DQR ID | Subject | Data Streams Affected |
---|---|---|
D040405.2 | SGP/SIRS/E7 - PSP dome contamination | sgpsirsE7.b1, sgpsirs20sE7.a0 |
D040621.3 | SGP/SIRS/E7 - Reprocess: Incorrect calibration coefficients applied to downwelling longwave | sgpsirsE7.00, sgpsirsE7.b1 |
D040831.2 | SGP/SIRS/E7 - Reprocess: Incorrect shortwave radiometer calibration coefficients | sgpsirsE7.00, sgpsirsE7.b1 |
D050218.1 | SGP/SIRS/E7 - Reprocess: Incorrect DIR calibration coefficients | sgpsirsE7.00, sgpsirsE7.b1, sgpsirs20sE7.a0 |
D050307.3 | SGP/SIRS/E7 - Downwelling Shortwave incorrect | sgpsirsE7.00, sgpsirsE7.b1 |
D060630.15 | SGP/SIRS/E7 - Reprocess: Longwave Calibration error | sgpsirsE7.b1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/30/2004 | 1430 | 04/06/2004 | 2100 |
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:
sgpsirsE7.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/20/2004 | 1825 | 06/29/2004 | 1915 |
Subject: | SGP/SIRS/E7 - Reprocess: Incorrect calibration coefficients applied to downwelling |
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:
sgpsirsE7.00:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/20/2004 | 1845 | 04/20/2004 | 1825 |
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:
sgpsirsE7.00:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
11/02/2004 | 2045 | 02/22/2005 | 2050 |
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:
sgpsirsE7.b1:
sgpsirsE7.00:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/03/2005 | 2200 | 04/05/2005 | 1950 |
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:
sgpsirsE7.00:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/20/2004 | 2000 | 02/07/2006 | 2005 |
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:
|