BRS/C1 - low downwelling shortwave readings

Downwelling shortwave (DS) values frequently drop below -10 W/m^2 at night, and are 
consistently 20-40 W/m^2 less than the calculated downwelling shortwave during the day in 
clear-sky conditions. Corrective maintenance on 12/17/2004 corrected this offset.  It is not 
clear which CM action corrected the problem since the DS instrument cable was grounded to 
a new location and the DS ventilator fan was found in poor condition and was replaced.  
Either of these issues could have led to the problem observed in this instrument.

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

• inst_global

• Raw data stream - documentation not supported

SGP/BRS/C1 - Reprocessed: Longwave Calibration error

Modified pyrgeometer calibration procedures were implemented beginning in June 2004. 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 instantaneous data records. 
Still, these data are considered far superior to the originally processed data. The 
reprocessed data were archived in November 2006.

• Downwelling Longwave Hemispheric Irradiance, Shaded Ventilated Pyrgeometer(down_long_hemisp_shaded)
• Radiation, longwave, at 10-m height, upwelling hemispheric irrad., 1-min avg(up_long_hemisp)
• Upwelling Longwave Hemispheric Net Infrared(up_long_netir)
• Downwelling Longwave Hemispheric Net Infrared(down_long_netir)

SGP/BRS/C1 - Reprocess: Calibration error in Downwelling Longwave measurement

On 20031211 the Downwelling LW pyrgeometer was replaced but the calibrations were not 
updated.  Calibrations have been corrected in data beginning 20040615.

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

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

SGP/BRS/C1 - SW Direct Normal incorrect

Apparent lightning strike in the instrument cluster area resulted in a failed NIP. Data 
are missing or incorrect.  

The SIRS was due for calibration change outs so the US, DS, DD and NIP were replaced. The 
updated program was loaded at approximately 06/14/2011 1739 GMT.

An estimate of direct normal values can be derived using the following formula:

short_direct_normal = (down_short_hemisp - down_short_diffuse_hemisp)/cos(zenith angle)

• 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
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

• inst_direct_normal

SGP/BRS/C1 - Tracker failure

Apparent lightning strike in the instrument cluster area resulted in a failed tracker. 
Site ops found the suntracker at home position, power cycled the suntracker and replaced 
fuse.

• down_short_diffuse_hemisp_std
• 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)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)

• inst_diffuse

SGP/BRS/C1 - Incorrect calibration coefficient for down_short_diffuse_hemisp

Applied calibration coefficient and serial number for down_short_diffuse was incorrect for 
the specified period.

• Radiation, shortwave, direct normal irradiance, 1-min avg(short_direct_normal)
• down_short_diffuse_hemisp_std
• 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)
• Radiation, shortwave, downwelling diffuse hemispheric irradiance, 1-min avg(down_short_diffuse_hemisp)

• inst_diffuse