SGP/BRS/C1 - Downwelling SW below empirical limit

Downwelling shortwave values appear to drop below the empirical limit (-10 W/m^2) at 
night, and during the day the values are less than the calculated downwelling shortwave by 
about 20-30 W/m^2 (at times close to 50 W/m^2 difference). Field techs performed maintenance 
but could not find obvious instrument problems.

The data exhibit the three component failure with global being flagged too low. The 
difference is likely due to the artifact of the cosine response of the particular installed PSP 
coupled with typical uncertainties of this set of installed radiometers. Also the unique 
variation of pyranometer responsivity (calibration factor) as a function of solar zenith 
angle could play a factor in the discrepancy.

• Irradiance, shortwave, downwelling, hemispheric, pyranometer, mifkba(down_short_hemisp_min)
• down_short_hemisp_std
• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Maxima(down_short_hemisp_max)
• Downwelling shortwave hemispheric irradiance, pyranometer(down_short_hemisp)

SGP/BRS/C1 - Loose cable connections

During the specified period the short_direct_normal (NIP instrument) measurement signal 
occasionally dropped out.  Site ops found a bad connection on the instrument and corrected 
it. 

Any missing short_direct_normal (NIP instrument) data are not recoverable but can be 
derived from existing down_short_hemsip and down_short_diffuse measurements.  However, this 
results in generally lower quality (i.e. higher uncertainty) data.  Users are advised to 
use measurements from the co-located SGP/SIRS/C1 datastream.

• Shortwave Direct Normal Irradiance(short_direct_normal)
• Irradiance, shortwave, direct normal, pyrheliometer, mifkba(short_direct_normal_min)
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

SGP/BRS/C1 - Reprocessing Notice (RID 1119)

See below for details of reprocessing that was completed on 20150228.  Original 
DQR category: 4 (Red, Incorrect).

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The CR23X datalogger was replaced with a CR3000 on 2/21/2012. Incorrect serial numbers and 
calibration coefficients were in the CR3000 program for down_short_hemisp PSP, 
down_short_diffuse_hemisp 8-48, short_direct_normal NIP, and down_long_hemisp PIR.

The correct S/N and coefficients during the affected time period:
down_short_hemisp: PSP- 30812F3; 127.06
down_short_diffuse_hemisp: 8-48- 33238; 109.51
short_direct_normal: NIP- 29851E6; 119.59 
down_long_hemisp: PIR- 30357F3; K0 0.00, K1 0.2577, K2 1.00, K3 -4.00, Kr 0.00

The incorrect S/N and coefficients during the affected time period:
down_short_hemisp: PSP- 9996F3; 100.00
down_short_diffuse_hemisp: 8-48- 99993; 100.12
short_direct_normal: NIP- 99995; 100.00
down_long_hemisp: PIR- 99992; K0 0, K1 0.25, K2 1, K3 -4, Kr 0

• down_short_hemisp_std
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer, maxima(down_short_diffuse_hemisp_max)
• down_short_diffuse_hemisp_std
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer, minima(down_short_diffuse_hemisp_min)
• inst_down_long_shaded_case_temp
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer(down_long_hemisp_shaded)
• Shortwave Direct Normal Irradiance(short_direct_normal)
• down_long_hemisp_shaded_std
• Irradiance, shortwave, downwelling, hemispheric, pyranometer, mifkba(down_short_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• Irradiance, shortwave, direct normal, pyrheliometer, mifkba(short_direct_normal_min)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• short_direct_normal_std
• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Maxima(down_short_hemisp_max)
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Downwelling longwave hemispheric net infrared(down_long_netir)
• inst_down_long_shaded_dome_temp
• Downwelling shortwave hemispheric irradiance, pyranometer(down_short_hemisp)

SGP/BRS/C1 - Instrument

NIP data suspect during affected time period, resulting in low values for derived short 
direct normal difference

• Shortwave Direct Normal Irradiance(short_direct_normal)
• Irradiance, shortwave, direct normal, pyrheliometer, mifkba(short_direct_normal_min)
• short_direct_normal_std
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)

SGP Site Power Outage Due to Winter Storm

On Saturday and Sunday, December 26 and 27th a powerful winter storm (Goliath) brought 
sleet and freezing rain to much of Oklahoma with wind gusts of 45 MPH at times. The result 
was very very slick roads and mass power outages.
 
The SGP central facility lost power at 8:55 PM CDT on Sunday, December 27th.  
The power was restored on 7:56 PM CDT on Wednesday, December 30th
 
Site Emergency procedures were activated and Technicians drained water out of instrument 
reservoirs and other measures as needed, early Monday morning.
 
On Wednesdays as roads and power started was restored to much of the areas east of I-35 , 
Site Technicians performed maintenance on several Extended Facilities.

During this period, data are potentially missing, incorrect, or suspect.  Carefully 
inspect the data before use.

• North latitude(lat)
• vBatt
• down_short_diffuse_hemisp_std
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer, minima(down_short_diffuse_hemisp_min)
• inst_down_long_shaded_case_temp
• Irradiance, longwave, downwelling, hemispheric, shaded pyrgeometer(down_long_hemisp_shaded)
• Shortwave Direct Normal Irradiance(short_direct_normal)
• East longitude(lon)
• down_long_hemisp_shaded_std
• inst_up_long_case_temp
• Irradiance, shortwave, downwelling, hemispheric, pyranometer, mifkba(down_short_hemisp_min)
• Downwelling Longwave Hemispheric Irrad., Shaded Ventilated Pyrgeometer, Minima(down_long_hemisp_shaded_min)
• Upwelling longwave hemispheric irradiance, pyrgeometer(up_long_hemisp)
• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Maxima(down_short_hemisp_max)
• short_direct_normal_std
• base_time
• Downwelling shortwave hemispheric irradiance, pyranometer(down_short_hemisp)
• Downwelling longwave hemispheric net infrared(down_long_netir)
• down_short_hemisp_std
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer, maxima(down_short_diffuse_hemisp_max)
• Upwelling Longwave Hemispheric Irradiance, Pyrgeometer, Maxima(up_long_hemisp_max)
• Upwelling Longwave Hemispheric Irradiance, Unventilated Pyrgeometer, Minima(up_long_hemisp_min)
• Upwelling shortwave hemispheric irradiance, pyranometer(up_short_hemisp)
• Altitude above mean sea level(alt)
• up_long_hemisp_std
• Upwelling Shortwave Hemispheric Irradiance, Unventilated Pyranometer, Minima(up_short_hemisp_min)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
• Irradiance, shortwave, direct normal, pyrheliometer, mifkba(short_direct_normal_min)
• inst_up_long_dome_temp
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Upwelling longwave hemispheric net infrared(up_long_netir)
• Upwelling Shortwave Hemispheric Irradiance, Pyranometer, Maxima(up_short_hemisp_max)
• up_short_hemisp_std
• time_offset
• inst_down_long_shaded_dome_temp