Data Quality Reports for Session: 101483 User: perez Completed: 09/07/2006


TABLE OF CONTENTS

DQR IDSubjectData Streams Affected
D040405.2SGP/SIRS/E7 - PSP dome contaminationsgpsirsE7.b1, sgpsirs20sE7.a0
D040621.3SGP/SIRS/E7 - Reprocess: Incorrect calibration coefficients applied to downwelling
longwave
sgpsirsE7.00, sgpsirsE7.b1
D040831.2SGP/SIRS/E7 - Reprocess: Incorrect shortwave radiometer calibration coefficientssgpsirsE7.00, sgpsirsE7.b1
D050218.1SGP/SIRS/E7 - Reprocess: Incorrect DIR calibration coefficientssgpsirsE7.00, sgpsirsE7.b1, sgpsirs20sE7.a0
D050307.3SGP/SIRS/E7 - Downwelling Shortwave incorrectsgpsirsE7.00, sgpsirsE7.b1
D060630.15SGP/SIRS/E7 - Reprocess: Longwave Calibration errorsgpsirsE7.b1


DQRID : D040405.2
Start DateStart TimeEnd DateEnd Time
03/30/2004143004/06/20042100
Subject:
SGP/SIRS/E7 - PSP dome contamination
DataStreams:sgpsirsE7.b1, sgpsirs20sE7.a0
Description:
Values of hemispheric downwelling shortwave radiation differed from derived values by 45 
W/m^2 on 03/30 around 1430 GMT under clear sky conditions due to dirt on the dome.

Maintenance reported cleaning heavy dust from dome on 04/06 2030 GMT.
Measurements:sgpsirs20sE7.a0:
  • Instantaneous Downwelling Hemispheric Shortwave, Unshaded Pyranometer Thermopile
    Voltage(inst_global)

sgpsirsE7.b1:
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Maxima(down_short_hemisp_max)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer(down_short_hemisp)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Standard
    Deviation(down_short_hemisp_std)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Minima(down_short_hemisp_min)


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DQRID : D040621.3
Start DateStart TimeEnd DateEnd Time
04/20/2004182506/29/20041915
Subject:
SGP/SIRS/E7  - Reprocess: Incorrect calibration coefficients applied to downwelling 
longwave
DataStreams:sgpsirsE7.00, sgpsirsE7.b1
Description:
While attempting to correct calibration coefficients (see D040831.2) a new
datalogger program was loaded which applied the wrong serial number and
calibration coefficients to the downwelling longwave measurement.

Recalculate data from the b1 datastream using the thermopile output, case and
dome temperatures following this procedure:

1) Obtain the following variables from the b1 datafile for each minute:
      Td = inst_down_long_shaded_dome_temp[degK]
      Tc = inst_down_long_shaded_case_temp[degK]
      Wnet = down_long_netir[W/m2]

2) For each one minute data entry in b1 backout the thermopile voltage
     V[uV] = Wnet/K1(wrongly applied DIR cal coeffs) = 
down_long_netir[W/m2]/0.24764[W/m2/uV]

3) Apply for each one minute data entry:
     Winc [W/m^2] = K0+K1*V+ K2*Sigma*Tr^4 + K3*Sigma*(Td^4 - Tr^4)
   where,
     Winc= incoming radiation [W/m2]
     V   = PIR thermopile voltage [uV]
     K0 =  offset W/m2 = -14.61
     K1 =  1/Responsivity of TP [W/m2*uV] = .24832
     K2 =  case emittance w/ thermistor correction [unitless] = 1.028
     K3 =  thermal conductance between dome and receiver & therm. correction [unitless] = 
-2.249
     Sigma= 5.67 x 10^-8 [W/(sq mK^4)] = Stephan-Boltzman Constant
     Td  = PIR dome thermistor temperature [deg K]
     Tr = Tc + 0.0007044 * V
          where 7.044e-4 is empirically derived for an Eppley PIR
     Tc  = PIR case receiver temperature [deg K]

Other datastream corrections that use the DIR measurements will require
similar corrections.

See the following web site for additional information on the pyrgeometer
equations, specifically sections 2.1(Single Calibration Factor Approach)
and 2.2 (Four Coefficient Calibration Approach)
     http://www.arm.gov/docs/instruments/static/pyrg.html
Measurements:sgpsirsE7.b1:
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Standard
    Deviation(down_long_hemisp_shaded_std)
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Minima(down_long_hemisp_shaded_min)
  • Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer(down_long_hemisp_shaded)
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Maxima(down_long_hemisp_shaded_max)

sgpsirsE7.00:
  • Raw data stream - documentation not supported(Raw data stream - documentation not supported)


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DQRID : D040831.2
Start DateStart TimeEnd DateEnd Time
02/20/2004184504/20/20041825
Subject:
SGP/SIRS/E7  - Reprocess: Incorrect shortwave radiometer calibration coefficients
DataStreams:sgpsirsE7.00, sgpsirsE7.b1
Description:
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)*108.50
US(corrected) = (US/113.19)*110.10
NIP(corrected)= (NIP/120.17)*122.26
DS(corrected) = (DS/118.46)*122.56
Measurements:sgpsirsE7.b1:
  • Shortwave Direct Normal Irradiance, Pyrheliometer(short_direct_normal)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Maxima(down_short_hemisp_max)
  • Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer(down_short_hemisp)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Standard
    Deviation(down_short_hemisp_std)
  • Upwelling (10 meter) Shortwave Hemispheric Irradiance, Ventilated Pyranometer,
    Standard Deviation(up_short_hemisp_std)
  • Upwelling (10 meter) Shortwave Hemispheric Irradiance, Ventilated Pyranometer(up_short_hemisp)
  • Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
    Minima(down_short_diffuse_hemisp_min)
  • Upwelling (10 meter) Shortwave Hemispheric Irradiance, Ventilated Pyranometer,
    Maxima(up_short_hemisp_max)
  • Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
    Standard Deviation(down_short_diffuse_hemisp_std)
  • Upwelling (10 meter) Shortwave Hemispheric Irradiance, Ventilated Pyranometer,
    Minima(up_short_hemisp_min)
  • Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer,
    Maxima(down_short_diffuse_hemisp_max)
  • Shortwave Direct Normal Irradiance, Pyrheliometer, Minima(short_direct_normal_min)
  • Shortwave Direct Normal Irradiance, Pyrheliometer, Standard Deviation(short_direct_normal_std)
  • Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Minima(down_short_hemisp_min)

sgpsirsE7.00:
  • Raw data stream - documentation not supported(Raw data stream - documentation not supported)


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DQRID : D050218.1
Start DateStart TimeEnd DateEnd Time
11/02/2004204502/22/20052050
Subject:
SGP/SIRS/E7 - Reprocess: Incorrect DIR calibration coefficients
DataStreams:sgpsirsE7.00, sgpsirsE7.b1, sgpsirs20sE7.a0
Description:
Incorrect DIR calibration coeffs and serial numbers were applied to the data from 
11/02/2004 when the shortwave instruments were changed out.  Field techs corrected the program 
during longwave instrument replacement on 2/22/2005.

Users may wish to attempt to reprocess the data by applying the following method.  Note, 
this may result in additional errors due to the averaging of the 20s data.

Use 20s data (available averaged in 60s b1 file) to reconstruct downwelling IR (DIR) data 
from the PIR instrument.  Use case and dome temperatures as supplied in variables:
inst_down_long_dome_temp[K]
inst_down_long_case_temp[K]
Back out thermopile(tp) output in mV from the tp in W/m2 as described:
tp[mV] = (down_long_netir[W/m2]/WrongK1[W/(m2*uV)])/1000
where WrongK1 is the K1 term applied to the DIR during the DQR period.  Use the following 
coefficients to recreate the dataset following the described method in the SIRS handbook 
Sec 7.1.2 available at http://www.arm.gov/instruments/instrument.php?id=33 
The coefficients to be used are as follows:
WrongK1 = .2476
K0 = -14.61
K1 = .24832
K2 = 1.028
K3 = -2.249
Kr = 7.044E-4
Measurements:sgpsirs20sE7.a0:
  • Instantaneous Downwelling Pyrgeometer Dome Thermistor Resistance, Shaded
    Pyrgeometer(inst_down_long_shaded_dome_resist)
  • Instantaneous Downwelling Pyrgeometer Case Thermistor Resistance, Shaded
    Pyrgeometer(inst_down_long_shaded_case_resist)
  • Instantaneous Downwelling Pyrgeometer Thermopile Voltage, Shaded Pyrgeometer(inst_down_long_hemisp_shaded_tp)

sgpsirsE7.b1:
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Standard
    Deviation(down_long_hemisp_shaded_std)
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Minima(down_long_hemisp_shaded_min)
  • Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
  • Instantaneous Downwelling Pyrgeometer Dome Thermistor Temperature, Shaded
    Pyrgeometer(inst_down_long_shaded_dome_temp)
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer(down_long_hemisp_shaded)
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer, Maxima(down_long_hemisp_shaded_max)
  • Instantaneous Downwelling Pyrgeometer Case Thermistor Temperature, Shaded
    Pyrgeometer(inst_down_long_shaded_case_temp)

sgpsirsE7.00:
  • Raw data stream - documentation not supported(Raw data stream - documentation not supported)


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DQRID : D050307.3
Start DateStart TimeEnd DateEnd Time
03/03/2005220004/05/20051950
Subject:
SGP/SIRS/E7 - Downwelling Shortwave incorrect
DataStreams:sgpsirsE7.00, sgpsirsE7.b1
Description:
Downwelling shortwave values dropped off to unrealistic values frequently 
at this site (usually between 1600 GMT and 0000 GMT).  SGP techs found this was due to a 
bad multiplexer and it was replaced 04/05/2005 1950GMT along with the downwelling 
shortwave cable.
Measurements:sgpsirsE7.b1:
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Maxima(down_short_hemisp_max)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer(down_short_hemisp)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Standard
    Deviation(down_short_hemisp_std)
  • Downwelling Shortwave Hemispheric Irradiance, Ventilated Pyrgeometer, Minima(down_short_hemisp_min)

sgpsirsE7.00:
  • Raw data stream - documentation not supported(Raw data stream - documentation not supported)


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DQRID : D060630.15
Start DateStart TimeEnd DateEnd Time
02/20/2004200002/07/20062005
Subject:
SGP/SIRS/E7 - Reprocess: Longwave Calibration error
DataStreams:sgpsirsE7.b1
Description:
Modified pyrgeometer calibration procedures were implemented beginning in December 2003.  
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 are 
being reprocessing to remove the calibration bias.  Note, this also affected standard 
deviation, maximum and minimum data fields.
Measurements:sgpsirsE7.b1:
  • Downwelling Longwave Hemispheric Net Infrared(down_long_netir)
  • Upwelling (10 meter) Longwave Hemispheric Irradiance, Ventilated Pyrgeometer(up_long_hemisp)
  • Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer(down_long_hemisp_shaded)
  • Upwelling Longwave Hemispheric Net Infrared(up_long_netir)


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