SGP/SIRS/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.

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SGP/SIRS/E2 - 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.

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SGP/SIRS/E2 - Ventilator Fan Failure

Measured downwelling shortwave data was very questionable, reporting 
nighttime values as low as -50 W/m^2, while differing from calculated 
downwelling shortwave by as much as 50 W/m^2 lower during the day. The 
first indication of a problem was around 10 UTC, 9/14, when measured 
DS values suddenly dropped below 10 W/m^2 for about a 2 hour period 
before sunrise, then were consistently lower than calculated DS by as 
much as 40 W/m^2 during the day.

The problem got progressively worse with time until the ventilator fan was
replace on 9/25.  Ventilator fan failure changed the fundamental
operating characteristics of this PSP and resulted in unpredictable biased
measurements which cannot be corrected without additional empirical
characterization of the radiometer in question.

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SGP/SIRS/E1 - failed SIRS multiplexer

Beginning 10/14, a failed multiplexer resulted in missing 
                  downwelling shortwave data and downwelling and upwelling 
                  longwave data which were much too low. The multiplexer 
                  handles data for the longwave instruments (UIR and DIR) 
                  case and dome temperatures as well as the downwelling shortwave 
                  hemispheric instrument (DS).

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SGP/SIRS/E1 - Unknown - Downwelling shaded longwave measurement incorrect

Downwelling longwave values were very noisy and out of range 
               due to a missing PIR case temperature measurement. Faulty 
               wiring to the case temperature thermistor on the downwelling 
               longwave IR instrument (PIR) was the likely cause of
               the problem.
               On 11/18, the E1 tracker and associated instruments (direct 
               shortwave -NIP, hemispheric shaded shortwave -8-48 and 
               hemispheric shaded longwave - problem PIR) were moved to a new 
               tracker stand.  Rewiring the instrument corrected the problem.

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SGP/SIRS/E1/E2/E3/E5/E8 - Snow on Radiometers

A large discrepancy between the measured values of downwelling hemispheric shortwave 
radiation and the derived values occurred on 2/02 at the listed sites.  The difference is on 
the order of 200 Wm^(-2) at E2 and to a lesser extent at the other affected stations.  
This problem most likely resulted from a previous day or night snow/ice accumulation on 
the Direct(NIP), Downwelling Sortwave(PSP) and/or  Downwelling Diffuse(8-48) instruments.  
During the morning hours of 02/02, Approx 1300-2000GMT, snow/ice was covering one or more 
of these three instruments resulting in faulty readings and incorrect derived 
downwelling shortwave values as well.  Instrument readings indicate the problem resolved itself 
later in the day through normal meltoff.

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SGP/SIRS/E2 - Reprocessing Notice (RID 293)

See below for details of reprocessing that was completed on 20150929.  Original 
DQR category: 4 (Red, Incorrect).

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During the pyrgeometer instrument (PIR) changout a datalogger program was loaded with 
incorrect calibration coefficients for the shortwave instruments.  The affected measurements 
were : downwelling diffuse (DD), upwelling shortwave(US), direct normal (NIP) and 
downwelling shortwave(DS)

Recalculate irradiances by determining original mV signal and reapplying the correct 
calibration coefficients.  For each one minute irradiance value perform the following 
calculations by instrument:
DD(corrected) = (DD/107.24)*118.11
US(corrected) = (US/113.19)*118.21
NIP(corrected)= (NIP/120.17)*119.08
DS(corrected) = (DS/118.46)*117.33

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SGP/SIRS/E1 - Reprocessing Notice (RID 292)

See below for details of reprocessing that was completed on 20151002.  Original 
DQR category: 4 (Red, Incorrect).

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During the pyrgeometer instrument (PIR) changout a datalogger program was loaded with 
incorrect calibration coefficients for the shortwave instruments.  The affected measurements 
(instruments) were : downwelling diffuse (8-48), upwelling shortwave(PSP), direct normal 
(NIP) and downwelling shortwave (PSP)

Recalculate irradiances by determining original mV signal and reapplying the correct 
calibration coefficients.  For each one minute irradiance value perform the following 
calculations by instrument:
DD(corrected) = (DD/107.24)*109.01
US(corrected) = (US/113.19)*111.47
NIP(corrected)= (NIP/120.17)*114.82
DS(corrected) = (DS/118.46)*116.51

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SGP/SIRS/C1/E13 - Incorrect calibration coefficients

After the DIR changeout on 8/27, the DLH measurements at the central facility vary 
significantly between pyrgeometers by as much as 65 Wm^(-2).  It was discovered that the two 
downwelling pyrgeometers destined for C1 and E13 may have been swapped during installation.  
The instrument mentor is unsure of applied calibration coefficients during this DQR's 
time period.  Backing out new downwelling longwave irradiances would be difficult in this 
case. Fortunately, the problem period is less than a fortnight.

• Raw data stream - documentation not supported

SGP/SIRS/E1 - broken cable on DSDH (aka DD) measurment instrument - Eppley 8-48.

Occasionally, the downwelling shortwave diffuse hemispheric (DSDH) readings spike to 
unreasonably low levels, causing derived downwelling shortwave hemispheric (DSH) readings to 
spike well below the actual DSH readings.  Technicians repaired the DSDH instument (an 
Eppley 8-48) cable on 02/08/2005 2055GMT.  There have been no dropouts since that time.

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SGP/SIRS/E2 - Tracker mis-alignment

The solar tracker was not working correctly at this site from 2/3/2005 to 2/5/2005 
2359GMT.  After this time tracker mounted instruments appear to have been responding correctly.  
There was no maintenance intervention that rectified the tracking problem. This has 
happened in the past with the SGP SciTec trackers.

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SGP/SIRS/E2 - Reprocessed: Incorrect DIR calibration coefficients

During the DIR/UIR instrument changeout on 2/10/2005 the new datalogger program contained 
incorrect calibration coefficients for the DIR instrument. The program was corrected on 
3/10/2005.

These data were reprocessed and archived in September 2006.

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SGP/SIRS/C1 - Reprocess: Adjust Direct Normal Irradiance

Direct normal broadband shortwave irradiance measured by NIP s/n 30722E6 was found to have 
a 0.62%% negative bias when compared in-situ with absolute cavity radiometer 
measurements taken on August 21, 2000.  The estimated measurement uncertainty of the calibration of 
NIP s/n 30722E6 on July 18, 2000 was -2.6% to +4.8%.  

Data from NIP s/n 30722E6 can be adjusted according to the in-situ comparisons to reduce 
the apparent measurement bias.

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SGP/SIRS/C1  - sun tracker power failure

C1 experienced a sun tracker power faulure.  The tracker was reset by onsite personnel 
shortly after the power failed.  Only shaded and direct instruments were affected - i.e. the 
downwelling diffuse measurement from the 8-48 B&W pyranometer and the direct normal 
measurement from the NIP pyrheliometer.  The downwelling longwave PIR data was unaffected by 
this event.

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SGP/SIRS/E1 - Reprocess: incorrect calibration coefficients for US (upwelling shortwave) 
instrument

During the changeover from 4 to 1 coefficient for the PIRs at SIRS/E1 (PIF) the datalogger 
program was programmed with the wrong calibration coefficient and serial number for the 
US PSP instrument measuring the Upwelling Hemispheric Shortwave radiation. The 
calibration coefficient was 114.43 W/m2/mV (instrument 30618F3) when it should have been 
104.47W/m2/mV (instrument 29618F3)

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SGP/SIRS/E1 - Intermittantly missing downwelling diffuse

Starting on or about 10/26/2005 the downwelling diffuse hemispheric irradiance (Eppley 
8-48) instrument had intermittant missing values. Technicians found a loose wire on the 
instrument connector and repaired it on 4/4/2006. 

Use global shortwave hemispheric (PSP) component - normal incident component (CosZA*NIP) 
to calulate diffuse component.  Comparison of absolute difference between actual and 
computed diffuse component values and diffuse standard deviations > 1-2 W/m2 can help filter 
the noisy diffuse data.  There is no standard method.

• Raw data stream - documentation not supported

SGP/SIRS/C1 - Upwelling SW cable problem

Starting 11/13/2006, the C1 SIRS Upwelling Shortwave (up_short_hemisp) started to show 
large differences in comparison to co-located E13 SIRS and C1 IRT25m.  After much 
troubleshooting and gnashing of teeth it was discovered that rodents had chewed through the 
instrument cables at the bottom of the tilt tower. Cables were replaced 01/23/2007 1930GMT.

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SGP/SIRS/C1 - Reprocess: Incorrect calibration coefficients

Incorrection calibration coefficients were used in the C1/SIRS datalogger program. The 
PSP-US (upwelling shortwave global hemispheric), 30943F3 should be 126.93 not 129.93 
[W/m2/mV].

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SGP/SIRS/C1 - Upwelling LW cable problems

Troubleshooting of the upwelling shortwave instrument on Jan 3rd 2007 caused problems with 
the co-located upwelling longwave hemispheric irradiance Eppley PIR instrument (aka 
UIR).  Data dropouts persisted from this date to the final resolution of both shortwave and 
longwave instrument problems.  Rodents had chewed through the instrument cables.  The 
cables were replaced 01/23/2007 1930GMT.

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SGP/SIRS/C1/E1/E10/E11/E12/E13/E15/E16/E18/E19/E2/E20/E21/E22/E24/E25/E27/E3/E4/E5/E6/E7/E8/E9 - Ice

Ice storms affected the SGP central and extended facilities starting Dec 10 0000GMT to 
mid/late December. Each facility was affected at various times and degrees dependant on 
elevation, latitude and whether power failed for short or extended periods of time.  By 
December 15th most ice had melted from the radiometers at all the faclities but power outages 
and tracker failures persisted at some stations.

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SGP/SIRS/E1 - Obstruction

The down_short_hemisp measurement is adversly affected by the PSP instrument having an 
extremely dirty dome during this time period affecting daytime data starting on 6/28/2008 at 
23:00 GMT to PM on 7/8/2008 2150.

• Raw data stream - documentation not supported

SGP/SIRS/E1 - Tracker Failure

On 7/4/2008 the tracker at this site failed.  Affected measurements are 
down_short_diffuse_hemisp (8-48) and short_direct_normal (NIP). These will be inaccurate during this time.  
PM replaced the tracker on 7/8/2008 2150.  Note that the down_short_hemisp (PSP) 
instrument was also extremely dirty during this time (see D080702.1 and DQPR 1990).  This pretty 
much makes all data from this station unusable during this time.  longwave measurements 
will be relatively unaffected by these failures.

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SGP/SIRS/C1 - Sensor alignment/level

During the time range specified the downwelling shortwave DS radiometer (down_short_hemisp 
measurement) was slightly out of level.  The affects on data quality are within the 
uncertainly of the instrument.  However, the derived DS value (component sum of direct and 
diffuse shortwave) should be used during this time period.  Any of the associated VAPs 
(QCRAD, Central Facility Best Estimate) use the component sum by default and will not be 
adversely affected.

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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.

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SGP/SIRS/C1 - Data System Upgrade: Data Missing

The site data system was upgraded.  Data were not collected during this period.

• Raw data stream - documentation not supported